I agree it is probably testing error. The magnesium change seems to oddly mirror the calcium change, but in reverse. Unless you add one or the other, that cannot happen.
Randy,
Sorry to Hijack this thread but I see you are the one to talk to regarding Alk/Kh levels being low.
I recently set up my tank, it is currently ending its cycle and all parameters are looking good apart from the KH which has dropped from 9 to 6.5 in a matter of weeks, I was only really conentrating on ammonia, Nitrite nad Nitrate until this opint so do not know how quickly it has dropped?
I have a PH of 8.1 which seems to be the same since I started the tank so I used the calculator you suggest and on my 140l tank to raise it from 6.5 - 9 again using your part 1 it says;
66 ml; 2.2 fl oz; 13.2 tsp
would I just put in a small amount every few hours or twice a day? And would i then need to switch to the part 2 for stability or just maintain part 1 with dosing when test show a drop? as long as the PH stays the same?
I only have 2 cleaner shrimp, 2 small clowns, 3 small hermit crabs and 3 zombie snails in there along with a couple of kilo of live rock so god only knows what has caused it to drop? I will be looking to keep soft coral and the LPS at some point so will get a dosing unit but didnt think I would need all of that with a handful of fish?
Sorry for all the questions, it is appreciated that you are here to help the likes of me though, thank you.
Lee