Wait so NSW is ok for tanks? It’s good even?I would use NSW if I could get it. Lucky!
The cause of algae is a bit complicated and not even always tied to nutrients. There are many higher nutrient tanks without algae issues.
I believe battlecorals runs higher salinity and he is a vender of acropora. At least he did in 2018.. I guess I have no idea now You can just add some RODI or distilled to what you are buying and bring it down.