[Myka]

Sorry I forgot to revisit this thread when the notifications were down. I'm also not able to see all the "New Posts" either. Annoying, but I digress...

Could you post a pic of your tank so I have an idea of your rock work? I'm thinking you could probably use removing some rock. The reason why you're struggling so bad is because the nitrate and phosphate get absorbed into the rock and sand beds, and as you change the water more leeches out. This is why I suggested biopellets.

One of my clients' tanks when I first start with the tank was around 750 ppm NO3 and 2.5 ppm PO4. The tank is now just under 100 ppm and 0.25 ppm respectively. This is from using biopellets. The system is about 250 gallons and is in a high rise office building, so there isn't much space. I can only do 20 gallon water changes. I started off by removing the rocks, scrubbing them down to remove detritus and massive amounts of hair algae, cyano, and even dinoflagellates. I did half the tank one week, and half the tank the other week. I vacuumed the sand too (~3"). I cleaned the skimmer up and the sump. Weekly maintenance included pulling out clumps of hair algae, sand vacuuming, filter pad change, and then it was just a waiting game. I didn't do anything special, and I didn't do ANY big water changes. My point is, biopellets work very well in these sorts of situations.

If you choose to use biopellets, there are a few things that I've found make a big difference. Choose a recirculating reactor so that you can control the effluent to just a trickle (too fast and the biopellets are too aggressive). Place the effluent hose so that it goes into the skimmer. Start off with 1/3 the amount of biopellets the instructions say to use, and don't add more until 4-5 weeks in as it takes about 3-4 weeks for new biopellets to start working.