alk at 4.3?

I just setup my reef for a month now and just this weekend I got a killer deal on some frags. 3 zoa frags, a 3" birdnest, but most notably a monti colony about 10"x8" with several layers forming.

the day before the frags, I measured a alk of 8dkh. The next day I measured an alk of 6. So I decided to mix some BRS soda ash and dose according to instructons. Today after 10hrs of the last dose of alk I measured a staggering low 4.3dkh. Done with a salifert test.
I also use kalk in ato.

my question.is can it even get that low? And in this short a time frame?

 

Also all the corals look good, extended polyps. No stress that I can see with the eye.

 

What size tank, and what are your cal and mag levels?

 

40b w/ 20l sump. Calcium is at 400. I don't have a mag test, something I will need to get.

 

My guess is that your mag is low.

 

Ok, I will have to make a trip to the store for a kit.

 

is your test kit still good? if your sps is fine i don't think that drop in alk is right. going from 8 - 4.3 in two days is pretty drastic change.

 

I hope so, I checked it twice cause I couldn't believe it. I think a few lfs in the area are willing to test my water too so I'll have to get a sample and tested by someone else.

I have never heard of alk at that range myself.

 

Agreed! I would stop dosing until you confirm your test kit is accurate. You should definitely get a Mag test as well as already mentioned.