Help! Alkalinity at 12.9

[Darryn Lyon]

I miscalculated my last dosing of reef buffer and jacked my alkalinity to over 12, then added in some coralUp a few days later without realizing it has pH support in it, and now it's sitting at almost 13. I have some coral that are dying, presumably from the alkalinity. My hammer coral is toast it looks like, and some of my zoas don't look so hot. I don't know what else it could be. Can I add something to lower the alk? I dosed some magnesium last night to see if that might help strip it a little bit. I'm about to do a water change today, about 10 gallons (I have a 32 gal. Biocube.) Can there be something else going on in the tank that can jack alk up that high?

Alk 12.9
Mag about 1440
Cal 430
Nitrates about 15
SpG 1.0265

 

[nemo1017]

Do a water change and let it fall back down gradually. Another sharp change in alk will streSs the coral more. Small increments are best.

 

[skim]

You could also just leave it and it will fall on its own. If nothing is stressed I would leave it.

 

[Randy Holmes-Farley Verified Community Expert]

I don't think corals are dying from the alkalinity. Many tanks are kept at higher alk and corals grow well (faster than at lower alk in many cases).

Salt mixes can have that much alk in them, and if you have low demand it may just reflect the salt mix.

 

[DaveMorris]

So here is a loaded question...what should we be targeting our alk to be? I am looking at a tank with some LPS and SPS mixed, but heavier on the SPS.

 

[Randy Holmes-Farley Verified Community Expert]

So here is a loaded question...what should we be targeting our alk to be? I am looking at a tank with some LPS and SPS mixed, but heavier on the SPS.

I recommend 7-11 dKH. Lower end of that for a ULNS tank, higher end if you want faster growth of hard corals.