A Water Mixing Question...

StuartGA1

Member
I have a RO/DI system for making my water. When I mix I usually mix the salt in until the salinity is 1.026 and then check and adjust the ph to about 8.3. My question is: considering that adjusting ph can effect alkalinity, would it be better to adjust the ph first, then mix the salt and check the ph?
 

lmforbis

Well-Known Member
Because RO water has no buffer capacity you won't be able to adjust the pH first.
Why do you need to adjust the pH? The salt mix should have the buffers already in it to maintain a stable pH.
In the 15 years I have kept a salt water tank, I have never adjusted the pH of my freshly mixed salt water, old water either for that matter.
 

StuartGA1

Member
Generally my ph is below 8.3 after I have mixed it. So I bring it up to that. I use the water for both a reef tank and a FOWLR tank.
 

lmforbis

Well-Known Member
How far below 8.3? How are you measuring the pH? A pH of about 8 to about 8.4 is good for salt water. You shouldn't need to adjust it up in freshly made salt water unless it is really low which shouldn't happen in quality salt mixes. pH also changes depending on aeration and whether the lights are on or off as well as other parameters in the tank.
 

StuartGA1

Member
Well, I am talking about my change water. It is in a 30 gallon, covered container. I keep a power head in it all the time. I use Ocean Reef Crystals and check it after I get it to 1.026. My ph at that point is usually showing 8 or a little under.
 

lmforbis

Well-Known Member
I believe pH tends to go down in the dark. For that reason a lot of people run their refugium lights in an opposite cycle to their tank lights.
 
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