Baseline Ph Level For Injecting Co2 Help

Wes chancelor

New Member
Apr 25, 2020
I e searched as many forums and posts as my brain can handle and can’t find the answer to my question. I’m sure it’s been talked about somewhere in-depth but...

Starting co2 injection and want to know How
to calculate co2 levels which of the following should I use for my ph baseline:

Tap water? 7.4

Tank water sample that’s been out of the tank for 24hours? 7.2

Or tank water inside tank with co2 off and airfares overnight? 6.8

My kh is 1.5

Thanks in advance for your help. I’ve learned so much form this site!!!

Also if note I’m using Aquasoil Amazonia which buffers the ph a bit. Tank has been up for a month and currently using diy co2 which gets my drop checker a nice green and gets ph down to 6.4 fish and shrimp seem to be doing good and only some diatoms.


Super Moderator
Staff member
Lifetime Member
Jun 20, 2016
Hello and welcome. Your tank looks nice and healthy.

The idea behind the tehnique is to use the 'degassed' (as in at equilibrium with the atmosphere) aquarium water as a base level and target a 1 drop in pH. Make sure to clean up the cotainer that will hold the water so that there are no mineral deposits on it.

With a KH of 1.5 and aquasoil you might need a little more than 1 drop in pH to actually get aroud 30 mg/L (ppm). So if fish are okay don't be afraid to push it a little bit more. Just wash the fish.