I time the CO2 to come on/go off about 30 mins ahead of the lights.

 

I'm running 24x7 pressurized.

 

Well I use DIY Co2 so I have to run it 24/7. If I ran pressurized Co2 I would time it because running co2 at night is a waste because plants don't use it anyway.

 

Very interesting that just as many people run 24/7 as do time the CO2 to come on just before the lights. I was not expecting that, but I would assume that most of the 24/7's are DIY except for Paula?

 

I do 24/7 as I have a 75-gal tank and am using a ceramic disc diffuser. I found that I have a steadier CO2 level doing 24/7. I have a very good needle valve and am able to get a very reliable bubble rate. I have recently purchased a submersible powerhead which I will mount with the intake over the diffuser. This may make a difference in efficiency and how I handle/manage the CO2 injection.

I did try injecting directly into my 2028 Ehiem filter inlet and timing it with lights on/off but this caused disasterous algae issues.

 

I run co2 24/7 with a Redsea paintball regulator and 20 OZ tank in a 46 gallon bowfront. Since $5.00 worth of gas lasts 4 to 5 weeks, adding another timer and soleniod isn't worth it to me. Also, I don't have to worry about ph fluctuations since my tap water has a kh of 5.

 

Well, that does it! I'm going to 24/7 as well. Every time my solenoid shuts off and then back on (like, EVERY DAY) I have to re-tweek my needle valve.

Newt, I had mine hooked up to a powerhead also until recently. I found that the ceramic disc I just got is far more efficient at dissolving CO2. I was pumping 4 bps in my 55 with the powerhead. With the ceramic, I'm doing half of that and getting the same pearling, and when I try to get over 2bps the fish really start stressing out.

 

Newt, I had mine hooked up to a powerhead also until recently. I found that the ceramic disc I just got is far more efficient at dissolving CO2. I was pumping 4 bps in my 55 with the powerhead. With the ceramic, I'm doing half of that and getting the same pearling, and when I try to get over 2bps the fish really start stressing out.

I was still going to use the ceramic disc. I am going to place it under the intake of the powerhead. I am hoping this will help circulate the CO2 around the tank and help dissolve it more by having it in contact with the water longer. The ceramic diffuser is quite inefficient as many CO2 bubbles just rise to the surface and escape into the atmosphere. I will have the powerhead on the timer with the lights.

 

CO2 w/solenoid. Co2 at night is waste. The pH drops naturally at night so the pH variations with solenoid is minimal in my case, I have Discus and never have pH problems.

 

This is what I am currently doing, too.

 

So if you run the CO2 24/7 do you need to pump in air at night since you plants are not photosynthesizing with the lights out?

 

I hope not. I'm going to be counting on slight surface agitation and mediocre diffusor efficiency, with a reduced CO2 rate than what I normally pump in.

 

I dont and my fish show no ill effects. The pH only drops a little over night and the pH/KH chart says ~36ppm. When I used a solenoid and shut the CO2 off/on with the lights I was always playing catch up on the CO2 concentrations when it was lights ON and it would be late day by the time it got back to ~30ppm.

 

All ahead slow, steady as she goes.

 

I just wonder how that would work in my setting because my water has very low dkH (0 to 1 dKH) because I use RO/DI water that I reconstitute with RO right.

The only little bit of kH I get is from adding Brighty K everyday. I am thinking it might be OK based on this pH-dhK relationship http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm that suggests that CO2 should not build up to toxic levels for the fish. What do you all think?

 

My city water is naturally soft and the kH is also <1dkH and GH is ~1dGH. I add a GH mix of CaSO4+MgSO4+MnSO4 and an alkalinity buffer by Seachem so that my tank water is GH 5 and KH 3.

Those liquid mixes are not very good. I used to use ElectoRight and it does not contain what it says on the bottle and it also has aloevera in it. The msds gives the correct ingredients.

With a KH so low you will run the risk of dropping the pH is a very low level.

 

+1 on Newt's post. You can tune RO to what you wish with this, and this, and possibly this.

 

I have all that stuff but I ended up not using it. Equilibrium is a pain to dissolve. I use to powdered version of RO right http://www.marinedepot.com/ps_ViewItem~action~view~idProduct~KM5335~idCategory~FWADRO~category~RO_Supplements-Additives___Supplements-Freshwater_Aquarium_Supplies~vendor~.html together with a TDS meter to get to the water to soft-medium hardness (170-200 uS). Yes separate issue from dkH. I do have a little tub of Kent Marine pH stable which is probably NaHCO3 but I rarely remember to add it.

Going back to dave's original question. I am one of those people who has the CO2 on solenoid/timer and I "areate" my 60P at night by raising the lily pipes per ADA and Jeff Senske's advice. I wonder what happens to the dissolved O2 content when the lights are on vs off (regardless of fish) when you run the CO2 24/7. I know some of the NASH folks do this. Does the O2 content drop to hypoxic levels? If so would'nt this be bad for the biofilter? Dave if I give you this http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+4345+4366&pcatid=4366
would be willing to measure in you big tank?

 

Going back to dave's original question. I am one of those people who has the CO2 on solenoid/timer and I "areate" my 60P at night by raising the lily pipes per ADA and Jeff Senske's advice. I wonder what happens to the dissolved O2 content when the lights are on vs off (regardless of fish) when you run the CO2 24/7. I know some of the NASH folks do this. Does the O2 content drop to hypoxic levels? If so would'nt this be bad for the biofilter? Dave if I give you this http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+4345+4366&pcatid=4366
would be willing to measure in you big tank?

Bunbuku's question about O2 leads to another question.

Is it possible to have too many plants?

Consider this scenario:
A tank loaded with fast growing plants and a very efficient external reactor. The CO2 levels are raised to 30ppm during the day. The CO2 is turned off. The lights go off. Now you have fish competing with plants for available O2.

Observation: All of the fish are gasping at the water surface in the morning.

This scenario is definitely a sign of asphyxiation. What is the cause? Is it the plants consumption of available O2? Was it the high levels of CO2?

My favorite source of information, thekrib says this:

Your fish are going to get stressed only if CO2 increases TOO much
overnight or
the O2 is reduced TOO much overnight. Even with high oxygen levels, fish
cannot
respire CO2 unless the concentration of CO2 in the water is less than the
concentration of CO2 in the fishes blood. The exchange of O2 and CO2 in the
gills is determined by the relative concentration of each gas on both sides
of
the gill membrane and the exchange of each gas at the membrane is
independent of the other.

Many people miss this point. With high O2 AND high CO2 in the water, CO2
cannot
leave the blood (meaning O2 can't enter the blood; they bind to the same
site on the hemoglobin molecule) and the animal asphyxiates. With low O2
AND low CO2 in the water, CO2 can leave the blood but O2 can't enter and
the animal
asphyxiates.

Comments?

 

Two things we all need to realize about CO2 and O2.
(1) CO2 is 40 times faster at dissolving into water as O2 and 40 times faster at being released from water.
(2) CO2 does not displace O2 from the water.

 

Dave--did you ever move to 24/7 CO2? If so how did it go?

I have been running mine coordinated w/ the lights and am considering moving to 24/7 to get better consistency to (hopefully) defeat my ongoing BBA issue.

Thanks,

Roy

 

Roy,

I DID go 24/7. All is well, but I had to turn it down just a hair to keep the fish from gasping late into the night.

-Dave

 

if I was not going to use a PH controller.

I'd start it up about a hour before my light came on and have it trun off about a hour before it goes out.

 

Thanks Dave--I think I will try this as well--but wanted to see how your transition went first.

I run a split photoperiod to maximize my viewing time of my tanks and I think having the CO2 kick on an off is causing some fluctuations.

 

Dave, check out this link. It has a few pictures of surface scum and what they are caused by:
http://www.aquariumalgae.blogspot.com/

 

Thanks, Newt. Mine is what he describes as being casued by the iron-bacteria. I did improved my surface agitation a coulpe weeks ago, but it still has not been successful. I think that soil I have is the culprit, releasing more iron/micros than my tank can use unless I increase my light level (and then would have to increase my CO2 and macros as well).

I guess my main assumption there is that the rooted plants are getting all the micros through their roots (as my epiphytes look defficient in micros) and whatever my tap water has in it is either being used by alga or by these "Eisenbacteria". There is probably at least SOME leaching of micros into the water column, but obviously it's not enough to feed the Java Fern and Anubias.

-Dave

 

I had off and on surface scum. It was frustrating because I wanted to figure out the root cause but it alluded me. One week I'd have it, next no. For months no issues. Then all of a sudden for 3 weeks I get it. All this time little changing in my feeding, fert regime or filtering maintanence.

I tried it all: more surface agitation, black mollies, backing off on food, etc. Nothing worked consistenly.

In the end I jerry-rigged one of these up as a replacement of the standard intake of my Eheim 2028:

http://www.bigalsonline.com/StoreCa...27/cl1/fluval_surface_skimmer?&query=Fluval+surface&queryType=0&hits=12&offset=

It worked immediately and within 3 minutes my surface was a crystal clear and has been since. Yes, is can get some light leaf debris in the top intake that needs a quick cleaning, and the rod needs adjustment every few days or so if the lower intake gets leave litter but I'm one who enjoys and views my tank at least twice a day and the moment or two to do such once or twice a week is a small effort vs. the digusting milky, scummy surface, let alone the crustly and slimy ring such scum would leave alone the sides of my rimless and topless tank. All that is in the past now....I do not think I've even spend a better $15-20 bucks in this hobby...

 

I bury my anubias (coffefolia) in the substrate and get huge root structure and they flower all the time.

 

Does it take some water from a little lower down too, or just from the surface? Any detritus buildup in the tank if that isn't the case? I may have to get one of these. If I drag a ruler across the surface, it looks like pudding skin.

 

It has an intake similar to most on the bottom and the floating intake at the top. With evaporation, and if you have any leaf litter accumulate at the lower intake area, you may need to adjust the rod which changes how much water is sucked in the top or bottom parts, but as I mentioned I find this minor maintenance vs the trade-off of having milky pudding or crystal clear water surface.

 

Thanks, rich815. I just put it on my "to get" list. I have an Eheim 2217, so I guess I'll have rig it up as well.

-Dave