Co2 control - The Planted Tank Forum
LinkBack Thread Tools Display Modes
post #1 of 5 (permalink) Old 03-01-2006, 08:13 AM Thread Starter
PTrader: (0/0%)
Join Date: Apr 2005
Posts: 5
Co2 control

Hi There,
I have a 100 gal planted tank, and the Co2 is controlled by an aqua medic Ph controller is this the correct way of doing it ?. And what should the ph be set at ?.
chippypah is offline  
Sponsored Links
post #2 of 5 (permalink) Old 03-01-2006, 11:29 AM
PTrader: (0/0%)
Join Date: Jan 2006
Posts: 7
Smile i have a 55g

with a Milwaukee PH controller, i run mine at high 6.8 to low 6.9. i use a co2 ph chart to find out my co2 ppm. in my tank the KH is at 7 and with a at PH 6.8-6.9 my co2 is at 26.437ppm. (i got this info at
there is a lot of great info on these pages.
D&E Aquatics is offline  
post #3 of 5 (permalink) Old 03-01-2006, 07:38 PM
Planted Tank Guru
PTrader: (84/100%)
Join Date: Dec 2005
Location: Sacramento, CA
Posts: 21,012
The PH controller is just one way to control the CO2. Even with the PH controller you need a needle valve to adjust the bubble rate - if it is too low, you will never reach the PH you select, and if it is too high the PH will overshoot by too much when the controller shuts the CO2 off. You still need to periodically measure the KH and make sure the PH you have selected gives you the ppm of CO2 you want. If the KH varies, the ppm of CO2 for a given PH will also vary. Personally, I prefer to do without the controller, and just manually set the bubble rate so it holds the tank at the ppm of CO2 I want, then use the solenoid to shut off the CO2 when the lights go off.

Hoppy is offline  
post #4 of 5 (permalink) Old 03-12-2006, 05:29 PM
Planted Member
Riche_guy's Avatar
PTrader: (0/0%)
Join Date: Feb 2006
Location: Montreal, Canada
Posts: 236
I hooked up a pressurized CO2 tank with Rex CO2 reactor I didn't know the concentration or how to go about it. Checked out D&E Aquatics's post above which led to Chuck's Planted Aquarium page which was a god send for me. After checking my Ph realized it had fell to 6.4 and my Kh is 2 or 35.8 ppm. My CO2 count following his chart is 24ppm which is in the green and good. I just hope my Aquarium Pharmaceutical test kits are accurate enough.

110 gallon Discus tank
65 gallon Discus tank
30 gallon Discus tank
20 gallon standby tank
10 gallon quarantine
Riche_guy is offline  
post #5 of 5 (permalink) Old 03-12-2006, 11:22 PM
Planted Tank Guru
PTrader: (84/100%)
Join Date: Dec 2005
Location: Sacramento, CA
Posts: 21,012
When KH is as low as 2 you can improve your accuracy a lot by using twice as much water as the test tube calls for - I just fill the tube twice and dump in it a small and thin wine glass. That way each drop equals 1/2 degree of hardness instead of one degree.

Hoppy is offline  


Quick Reply

Register Now

In order to be able to post messages on the The Planted Tank Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome