mag testing

I checked my mag about 3-4 weeks ago and it was at 1500, then I checked it last night and it was at 1200. It is a 240 with a torch, frogspawn, duncans, 2 bta's, a brain, branching bubble,trumpets, some zoas, some mushrooms, and a couple recordeas. I do regular water changes which keeps my cal in check, I slowy drip alk to keep it between 8-9. Any ideas as to what's using it up and is that much loss normal?

 

Do you have alot of Coraline algae??

 

Have you repeated the test or checked the result agaisnt another kit?

 

No I haven't checked it with another kit, it is a new kit but I did check it twice the first time and twice the second time. I did a water change, checked it again, added some mag and checked it about 2 hrs later. It went up a little bit so I added some more and it went up again. I'm only adding enough to go up 10 ppm each time. I don't see much coraline but maybe it is starting to grow.

 

What kit do you use?

 

Salifert