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DIY liquid auto doser

76K views 96 replies 32 participants last post by  TankAaron 
#1 ·
Ok... I'm lazy. Super lazy. I wanted to be able to fertilize daily without actually FERTILIZING daily, ya know? So some people here in the past talked about using peristaltic pumps with timers but I haven't seen anyone actually slap together a working system and post... so I'll do it! I'll first go through a run-down of my materials...

6 peristaltic pumps from www.aptinstruments.com. I used the OEM SP100 pumps (18rpm) w/ 1.6mm norprene tubing (about 0.9ml/min flow). i wanted to be able to dose up to 6 different wet ferts, so i bought six. wanna do 3? buy 3.

for the controllers, i got lazy... i picked up a bunch of table lamp digital timers off amazon.com. they were about 12 bucks a piece and have batteries in case of brief power outages. i put one timer on each pump so i could run them independently. if you are good and know what ratios you need to dose, you can get away with fewer. i went for maximum flexibility (at a much greater expense, though). the timers do an OK job. they have 2 "events" so you can even choose to dose twice a day if you'd like. in addition, you can easily turn them "on" for a few minutes manually if you want to dose something in particular.
http://www.amazon.com/Intermatic-TB...ref=sr_1_1?ie=UTF8&s=hi&qid=1234121541&sr=8-1

i also ordered about 50 feet of norprene tubing from APT as well. in addition, i picked up a few 90 degree elbow connectors so i could make the tube "hook" over the lip of the aquarium.

i have a prototype shop at work, so i whipped up a small "stand" to hold the reservoirs and the pumps are attached above. you can make this out of wood, metal, plastic, WHATEVER. it is not important at all. i used 1/2 gallon milk jugs (cleaned thoroughly) because they are tall and skinny so i could squeeze them in under my stand nicely.

as you can see, each side has 3 jugs and 3 pumps. the desktop lamp timers are nice because the "controller" portion has a cord that runs back to the power strip, so i could mount everything on the door.

so far, i've been running the pumps for about 1 month and i'm very happy. i keep slowly upping the time because i think there is a lot of backpressure so 0.9ml/min isn't what the flow seems to be. something less than that. but since everything is controlled independently, i can just increase whatever i need to increase. i can easily see what ferts are running low. i just used a label maker to clearly label everything. i spray-painted the "stand" black just so i didn't have to look at the bare metal (plus i'm avoiding rust).

oh, the only downside to the lamp timers is that they aren't grouned, so you should probably ground the pumps (mine were not grounded at the time i took these pictures).

it's not perfect, pretty, or sexy... but it works! you have no idea how nice it is just knowing that my ferts get dumped in every morning before the lights go on. and the 1/2 gallon jugs hold quite a lot of ferts... so i don't have to fill them very often. the ultimate in low maintenance!

and to avoid contamination, the output tubes are NOT in contact with the water. the output tubes bend over the lip of the aquarium to hook on, but there is a significant gap between the tubing and the water. the tubes are always filled with fertilizer, so people should keep that in mind if they ever set something like this up!

all in all... maybe around 500 bucks for the pumps and timers. everything else is cheap. and again... 6 independently controlled pumps should be overkill for anyone here. i would assume most people would only dose 2, 3, or 4 different liquids.

JP
 

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#2 ·
I always love DIY projects and I'm in the process of making a DIY Dosing pump. I like what you have done, but I don't like the price tag!! ;)

Anyway, have you ever taken a look at the "Tom Aquatics Aqua Lifter—Dosing Pump". You could get those for $15 and put them on a digital time for 1 minute. This would be a lot cheaper!!!

g
 
#3 ·
yeah i didn't like the price tag either, but it has worked out to be pretty good. plus these are fairly heavy duty pumps... i plan on running them for a looooooong time.

i haven't seen the tom's pump thing before (just looked at it). certainly interesting... i never found any decent stuff in my searches so i decided to suck it up and do this. it was a while ago... i was just too lazy to post the pictures up here!

i'd be interested in seeing the durability of these 15-dollar pumps, plus the actual strength (can these push liquid against gravity for 5-ish feet?)... but definitely good for the budget-minded (I know I would have jumped all over them when I was a poor college bum).

thanks for sharing!
 
#4 ·
Yeah, I think those cheap tom's dosing pumps are only rated for 30". I thought I read that somewhere. Head pressure is not as big of an issue for me cause I'm building an all in one inline Heater, CO2 Reactor, Liquid Ferts which will all be under the tank.

I'm actually working on a project that I use an air pump going into a gang value concept. The parts should be coming in this week.

g
 
#6 ·
it's not perfect, pretty, or sexy... but it works! you have no idea how nice it is just knowing that my ferts get dumped in every morning before the lights go on. and the 1/2 gallon jugs hold quite a lot of ferts... so i don't have to fill them very often. the ultimate in low maintenance!
You're a man after my my heart. How long has this been up and running? Any issues, like balancing ferts, or salt build-ups, or hoses cracking, or............?

I had made up my mind to purchase dosers for ferts a few months ago. I do worry about the long term issues. Thanks for the post, this is great!

Oh, the importance is compounded during football season, hunting season, and good enough weather to ride a motorcycle. Maintenance is a hard crew to keep around.;)
 
#7 ·
Why the air gap? I'm setting up a tank with everything coming through bulkheads in the bottom of the tank. Would check valves at the point of introduction to the water stream serve the same purpose?
Those dosing pumps are sort of positive displacement by the cam pinching the hose aren't they? I've got access to a pretty good toy shop at work too and love your set up. Bob
 
#8 ·
so far, it's been up and running for about 2-ish months. it's been solid so far. i just keep tweaking the fert amount. with the independent timers, it's quite easy, so i don't worry about balancing. need more K? run the K pump for 2 more minutes per day. done. And the 1/2 gallon jugs last quite a while (the lowest one is still 1/2 full). so, i'm quite happy with it so far.

obviously, 2 months isn't going to crack and destroy anything yet... the norprene tubing SHOULD last quite a long time, though. i hope. that's the plan at least. and if it doesn't... it will take me 10 minutes to replace all the tubing.

as for the air gap... i did it so the aquarium water (and the microorganisms in it) would not come in contact with a 6-foot tubes of pure fertilizers. i'm pretty sure gunk would start growing and living in the tubes and it would just be bad in general. so now, stuff just "falls" into the water and the tubes stay pure.

as for the idea of a check valve... it SOUNDS ok, but the cautious side of me says no, and here's why: the pumps are extremely slow. i mean, this thing DRIPS ferts into my tank. drip..... drip.... drip... these are IV pumps. so i'm sure the check valves would open and the ferts would go in, but i think there would be some bi-directional flow as soon as the valve opened, because the pressure is just SO low. so i THINK there would still be some sort of back flush. i'm not certain, but it's not something i wanted to test on my system. besides, draping it over the back of the tank really is no big deal. the tubing is very flexible and small. but if you want to give it a go with check-valves, please do and give us feedback!

as for the pumps... the company also sells pumps with controllers built in. so they have the same capabilities of what i "created." however, they were quite a bit more expensive than my 12-dollar table lamp timers. plus my lamp timers have small internal batteries so the settings aren't erased during a power outage (or if i just unplug stuff for fun). so that's a bonus.

anyway, i'm sure there are a few ways of doing this. i know a lot of people here spend so much time perfecting their ferts but then they still dose manually. i just wanted everyone to see that YOU DON'T HAVE TO DO THIS! STOP THE MADNESS!

this was definitely a worth-while project. i am much happier with my aquarium when it doesn't look like a giant maintenance CHORE. i think on my next tank (many years from now), i'm going to build in some sort of an "easy" water-change solution. then i'll reach nirvana.


JP
 
#11 ·
I was thinking of diluting the concentrations more, say 10-1 so I could pump more volume to make the metering easier and flush the lines better. I may still give it a try as I just tore down my 26gal bowfront to drill the bottom. If that dosn't work watch for my new 75 gal bowfront!:D
 
#12 ·
diluting would work, i guess... it didn't really seem like an option for me. i'm going for super lazy. therefore, i don't want to keep re-filling the reservoirs! heck, i hooked this thing up around xmas and i have only used about 2/3 of my potassium reservoir! so i figure at MOST, i'll have to fill this thing up 4 times per year. that sounds much better to me than filling it 40 times per year :-D

line flush is another interesting idea... i don't know how the lines will behave over time. i guess i'll just find out. SO FAR, no problems though. i really love not dosing daily. i really, really love it.... :)
 
#13 · (Edited)
Hey great job on the DIY. freemann also has some DIY dosing pumps.

By the way, I can't access the web page for some reason. I keep getting text instead of a page with info. How much were they per pump?

Also, Tom Aquatics Aqua Lifter—Dosing Pump aren't good for dosing. They have nearly no pressure when it comes to liquids. If you were to use them, they'd have to be on the same level as the rim of the tank to pump liquid.
 
#14 ·
Hey great job on the DIY. freemann also has some DIY dosing pumps.

By the way, I can't access the web page for some reason. I keep getting text instead of a page with info. How much were they per pump?

Also, Tom Aquatics Aqua Lifter-Dosing Pump aren't good for dosing. They have nearly no pressure when it comes to liquids. If you were to use them, they'd have to be on the same level as the rim of the tank to pump liquid.
This is good to know, I actually was planning on trying them and luckily I'm dosing in-line under the tank so it would be ok. I won't have much head pressure.

g
 
#15 ·
Great project! I used to use a perastalic for makeup water on a reef tank. It worked very well but I bought too small of tubing and it ran probably 12 hours a day. The plastic around the bearings for the rotor wore out and the pump stopped pumping after about a year. If you can limit the pump run to an hour a day or so by selecting the right size tubing and motor speed they should last long enough to be economical. Thanks for posting!
 
#16 ·
Curious about your timer settings and how you have regulated your dosages? How long do you run each pump for and how accurate is each dose? I see you mentioned the tubing used is good for about 0.9ml/min of flow...should I assume then that for a 10ml dose you have your timer set to 11.11111111r minutes??
 
#19 ·
Sorry, haven't been on much to answer questions!

ok, problem number 1 cropped up... the flourish line got clogged! the stuff dried up at the tip after a while and that was the end of that. now i just make sure i look at it once a month to make sure it stays clean. I just poke a paper clip in it to keep it clean. it only crusts up right at the very end, thankfully. i've also started to dose flourish twice a day now... MAYBE that will help it from crusting over so quickly? we'll see. but my lamp timers can have two on/off periods, so why the heck not run it for a few minutes in the afternoon? :)

as for the 0.9ml thing... to be honest, i just guestimated as close as i could. and then when my plants showed signs of deficiencies, i bumped up the time. i kept taking readings to make sure i wasn't poisoning anything. but my nitrates, nitrites, ammonia, and phosphates all stayed low, but present. the nice part about it is that it gets added DAILY (or twice daily if you feel like it). so if you have one or two stem plants that you can watch, you can tweak settings that way. AND on top of that... you always have your water changes to save your butt!

actually, there is one downside i'll mention... it makes you lazy. and mistakes happen when you're lazy. i stopped monitoring the tank for a bit, and the PH dropped. Why? because my KH dropped to nothing! I've never seen it before. i've even gone for like 6 months without water changes on tanks before and never noticed it. suffice it to say, i'm recovering from it.

as for the price of the pumps... brace yourself... i think they were about 70 bucks a piece (ball park). So with 6 pumps, you can see how the price would add up quickly! then again, i think most people would probably use 3 or 4. but then again... there are people on this forum with 200 gallon gardens, and they may consider 500 bucks for a robust auto-doser to be a valuable investment!

i think next time, i may go with larger diameter tubing. the current tubing is fine, but as one member pointed out, the fewer rotations the pump has to make, the better. on the bright side, the tubing that gets squeezed can be easily replaced (and the bearing and roller assembly too, i think). so... when the thing fails in 2 or 4 or 10 years or whatever, i'll happily spend 50 bucks and replace the wearable parts and continue on with life.
 
#20 ·
www.aptinstruments.com is the website. the model i picked up was SP100 FO (fixed output). it's under the OEM pump section. they also sell better-looking ones with housings and stuff, which did not interest me.

as for the in-line dosing... that would be interesting. i considered it, but decided against it BECAUSE... i figured the water in your tank has STUFF in it, and it will grow back into the tube most likely. by having the fertilizer DRIP into the tank, it guarantees that algae and whatever else cannot get into the tube. as i've already found out... a tiny amount of build-up in the tube will block it off, so i'd be wary of that. however, if anyone else actually wants to do an in-line or has already done something like that, please post your feedback!
 
#23 ·
because to dose 6 liquids, it would have cost 720 bucks. instead, mine was about 500 i think. i wouldn't quite call that similar in price. :)

also, the programming is apparently a little odd, and the thing goes bonkers when there is a power outage and needs to be reset (or slap it on a battery backup). the crappy little lamp timers i used have small batteries in them so short power outages are already covered. so even if the price was exactly the same, mine works how i want it to, with a large degree of flexibility. priceless to me!

sometimes off-the-shelf stuff is worth it; but for some of the people here who have the capability to slap their own stuff together, it's good to see how it can be done. gives them a bit more freedom to set things up exactly how they'd like them to be.

why build a canopy? why build a reactor? why do any of these things on your own?


...because you can :)




on a side note, the first "problem" crept up. the self-adhering velcro strips i used... don't use them! the timers get luke-warm to the touch, which keeps the adhesive gummy. the timers started falling off the door recently (what has it been? 5 months or so?). so i hung corner brackets from the door and gravity shouldn't be a problem anymore.

lesson learned = no sticky velcro!
 
#24 ·
just a little side note on the use of positive displacement pumps and neoprene hose. i work in a restaurant where these kinds of pumps are used for sauce portioning. managing a consistant portion is crucial to our product quality, therefore we have to calibrate these pumps daily. granted, our sauce pumps are much larger that the ones you are using for ferts, but i imagine you will run into the same kinds of issues. we use 3/4 inch tubing in our pumps. anyway, you will find that you will have to constantly increase the time that the pump runs in order to keep the same dose. for example, we have to change out the neoprene hose that comes in contact with the cam about every two to three months. if we don't, the hose bursts and we have a mess to clean up. when the hose is new, it only takes 2.5 seconds to move 10 oz of sauce. within a couple of weeks, that time will increase to anywhere from 3.5 to 4 seconds for 10 oz. by the time we change out the hose, i've had timers set up as high as 5.5 seconds for 10 oz. so keep an eye on your dose. and if you do ever change out your hose, be ready to cut back on time.
i do love the idea of not having to worry about dosing everyday. in my quest for automation in the tank, i'll definately keep this idea in my pocket. excellent read.:D
 
#25 ·
i will definitely have to keep this in mind. i'm HOPING that my application will out-last a commercial restaurant's sauce-delivery system. i'm running the pumps for 10 to 20 minutes per day usually, so i'm assuming the tubing will last longer. so far, so good. still tweaking fert quantities, trying to get them as "right" as possible; but that's no fault of the system. it puts in exactly how much i want, and when i want it; i just have to figure out what those magic numbers are!
 
#27 ·
After reading this thread, I thought that you might like to know about the experiment that I have started. I wasn't sure if I should start a new thread, but I finally decided to just reply to this one. My apologies if that decision was incorrect.

I too have been guilty of being too lazy to get up and go fertilize my tank. However, far more often the problem has actually been that I wasn't home to fertilize. For instance, a few weeks ago I went on vacation to Hawaii for two weeks. I was really concerned about the consequences of not fertilizing for that long, so I decided to have my in-laws to do it for me since they would be dropping by to feed the dog and check on the house anyway. However, I was also concerned about the in-laws not measuring correctly, so I had to measure out the ferts into individual containers with explicit instructions so the likelihood of messing up was minimized. I use PPS-pro, so that meant I had to come up with 28 containers for all of the pre-measured ferts. After going through that, I decided that enough was enough. I had read some of the other threads on APC about how others had tackled this problem, so I already had some ideas.

I also want to mention that laziness and absenteeism aren't the only reasons that I have wanted to automate the fertilization. I'm not a scientist, but logic tells me that most of the environments that our plants are from are probably relatively stable. I realize that rain storms occur and probably change the water parameters some, or maybe even in some cases, a lot. That being said, I doubt that in nature the plants have to deal with getting all of their nutrients for an entire day every morning before the sun comes up. They probably are more used to having the nutrients slowly leached into the water all day.

So for both of these reasons, I decided I wanted a system that would slowly drip the fertilizers in continuously. I wanted it to be accurate, dependable, well-made, and as fail safe as possible. I also didn't want it to be visible, since my aquarium is in the den of my house.

I looked at the enteral feeding pumps that are used to feed people through a tube directly into their stomach, but I decided that most of the ones available aren't designed for the extremely low rate that would be needed. They also aren't designed to pump against any back pressure, so I was concerned that they wouldn't be able to lift the fluid from down in the cabinet to up over the edge of the tank. On top of that, the ones that were capable of the low rates go for a lot on eBay ($200 or more, each).

Then I came across the infusion pumps that are used by hospitals to inject fluids into the bloodstream. These are capable of very low rates (as low as .1 mL per hour), are designed to pump against blood pressure (the one that I bought will raise the pressure up to 10 psi before sounding a warning that the tubing is clogged), have a built in battery to protect against power outages (mine will supposedly run for 4 hours on the battery if dosing 125 mL per hour, and even longer if dosing at lower rates), are computer controlled and programmable, and on top of all that, they are made to be used on people, so they are very well made.

After researching the best that I could, which involved intensive internet searches, talking with a cousin of mine that is a nurse, and also calling facilities that service these pieces of equipment and asking to talk to the service technicians that know the most about them, I decided that getting one of these would be worth trying. Then I just had to figure out which one to buy. That decision came down to mostly economics. Keep in mind that most of these pumps are several thousand dollars when new (I found out that hospitals don't even buy them; they lease them). However, there apparently is a pretty big market for older models that have been taken out of service, especially on eBay. To make a long story short, I chose the IMED Gemini PC-2TX pump, which is actually two pumps in one. With this one unit, I can independently pump two separate fluids, which made it perfect for PPS-pro usage. Here's a link to a site that has some information about the one that I bought:

http://www.firstbiomed.com/catalog_mfg_item.aspx?equip_id=103&id=2&key=equip_therapy_id

I managed to get an exceptional deal on eBay (I paid less than $52 total), but even so, there are plenty out there for less than $100 including shipping. Then the only thing you would have to do is get the specialized (and required) tubing sets that go with the specific pump that you buy. That, I have found, is considerably more difficult to do than buying the pump. However, the infusion sets do appear on eBay occasionally, but as I said, they are specific to the particular pump that you buy. Fortunately, I was finally able to get a supplier convinced that I wasn't going to use these on people and was able to buy four sets for about $45 (everyone else had said that I would have to have a license to buy them). Therefore, I have invested right at $100 for my system, and in theory, should only have to replace the tubing sets every so often (that's why I bought four; I have a spare pair when the first pair splits).

I decided to mix up my PPS-pro solutions at one-half strength, so I just used two liters of water instead of one liter. The only difference is now I dose twice as much. I have a 75 gallon tank, so I set both pumps to infuse at .6 mL per hour. It's been going for almost a week now, and so far I haven't experienced any problems. I have no idea how long the tubing sets will last before they develop splits, but I'm hoping that they will last a really long time.

Right now I have the hoses on the suction side just sticking down into the bottles of solution. However, I am planning on getting some graduated containers to put the solutions in so I can compare the actual amount left in the containers to the amount that the pumps say they have infused (I did some test with the pumps before I actually started using them on the aquarium to check the accuracy, and even though it wasn't exactly the same, it was within a mL after 24 hours, and I can always change the programming if necessary).

I hope this information has been helpful. I would be happy to provide pictures and more information if requested.

Andy
 
#28 ·
The following is in response to a PM that I thought others might like to read:

intermediate_noob said:
That was a great post, thank you very much for putting it up on the forums. If you would not mind me asking a few questions about this as I have always toyed with the ideas after reading about these pumps a year or so ago.

  1. Why did you mix your PPS-pro solutions at half strength?
  2. Do you find that you have a lot of precipitate in your containers? (Especially for the macro ferts)
  3. What kind of heights can these pump to, or do you have them pulling the liquid from under your tank?

I would appreciate any answers you might be able to provide. Thanks again.
Hello,

Thanks for letting me know that you liked my post. You are the first one to take an interest. I figured when I posted what I was doing with this pump that lots of people would be excited, but that hasn't been the case. Maybe there aren't as many people interested in automation as I thought.

I'm still in the experimentation phase of this project, so it's a good possibility that things might change, but I'm happy with how it's going so far.

I'm going to have to break my response up into pieces, since after typing it up and trying to submit it, I received a warning that the text was too long, so here's part 1:

I had two thought processes that led me to the conclusion that I should try mixing at half strength. I had always fertilized using fertilizers sold for aquariums, most recently with the Flourish line from Seachem. I was having a very difficult time achieving the "recommended" amounts of NO3, PO4, and Fe using these products. I started buying the dry ferts and experimented with adding them in order to achieve the proper amounts in the water. The plants started doing much better, but I found myself testing the water a lot in order to fine tune the amounts of the ferts to add. This became a pain, so I researched other methods. I decided that the PPS pro method sounded like the best option, since I like to enjoy my tank, not constantly work on it (don't get me wrong, I enjoy trimming the plants and doing the occasional water change, but only about every 2 to 3 weeks). When I mixed up my first batch of PPS pro, I noticed pretty quickly that the macro solution would get a precipitate that would settle to the bottom, and I would have to shake it up every time that I fertilized. When I got this pump, I figured that if there was more water, there would be less of a chance that a precipitate would form. I went with twice as much water since that makes the calculation for dosing really simple. I am no longer having the problem with the precipitate forming (which answers your second question). Another reason that I thought this would be a good idea was for better fine tuning of the fertilization. The infusion pump is capable of flow rates as low as .1 mL per hour. However, I wasn't sure exactly how accurate it would be. Granted, it is a medical device, so the technology, fail safes, and accuracies have to be very good, especially considering how quick people are to seek legal action in today's society. None-the-less, I figured that it might be more accurate at slightly higher flow rates (I don't have any info that proves that, it just made sense to me for some reason). Since my tank is 75 gallons, according to the PPS pro system, I should dose 7.5 mL per day (only a little more than .3 mL per hour). Since I mixed my solutions with twice as much water, I have been dosing at .6 mL per hour (which is 14.4 mL per day, instead of the instructed 15 mL, but I decided to go with the slightly lower amount for now). With the solutions mixed at half strength, it will be much easier to tweak the amounts added to the tank (although I have been so busy over the last few weeks that I haven't really had a chance to get into that too much).
 
#29 ·
Part 2:

I started using the PPS pro system in March, and quite honestly, have been so busy since then, that I haven't been testing the water parameters to see if I needed to tweak how much I have been adding (I guess I just trusted the system so much that I felt like I could get away with not testing as much as I had been). I installed the infusion pump on August 1st with the initial setting of .6 mL per hour, using the new batch of PPS pro mixed at half strength. On August 16th I tested the water for the first time since March, and was shocked at my findings. The Fe was at .1 ppm, PO4 at .65 ppm, and the NO3 was at 50 ppm(the test kit only goes to 50, so for all I know it might be higher than that)! This actually doesn't have anything to do with the infusion pump itself, but more to do with PPS pro, since I'm basically dosing the same, if not a little less, than I was before by just measuring and pouring. Since the Fe and PO4 are within acceptable limits, I don't think that I will adjust the dosing amount yet. I have been having a pretty bad issue with BBA, but it has been dying off for several months now. When it dies it lets go of whatever it is attached to and then gets sucked into the filters. I haven't cleaned the filters since June (and when I did they had huge amounts of decomposing BBA in them), so I'm hoping that the elevated levels of NO3 are just from dirty filters. Once I clean them and do a water change I'll start checking the water parameters more often so I can see if the dosing amounts need to be changed.

Your last question will be more difficult for me to answer. I haven't been able to find specifications that say exactly how much head height this pump is capable of. However, when trying to decide between an enteral feeding pump and an infusion pump, I just used my own logic to decide that an infusion pump would be better (which very well might be all wrong). For instance, I saw this thread for automatically dosing a reef tank: http://www.aquaticplantcentral.com/forumapc/diy-aquarium-projects/59525-automatic-continuous-feeder-diy.html . It got me really excited about trying something like this, but the more I looked into enteral feeding pumps, the less that I thought that they would work. For instance, most of them are only able to go down to 1 mL per hour. The EnteraLite Infinity pumps that SantaMonica used for his reef tank are able to go down to .1 mL per hour, but they are expensive. In fact, I watched some on eBay for weeks hoping to get a good deal, only to see that they always go for way more than I was willing to spend. I just checked completed listings for the last 30 days, and the cheapest one sold for $248.50, with one going up to $350.00! Since I needed two of this style pump, I abandoned it as an option. On top of that, even if it was cheaper, the instruction manual for that pump states that it maintains a +/- 5% accuracy, but only if the head height is +/- 12" from the center of the rotor. I was concerned that this would be a problem, since my pump is sitting in the bottom of my cabinet, and the tubing rises about 53" before the fluid drips out into the water.
 
#30 ·
Part 3:

SantaMonica had his pumps sitting on top of the tank. One thing going for him was that an enteral feeding pump is designed to pump thicker liquids, and since he is using it to feed corals, that was an advantage. I don't know a whole lot about what types of liquids an infusion pump would be normally used for, so I don't know if they are capable of pumping thick liquids or not (the instruction manual for my pump states that it can infuse "intravascular drugs, fluids, whole blood, and packed red blood cells"). My thought process was that an enteral feeding pump is just pumping a fluid into your stomach, but your stomach isn't trying to pump anything back out (my theory might be flawed, so those in the medical field, please don't yell at me). I figured that since an infusion pump is for pumping liquids into your blood stream, and that your heart is developing pressure too, that an infusion pump would be better since it is designed to work against that pressure. I don't know if the thick liquid/no pressure property is comparable to the thin liquid/backpressure one or not, but my theory was that an infusion pump would be best. In the three weeks that I have had it set up, I haven't had any problems at all. The pump has the ability to check for air in the hoses and for an occlusion (blockage), but it hasn't alarmed yet, and at this point, I doubt that it would. Every time that I have looked at the ends of the hoses where the fluid drips out, there is always a drop sitting there waiting to get big enough to fall, and I've watched them drip in (although I haven't timed how long it takes between drops, but it's quite awhile). I was somewhat concerned that I might end up with a crust forming at the ends of the hoses, but that hasn't been an issue (I don't have the hoses below the surface of the tank water because I don't want to siphon out the tank water in the event of a hose failure). Besides, I think that the pump would be able to develop enough pressure to push it off anyway.

I hope that this information has helped you. I have communicated with the company that I bought my infusion pump from, and they said that they have many more of them. It is possible that they might be able to work out a deal for others from APC, but I can't promise that. Even so, there is another eBay seller that has 50 available using Buy It Now for about $85 including shipping. There is also someone with a couple of cases of the infusion sets that we could possibly buy and then distribute to each other. I am still using the first pair of tubing sets, and my plan is to continue to use them until they develop a leak, just so I can see how often they should be replaced.

It took me several hours to compose this reply, so I’m going to post it in the thread as well in case others might benefit from the information. I’m subscribed to the thread with instant email notification, so I’ll see if you post any more questions on the original thread. That way we might can get more discussion going.

Andy
 
#31 ·
Thanks so much for putting this up, I think that it is a great idea for DIY! Another quick question, did you say that you only need one pump for both of your PPS-Pro solutions so that 85 dollars would all that it would take (besides the infusion tubing sets)?

Let me know about this, and if you could post links to the eBay seller and the infusion sets I would appreciate it.
 
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