Diatom's are feeding off the Silicates. Should clear up on it's own. Nerite snails will make short work of it. I just put 10 nerites in my new set up that is going through a diatom bloom and they basicly had it gone in 5 days. I also put a GFO Reactor on line also. It will pass. As for aragonite may i suggest Carib Sea Special Grade Reef Sand.
Keep doing weekly water changes with 0 tds ro/di water and you will help solve your problem. Using tap water may have helped contribute to your problem.