PH help

I just installed my bulk reef supply RO/DI unit and everything is going great water is crystal clear my nitrate, nitrite, and ammonium are all zero. The only problem I am having now is that after I top off my tank it takes my ph from 8.4 to 7.4? Ive been having to add ph buffer each time I top off...I know this change in ph has to be super stressful on everything in the tank...any suggestions? THANKS!

 

If you could post magnesium and alk vaules that would help to narrow it down.

 

The test kit I have doesn’t include those...it happens each time I top off??

 

Stable magnesium and alk values will help to maintain the pH. Adding any buffer to a system without testing the alk levels is risky. I would either purchase a new test kit that includes those or have the LFS test until you aquire them.

 

Corailline gave me the same advice a few weeks ago and the magnesium was the culprit for me. I used Reef Crystals salt mix and the calcium levels were perfect but the magnesium was only 1100. Bringing up my magnesium slowly brought up my alkalinity and my pH has been stable.

 

When you do you top offs do them more often than one big one. Your salinity goes up as the water evaporates and then you bomb it down when making a large top off. pH of top off water is 7.0 so you are going to drop your pH with a large top off. Definitely get a Mg kit and then get your parameter up to 1350ppm at least.

 

Will do and thanks I think I'm going to pick this up
Reef Master Test Kit
and whats a good brand for a Mg tet kit

 

Salifert, would be a good choice IMO

Steve