Originally Posted by mynd

@Pnoy, An ALK of 8 is not good. You need to raise it to a number between 10 and 12. Alkalinity is created by carbonate and borate alkalinity. Borate alkalinity comprises about 2.8 DKH of total DKH at any given time. If you have a total DKH of 8, that means your carbonate ALK is 5.2 and is way too low. You want to get your total ALK up to about a 12 so that your Carbonate ALK is about a 10 or a 3.3 meql.

That would mean that you need your tank to have a 4.3 meql ( depending on your kit ) at all times or a 12 DKH.

DKH test kits test for total ALK and do not consider borate alk, which is not contributing to Carbonate ALK ( which is needed to skeletal growth and coralline growth in your tank.

I suggest using a seachem reefstatus magnesium test kit ( which includes alk ) as it gives you the best ( IMO ) understanding of alk levels in your tank.