# How to get CO2 to 30ppm



## Yeaulman (Jun 23, 2005)

I had just picked up a CO2 drop checker and mixed up the proper 4dkh solution from distilled water and a trace of baking soda. I have then added a few drops (extra also to make it darker) of the ph solution. I have my CO2 on for 10.5 hours during the day and cannot get the solution to go from blue to green.

My tanks specs are as follows:

90g with 65w x 4 6700K PC lighting (1st 2x65w bank on at 12pm with CO2, 2nd 2x65w bank on at 12:30pm; 1st bank and CO2 off at 10:30pm, 2nd bank off at 11:00pm)
XP3 filter
ADA Bettle knockoff diffuser
3-4 bps of CO2
KNO3 and KH2PO4 mon, wed, fri
CSM+B tues, thurs, sat.
50% water change sunday
very little surface aggitation


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## hoppycalif (Apr 7, 2005)

A 90 gallon tank will probably take more than 3-4 bubbles per second of CO2 to reach 30 ppm, especially if you are not using an external reactor that gets 100% of the CO2 dissolved into the water. I used to use about that much CO2 on a 29 gallon tank! The in-tank diffusers that generate fine bubbles are effective, but not as effective at using every last bubble of CO2 as a good external reactor is. I was using a powerhead with the CO2 going to the inlet of the powerhead when I was using so much. And, I was after a CO2 mist, so I expected to use a lot of CO2.


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## Bert H (Mar 2, 2004)

Do you have hard water (high kh)? If so, you will have problems achieving and maintaining 30ppm using a timer controlled solenoid. I run my CO2 24/7 after realizing I couldn't attain my desired CO2 levels with a solenoid. I have hard water at kh 10.


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## Yeaulman (Jun 23, 2005)

I'll have to check what my current kh is at.

I looked at our cities website and found that our hardness is 126 mg CaCO3/L.


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