DKH issues
 

I seem to be having big issues keeping my dkh up. I have been adding buffer for the last 5 days and it goes in between 6.7 and 7.4.

I don't get it. Calcium is okay and my test kits are salifert and new so its not that. I know that running phosphate remover has an effect but i should be able to get it up and keep it up with a buffer.

Suggestions would be great.

Craig

How is your magnesium? that will affect the cal/alk balance

What salt?

I use IO and had the exact same problem as you about 5 years ago.

Now I add enough magnesium to get my levels to about 1380ppm and I have no problems at all keeping my alk at 9 or 10.

Before the best I could get was 7 or 8 and I had NO CORALS! I would add some buffer, but no real change. Eventually I noticed that it was all precipitating on my pumps and heaters.

I had the same issue, and tracked it back to my salt brand. My prefered salt brand has low dKH naturally. I now just use a calcium reactor to maintain my alkalinity.

Firstly, check your Mg as others have suggested.

Secondly, I recall reading a Holmes-Farley article a while ago indicating that:

1. Alkalinity naturally fluctuates far more than Ca levels, so there's no need to panic when you see Alk drop but Ca remaining stable.

2. If you still see Alk dropping, add BOTH Alk + Ca in equal parts. Since the two are so closely interrelated dosing one independently of the other (the standard reaction) is almost always bound to lead to frustration. Do this with either a balanced 2-part additive or a Ca reactor.

Magnesium seems to be the problem. Which is odd as i checked it not that long ago and it has always been fine.

Thanks though for all the comments got me thinking the right way:)