Alk not rising

[Reef.Blue]

I have been having some alk problems as it has been a little low around 7.1 DKH. I purchased the red sea alk supplement and measured out the correct amount to raise it to 8.5, but it only went up to 7.3 the next day, so I am a bit confused on what is happening. Anyone have any ideas?

 

[Formulator]

I have been having some alk problems as it has been a little low around 7.1 DKH. I purchased the red sea alk supplement and measured out the correct amount to raise it to 8.5, but it only went up to 7.3 the next day, so I am a bit confused on what is happening. Anyone have any ideas?

First of all, I’m glad your alk did not increase from 7.1 to 8.5 overnight!! That is a great way to kill your corals! Never raise Alk more than 0.5 dKH per day.

Now that’s out of the way, there are several possibilities as to why the Alk did not go up. The most likely is probably just a calculation error. What is your supplement exactly and how much did you put in? What size tank? With that info I can double check the math for you. Another possibility is precipitation of calcium carbonate. How old is the tank? How did you add the supplement (i.e. poured into sump, powerhead, etc)?