I have phosphate issues in my 55 reef. The color of my corals was mostly browned. I have been battling it with GFO
through a reactor, but didn't see much improvement. I added a Hanna checker, Hanna Checker Phosphate PO4 Colorimeter - Bulk Reef Supply
, and it has greatly assisted me adjust things. The hair algae growth has slowed considerably. It can take months for corals to regain color, so I can't report on all of them but many are getting bright.
Sometimes things can be expensive in the SW
side of the hobby. The tester costs 50 bucks, might not be in everyone's budget but it is the best phosphate test for us as hobbiests IMO
. It is simple to use. If you are looking into these, I would assume that you are getting into corals. If this is the case, the Hanna calcium, alk
, and phosphate tests are bundled together on marinedepot.com for less money and might be worth looking into for a "down the road" sort of purchase.