Precipitate?

[Ippyroy]

My Alk drops 1 Dkh a day. This started about a week ago. I have been having issues getting the DOS to stay primed. I was constantly getting air in the lines for BRS soda ash. I was manually dosing 3 times a day to correct it. I have now set it up with JG fittings and RODI lines. Precipitate has begun to form on the heaters, but not much. My tank has been up and running for about 9 months. The main thing consuming the Alk and Calcium is Coraline, I only have a few Montis and a couple of SPS frags. My sand is beginning to get hard and clump up. I dropped my Alk from 9 to 8 and am trying to maintain it there. It won't stay steady. My calcium stays at 420 and my magnesium is around 1380. My PH is between 8.1 - 8.3. I do not use anything to raise the PH other than the soda ash. How to I get the Alk to stay steady?

 

[Ron Reefman]

I hate to say it, but alk can be steady at any reef tank usable level. It's a matter of getting the alk dose equal to the alk usage. Also keeping the Ca in line with the alk level will help, but it's far less critical.

How much is your alk swinging?

Just so you know, I dose once a week into my 90g DT (110g system). The test level after a week is about 7dKH and I dose it back up to 9.5 dKH manually all in one dump into the sump. The DT is 50% zoas, 25% lps and 25% sps. Some of the sps react by pulling in polyps, but they are back out within a few minutes.

 

[Ippyroy]

It should be around 35ml a day. My calcium stays in check at that amount. My alk stayed in check at that amount for months. Now it falls a full Dkh after dosing that much. Makes no sense.

 

[Randy Holmes-Farley]

1 dKH per day seems pretty normal, and is on the low end for a typical reef tank.