[Ron Reefman]

Ok so I've been reading lots of threads and tested today since my acros where not to happy . Alk is 9 dkh
Cal. Is 425
But my mag is the problem. Thought it was 1500 but as I'm typing this the color keeps changing so I keep adding more Titrant . And I'm past 1600 .
My question is how do I drop mag slowly


First you should probably try to find just how high your Mg is.

High Mg isn't a serious issue even up to about 2000. I'm unsure beyond that. You can just let it come down naturally but unless you have a LOT of sps and lps corals it will take a long time (months?). Water changes will lower the Mg level. Just do more frequent smaller changes and the reduction will be slow, although rapid changes in Mg are a serious issue IMHO.