# Co2



## sparkyr99 (Jan 9, 2011)

I finally got my co2 setup turned on. Now for the silly questions: At what level should my Ph be? Without co2 injection its 7.2. with the co2 on it drops to 6.4 to 6.6. I've been testing in the morning before it comes on and in the evening right when it goes off. My range (average) for the last couple of days has been 7.0 to 6.6. Is this too much of a shift? Ideally what would should the range be? The co2 is on the timer with my lights and i've been using a split lighting period, 7am to 11am / 2pm to 9pm. on a 120 gallon with about 2 bubbles per second. thanks , steve


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## susankat (Nov 15, 2008)

Sounds about right. Should be fine. Just keep an eye on the fish to make sure they aren't up the top gasping.


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## jrman83 (Jul 9, 2010)

That should be fine. Mine shift right at 1 full point....from about 7.7 to 6.8 in only a 6hr period and all my fish do fine with it.

TBH, I rarely check my ph (not saying you don't need to). I just look at my drop checker and drive toward green. I know that going from blue to a light green green is about 1 full point of ph and gets me close to 30ppm of CO2.

Do you have a drop checker?


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## majerah1 (Oct 29, 2010)

I have a question as well.My fish will stay near the top,yet they are not gasping.The ph is at about 6.0.It was at 7.0 before so it did drop a full point.Is it still too much?I have it going at less than 1 BPS.No drop checker yet,its not in the budget just yet.


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## sparkyr99 (Jan 9, 2011)

No i don't have a drop checker. I was under the impression that a drop checker was just another way to measure ph.


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## jrman83 (Jul 9, 2010)

sparkyr99 said:


> No i don't have a drop checker. I was under the impression that a drop checker was just another way to measure ph.


Drop checker measures CO2 content and has noting to do with ph. Very important to have if you have pressurized CO2 for the safety of your fish. It's a quick and easy visual check that your CO2 is good or danger.


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## Gibby (Mar 24, 2011)

CO2 Indicator

I use something similar to this cheap and measures the CO2 levels.


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## jrman83 (Jul 9, 2010)

That is one of the many forms of drop checkers out there. I prefer the nano glass style myself, but they all work pretty much the same. There are also numderous DIY videos on youtube.


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## Gizmo (Dec 6, 2010)

My CO2 moves my pH between 7.2 and 6.6 on a daily cycle, with 6-8 degrees of KH at any given point.

pH and KH are interrelated - a high KH will cause a smaller pH swing because it buffers the water against said swing. However, fish and shrimp can only tolerate so much KH.

Drop checkers are by far the most accurate way to measure CO2 concentration in the water because CO2 is not the only thing that affects the pH-KH relationship, so the algorithms used in the pH-KH relationship aren't always accurate. Plus, drop checkers are not expensive at all 

Fish swimming near the surface might be their personalities. My black stripe tetras stay in the upper water column while my bloodfin tetras stay deep, for example.


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