Naja002

True, but that is the kicker, I think:

X-amount of change in pH......

PPM stays the same though.....and that's what we are after....

Provided I am finally seeing this correctly!

Question:

I have made a DIY Drop Checker. It is bulky and I will post pix shortly. RODI Water set to 5Kh---How Much/Many pH drops do I add? Does it Matter? Do I need to measure the solution going into the Drop Checker and add 3 drops/5ml (AP Test Kit)?

Thanx!

hoppycalif

I experimented with the AP test kit, adding varying amounts of the pH reagent to tubes with the same water - tank water - in them. It made no difference to the results whether I used the three drops the instructions call for, or 2 or 6 or even 9 drops. With larger numbers of drops the result becomes a murky opaque liquid, where reading the color is harder, not easier. But, the color stayed the same for all. So, I just add whatever amount makes it easiest to judge the color.

Naja002

Hi Hoppy,

Thanx for the Clarification. I found the answer from some previous posts of Your's here:

DIY Drop Checker--Post #1

Which leads to here--More in-depth:

Does it work? ADA glass dropcheck co2 indicator--Post #25

Here's some Pix of the 1 I just made--Mind you, its cost was $0 (I had everything) and it's going into my A. javanicus setup--so, looks are not currently of utmost importance:

Parts:



Assembled--the top heater holder just goes above the bottle to help reduce the buoyancy-pull on the heater holder around the bottle neck:



Full:



Its an 8.45 Fl oz. "Kid's Connection Soda" bottle. I bought them at Walmart in a 4-pak for $1-2 and I use them for DIY C02 Bubble Counters. This one was an Extra. The PVC is just 1/2" and the bottle opening fits it like a glove--No glue, silicone, etc. It currently has about 95ml of RODI water set to 5kh w/ BS.

I added 114 drops of pH liquid--and its really too dark. I am going to install it an see how it looks under the light. But I will probably redo it with less drops. The water color is not Blue, but Blue-green--what does that mean? The RODI water was made yesterday and was putting out 0-2ppm TDS. The Gallon jug has just be sitting capped overnight. Any thoughts on that?

EDIT: I was afraid that the bottle body was just going to be too wide for the suction cup to hold--and it is. So, I have eliminated the suction-cups and tied 2--1 1/2 oz lead weights around the neck--dangling about 3" below the bottle. So, now it is a floating version.

Anybody know if the entire Drop Checker Must be below the water surface--like for pressure? I guess we'll find out in a few hrs!

I also redid the fluid mixture: 100ml and 10 drops of pH liquid. Now its a nice pretty blue and should be easy to read....

Thanx!

hoppycalif

The reason for keeping the entire device under water is to avoid any temperature difference between the device and the tank water. If there is a difference some distillation will occur - water will migrate from the warmer to the cooler area, which changes the KH of the tester water.

Are you sure there is no leakage between the pvc tube and the bottle neck? If so, that has to be the easiest one yet to make. (But not the most unobtrusive or most elegant or coolest!)

Naja002

Absolutely? Positively? Well, No, but as You can see in the pic above--there is no leakage onto the Towel. And in order to get the PVC pipe back out--I have to insert my finger, bend it to kind of Lock it in place, and fight and struggle for a bit. I can't guarantee that there will not be any osmosis at all, but its a solid fit. Time will tell, I guess!

I just got the fishing line back out and tied it to a rock that will reach the bottom yet keep the Checker below the surface. Its in my Plant Filter, so looks really isn't a Big Deal. Ghetto? Yes, but if it provides some benefit--I'll do it right later...After 4hrs of floating--the color didn't change at all (floating). According to the Chart: I have pH 6.0, Kh 2, so C02 should be around 60ppm. We'll see if the color changes now that its completely submerged.

Thanx!

schaadrak

Just a thought, but if the membrane idea pans out, these could be made even easier by gluing a piece of membrane to the top of any small clear container filled with indicator solution.

Like this:



It wouldn't matter which way was up since water can't go through the membrane and you could use any small clear container you have lying around with virtually no modifications. Heck, you could just glue membrane to either side of a piece of air line tubing. Then if it starts going bad, toss it out and throw a new one in.

hoppycalif

As I recall, the membranes are made of teflon or polypropylene plastic, and neither of those is at all easy to glue. Both are, I think, considered "release agents". If you can use glue, I hope someone with the knowledge will tell us which glue to use. If I had some membrane, other than Tyvek, which is very thick and stiff for something like this, I would just wrap it around a piece of tubing and rubber band it in place. I do have a pretty nice piece of transparent vinyl 1/2 inch tubing I could easily use this way. But, the first steps are to find a source of membrane, and to find out if there is a glue that will work with it.

EDIT: I did some googling and found the obvious source of membrane material - Kordon breather bags! Who has some and is willing to supply one or two to me - of course I will pay shipping and cost of the bag(s)?

EDIT AGAIN: It only took a few minutes to get two offers of these bags, and both are relatively local to me! If I can make this work out I will make two or three extras and offer them to whomever wants them. But, I hope someone else tries this idea too.

epicfish

Naja002 suggested breather bags already: https://www.aquaticplantcentral.com/f...her#post256349

=P

I think, for an effective drop checker using a semi-permeable membrane, you could overfill a test tube or container or whatever, and place the membrane over the top so that there is absolutely no air inside the container. This way, the dissolved CO2 within the tank can directly dissolve through to the other side and give faster results.

Of course, since CO2 in H2O yields carbonic acid, I wonder if these molecules will be able to get through the membrane...no time to ponder this for now. Final exam in 2 hours.

Naja002

The Breather bags are designed to let C02 out and 02 in--question is: does it go both ways?

In order to maintain equilibrium the C02 must be able to enter and exit as it changes in the tank. Guess that would be a question for Kordon.

My Ghetto Drop Checker changed colors since I completely submerged it. Its Green now, but hard to tell Which Green! I guess I'll add a few more drops of the pH liquid and see if that helps.....

hoppycalif

The reason the Kordon bags "let oxygen in and CO2 out" is the same reason it will work for the drop checker. The gas will always reach equilibrium conditions on each side of the membrane. So, if the fish or plants are using O2, the O2 concentration will drop on that side of the membrane and O2 will have a net inflow to that side. But, if the fish or plants release CO2, the CO2 concentration will increase on that side and there will be a net outflow of CO2. The membrane is little more than a net with extremely small openings, so it must be able to let gases go either direction.

If I were designing a membrane drop checker for sale, I would have a sheet of membrane with 4-5dKH water and pH reagent spread on it, lay a second sheet on top, then heat seal a grid of 1" squares, so it separates into a bunch of 1" square pillows with standard KH water/reagent sealed inside. One of these could just float in the aquarium - it would have near neutral buoyancy.

So, who has a machine that does this - seals two heat sealable plastic sheets together in 1" squares? Surely one of us has one hidden away in the garage??