I have always had high Mg levels in my tank and would like some feedback from other Aquaforest users about their experience. I have a 20 month old 65g tank (RSR 250) and use the Aquaforest Reef Salt and Component 1+2+3+ dosed daily via DOS units. I have used this salt from day 1. I change ~15% of water every 4 weeks, and just recently have changed this to 15% every 6 weeks. I have been dosing since the tank was about 1 month old, initially very small amounts, increasing as the demands grew. The tank is a mixed reef with 6 small/medium fish, sand sifter starfish, hermit, coral banded shrimp, CUC of ~8 snails. Coral load is light-medium - 2 Acros, large Sinularia, Trachy, Cynarina, Goni, reasonable sized Zoanthid colony (mix of small and large), Favia, Hammer, Torch, Mushrooms. My currently parameters, as tested today, are Kh 8.4, Ca 430 ppm and Mg 1560 ppm. Mg has always been high - the first times I tested in Oct 17 levels were ~1440 ppm. By Dec 17 Mg hit 1600 ppm and has pretty much stayed there ever since. My test kits are Red Sea Pro. A couple of months ago I bought refills so I took the opportunity to test Mg with both the old and new kits, and the results were identical, so my test kits appear accurate. I test weekly and the parameters have been stable at this for months now. I am currently dosing 22 ml/day of Ca and Mg and 24 Ml/day of Alk. I stopped dosing Mg for a few months trying to bring it down but that didn’t affect it, so I have started dosing Mg in line with Ca as recommended. I am currently watching to see if Mg drops over time due to WCs. What Mg levels do other AF users test at? My tank is doing well and after struggling with GHA issues for 9 months has been in a really good state for 3 months now, so the high Mg doesn’t appear to be causing any issues.