0.4 pH swing...bad?

[Son Of Skyline]

Thanks for the tip Tim. I'll do that. Hopefully a good sized airstone will do the trick.

Originally Posted by TimT

I would think the kalk is binding up the CO2 at night and then during the day photosynthesis further depletes the CO2 thus causing an even higher pH. I would recommend increasing the gas exchange in your tank. If your pH goes much higher than 8.55 - 8.6 you will start to lose corals.

Cheers,
Tim