Magnesium levels LOW need some advice.

loki6969 · Oct 24, 2017

Here is the deal I left for 6 months on a business trip came back and my Mag was 760 and I have red fuzzy algae when I left everything was spot on so I have bought the 2 Part Magnesium Mix Aquarium Supplement from BRS and have dose almost a full gallon in the reef and both test kits are showing 800 it only cam e up 40 PPM. Is this correct will I have to dose 4 gallons to bring up the levels .

Tank 220
Sump 40
CA 460
ALK 9.5
Mag 800
N03 0.0
N02 0.0
P04 0.2
Salt 1.026

Randy Holmes-Farley · Oct 24, 2017

It is almost certainly test error.

What was added to the tank in those 6 months?

loki6969 · Oct 24, 2017

Just a couple of water changes and my CA reactor was running.

Randy Holmes-Farley · Oct 24, 2017

Real depletion even when no magnesium is added might be 1-2 ppm per day.

Before assuming the value is that low, verify it it some way, such as by testing new salt water with the same kit (and getting much higher values) or using a different kit to check it (such as at a store or a friend's).

loki6969 · Oct 24, 2017

I will do that when I get home. I thought something was wrong when I get back and the tank had red fuzzy algae all over the rocks I just figured it was PO4.

loki6969 · Oct 24, 2017

I feel so stupid because the 2 test kits I have been using is a Red Sea and it seems to be the opposite of every test kit I have ever used. This kit says to measure not the titration that is left but what has been used so once I saw that I did some calculations and the Mag is 1400.