Phosphate getting out of control

[Gem Tang 88]

I took over a tank a few months ago, the RO/DI unit and phosphate test kit were also handed over to me but i didn't realise they weren't working properly. Tank has a shallow sandbed and i've siphoned it 5 times. Put in a bio pellets reactor 4 weeks ago and nitrate has gone down to almost undetectable. Phosphate was at 10ppm and after 75% water change and phosguard was put into place, phos has gone down to 4ppm and i'm having trouble to bring it down further. What should i do now ? I have 2 tangs and a chromis, i fed them very little amount, the blue tang gotten so thin, i really need help

Nitrate 0
Ammonia 0
Nitrite 0
Phos 4
Akalinity 9dKh
Cal 460
8.2 Ph

[j.a.c.wester]

Best think you can do is buy a big bucket of rowaphos and i mean realy big. Fill a reactor till the maximum amout of rowphos. Any type of fosfate remover is only capable of removing so much.

example.

1000grams/ml rowaphos os capable of removing 3 grams of fosfate out of 4000L. If the fosfate in the tank is 12 than your 1000grams of rowa is only good for a tank of 1000L. But do to thw fact that fosfate binds itself to rock the rock will give the phos back to the water thus raising the p04 aqain. Therefor buy a big bucket and hammer the phosphare down with what lookslike a lot but in the end the biggest chance is that the medium cant keep up with you rock.

I dit this a couple of times with other tanks and wprked like a charm. Dont worry about the sudden drop in po4. The same thing happens to your thank when you do a 70% waterchange.