Phosphate problems and potential consequences?

[robbyville]

Thanks as always for the swift replies!

I'll start by answering the questions:

I use RO/DI water, measured with a TDS meter at 1ppm

Tank is 60 gal. Filtration is through rock and sand with the only mechanical media being what I put into the prism basket, and a couple of sponge blocks in the overflow. Come to think of it, I have not washed those sponge blocks in months!

I change the media in the prism basket about once per week and alternate between carbon, and nitrate sponge (now including phosphate sponge).

I perform a water change every 2-3 weeks of aproximately 5 gallons.

I started out with a 3 inch sand bed, but I have a sand sifting goby, so there is no real way for me to say that this bed is acting as a DSB.

The tank has a small sump/fuge built into the back, as such I have an area of about 1 foot long by about 3.5 inches wide that also has a 5 inch DSB in it. I'm not sure though how much good this actually does.

I feed once per day, small combination of mysis or brine, mixed with flake, and pellet. Bio-load is 7 small fish, and a variety of small corals. You can view my gallery to get a sense of what's in the tank as well. I have recently started to add a squirt of bio-planktone once a week or so. I also every now and again use a little coral-vite.

I think that answers pretty much all the questions, thoughts?

Rob