Yeah, I really blasted it with my garden hose outside. I only had a small quantity to make it easier. I took my time and only stopped once the water was coming out crystal clear. I didn’t rinse in DI because there are no phosphates in my tap water.Did you rinse the sand in tap water then DI? When I say rinse, I mean did you blast all the crud out?, completely?
Mbunas are really messy fish. And aggressive. You need to have an overstocked tank so they don’t kill each other. So I’m not surprised the sand is still showing 0.5 ppm phosphates after a thorough rinsing.
Oh, and this sand is only 6-8 months old.