very high nitrate concentration

also I have 6 snails 2 hermits and a red spikey starfish

 

With the gunk on your sand, you can siphon that out on your next water change, it couldn't hurt. And don't feel bad, I think I hold the crown for highest nitrate concentration. Mine was so high that it was completely off the chart, I'm guessing it was in the 200+ppm range. But definitely do a water change, and if you want to get it down fast, try some nitra-zorb in the mean time until you can get it under control naturally.

 

ok so it is like a power filter. A protein skimmer would probably help with the waste. There are many ways to naturally reduce nitrates and i am sure that you could find hundreds of threads about nitrate reduction. I personally like dsb's as long as they are remote and easy to change if you need to. I had problems with reducing nitrates but not to the same capacity as you.(mine were at 25ppm) I tried so many things and then finally the dsb solved the problem. My nitrates are less than 5ppm now and still decreasing.

 

what does dsb stand for? I hear of some stuff called acno3
Is that the same as nitra sorb?

 

a fish only tank can handle up to 60ppm nitrate but with corals i aim for below 10ppm if with the low nitrite levels your filter is obviously doing its job but more frequent more changes are needed,also vacuum the gravel should help

 

dsb deep sand bed

 

Already have a dsb - well at least 2" deep