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CO2 newbie with questions

1K views 12 replies 6 participants last post by  yobofofas 
#1 ·
Today, after talking to a knowledgeable and very helpful LFS employee I decided it's time to look into CO2. Mainly because it works. They have an amazing 90g tank that is beautifully overgrown and I want the same.

So I hit the Doctors Foster and Smith site and ordered this. I can pick up a 5 gallon tank at a local hardware store so I figured, why not? My question is, without using a PH controller, whats the best way to monitor my CO2? Is it purely bubble count? And if so how many per second for a 90g tank? I'll be running the system with my light timer, which seems to be the best idea, but it almost seems to easy. Do I need to worry about a PH controller or a reactor?

Any help will be greatly appreciated.

Thanks
 
#2 ·
It will help you get started well if you buy a "drop checker", search in ebay for "CO2 checker". There are several different shapes, but all of them work the same. It is best if you get some 4 dKH water, made for this use, from someone here on the For Sale forum. Then, add that to the bulb of the drop checker and add a couple drops of the blue pH test kit reagent - like that which comes with the API pH test kit. The solution should then be blue. Add the drop checker in the tank so the bell mouth is facing down, trapping air in it. Wait a few hours, and the solution will be green to yellow green if you have a good amount of CO2 in the water. If it remains blue or blue green, increase the CO2 bubble rate. If it gets real yellow, you will probably need to reduce the CO2 bubble rate to avoid harming the fish. This isn't an exact way to measure CO2, but there is no exact way without spending $1000's for a test probe.
 
#3 ·
You do not really need a pH controller to control your CO2, though it is a nice luxury item to have if you have the extra money.

You can monitor your CO2 in a variety of ways; bubble count is one, but it is quite subjective, as bubble size can vary depending on several factors.

You can use a drop checker to estimate your CO2 levels, though their reaction times are quite slow (at least a few hours).

Of course, without either of these methods, you could simply start by injecting CO2 and watching your livestock for any signs of CO2 stress; if they are exhibiting such symptoms, then you back off the CO2.

A reactor/diffuser will be required for efficient dissolution of CO2 into your water column. For a larger aquarium such as yours, I would recommend a reactor.
 
#4 ·
I find monitoring co2 with a couple of drop checkers, and doing a ph / kh test to compare with the chart helps too. Neither is an exact science but combined they haved served me well with a 125g high tech setup.

As for diffusion, you might want to split the co2 feed from the regulator (with two bubble counters and needle valves) to the tank and maybe have two reactors, or one with tons of flow. For a tank that size I wouldn't bother with anything other than a reactor.
 
#7 ·
I was looking at this one but If I don't need to spend that much I wouldn't hate it.

I'm wondering, could I tie this into my sump return? I can't think of a reason it wouldn't work.

Otherwise I'd love some reactor suggestions.

Thanks all.

mb
If you got a sump, you can just feed the co2 into the return pump and have the pump chop up the bubbles. Just seal the top of the sump to avoid co2 from dissipating. If you want to do the reactor, I would use a canister.
 
#8 · (Edited by Moderator)
That looks very do-able and waaay cheaper!

You guys have really been helpful and I can't tell you how much I appreciate it.

If you got a sump, you can just feed the co2 into the return pump and have the pump chop up the bubbles. Just seal the top of the sump to avoid co2 from dissipating. If you want to do the reactor, I would use a canister.
It's actually a refuguim so I need it open. When you say canister, can you link me to some examples?
 
#9 ·
#11 ·
If I were to build this reactor, and I'm thinking I will, it would be connected to my return line coming out of the refugium. Correct me if I'm wrong but my pump runs to my reactor, reactor to spray bar return. This should take care of any outgassing. Yes? But now that I'm thinking about it, you're saying that I'll lose CO2 when the water returns to the refugium? Will I really lose that much? Won't having my reactor feeding directly into the tank be enough. I'm not doubting you and appreciate all the info, just curious.
 
#12 ·
=yobofofas;4261969]If I were to build this reactor, and I'm thinking I will, it would be connected to my return line coming out of the refugium. Correct me if I'm wrong but my pump runs to my reactor, reactor to spray bar return. This should take care of any outgassing. Yes? But now that I'm thinking about it, you're saying that I'll lose CO2 when the water returns to the refugium? Will I really lose that much? Won't having my reactor feeding directly into the tank be enough. I'm not doubting you and appreciate all the info, just curious.
The CO2 will gas off anywhere it can. Especially on the return (with all the splashing etc) and you got to seal the sump. Some folks have had success raising the level of water in the overflows, & going with a venturi co2 feed, either through a mazzei injector or a needle wheel pump. Look up durso standpipe, here is an example of an overflow used in planted tanks that works better.

 
#13 ·
I've got a Durso standpipe and this could work. Although I'm thinking it would make more sense, for my setup, to hook up the reactor inline with my return so the CO2 enriched water goes straight into my tank. Rather than into the sump first and then the tank.

Thanks for the diagram. Even more to think about, hmmm...
 
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