1600+ magnesium

[Vet reef]

I've been running my tank a magnesium levels over 1600 for 2+ months. I over dosed once and I've been trying to get it down ever since. Corals are fine, but I think I can get more growth out of my sticks if the magnesium was a couple hundred points lower. anyone have any tips to get it out of the system? Been doing weekly water changes and have seen no difference

My tank is sitting at
Temp 77
Alk 10.5
Mag 1585
Refractor 1.0255
Cal 432
Ph 8.28. Trident shows normal. Dripping kalk 1 drip every 3 seconds.