How low is low?

Hi folks,

Two weeks after starting EI I am having major problems with Fuzz and Green Spot Algae. Following the advice on this site, I have reset the tank & I am starting fresh with dosing, and at the same time increasing CO2 levels.

I feed the CO2 in the inlet of my Eheim 2217 and I have been slowling increasing the levels to see when the fish start gasping, which has not yet happened.

I have measured my KH with two different kits and they read 4 & 5 respectively. With the gradual increase in the bubble rate my pH now hits a low of 6.3 about 6-7 hours after the CO2 turns on in the morning (a lot of small bubbles are now coming out of the spray bar) & it slowly moves up to 6.6 during the night after the solenoid has been shut off, but the fish show no sign of stress.

My question is, how low can I push down the pH without adversly affecting the fish/plants? If I want to keep increasing the CO2 until I see the fish gasping before I turn it up a notch, I may have to go lower than the current levels, and I am wondering at what point I should increase the KH to stay above a certain pH?

I keep a school of Cardinal Tetras, Otto's and SAE's.

Any advice would be appreciated...

 

Re: How low is low?

Thanks for the feedback Spar.