[Milad]

Originally Posted by PoonTang

did you calibrate your probe using both ph7 and 10 solutions?
are you running a ca reactor?
what is your Alk at?

Originally Posted by Megalodon

If your kH and calcium balance is OK, I wouldn't worry as much about pH, as it really comes down to CO2 at that point. CO2 levels go up at night and thus the pH falls. I also noticed the deeper I place the pH probe, the lower the pH is, so keep that in mind.

As for using that buffer, it's not the best idea to use it until you know your alk and calcium levels. To a lesser extent also magnesium.

Since you're putting the calcium reactor on hold, instead of that pH buffer, I would actually recommend to you a two-part. Kent makes a decent one IMO. There's part A and part B, both in liquid forms, added to different parts of the tank, or at different times, always in equal amounts. You could also consider dripping lime at night.

http://www.jlaquatics.com/product/k-...+-+64+oz..html

ill go return the ph buffer and try this two part and see what happens.