My mg depletion rate is 100ppm. Is it possible?

[The Grizz]

Originally Posted by Coleus

I have no sand bed and this is not a new tank. It used to be FOWLR tank and then switch to reef tank.

I top up about 15 gallon of RO FW per week and do 15 gallon of water change every week

I have stopped topping up with FW and only use SW it has helped to keep my levels up. I keep my salinity at about 1.025 but top up with water with a salinity at 1.022. I found when I did use FW my levels dropped and it was hard to get them back.