pH - Safe Rate to lower it

[TW]

Had a mishap with my pH controller electrode, which meant haven't been able to put C02 into the tank. I have my new electrode now, but while I was without it, the pH went up to 7.18 & I'd like to take it back down to low 6 or even under.

So I do this gradually, what would be a safe daily pH target to set on the controller? I've set it at 7.0pH & thought tomorrow, I'd set it at 6.9pH. Is this too conservative, or not conservative enough? How fast can I take it down while still be kind to my discus & apistos? Don't want to shock them again - that would have already happened to them when the pH shot up with the end of the C02.

Thanks for any advice.

[Bad Inferno]

On a water change my pH goes up to 6.6-6.8 then the CO2 brings it back down to 6.5 within say 2 hours. No effect on the fish at all. Just move it 0.2 ph per day

[ILLUSN]

I drop mine by about 0.5 a day with water changes, my fish seem happy enough, a few times its even triggered a spawn.

[TW]

Thanks Bad Inferno & ILLUSN

[Hollowman]

Changing Ph should be done slowly to be safe, fish can suffer what is called Ph Shock or Osmotic shock. This is when the fish cannot balance their internal fluids to the surroundings and they end up dead if you are not careful. The differencce between each Ph number is multiplied by a factor of 10, so this means there is a big difference in internal balance.
Reducing the Ph as mentioned by .2/day should be safe though.

H