Magnesium

[Vansaquaescape]

So I have been testing my water Everyday and my parameters are
420 Calcium
8.5 to 9.3 Kh
1200 Magnesium
Started adding Kent’s magnesium for 3 days and can not get it to Raise. Any Advice ? Would be much appreciated have a Kung Pow Monti on the way and would like it to be around 1300. Also when mixing saltwater batches How long should I wait before using the saltwater ?

 

[Vansaquaescape]

So I came home and just went ahead and dumped more magnesium into the tank. Tested it before I put magnesium in there and it was 1260 so it had gone up 60 ppm. When ahead and added the rest of that magnesium and it bumped it up to 1320. Wondering what salt people recommend so that I can maintain a magnesium of 1300.Thanks