I posted about 3 months ago as my Phosphate level was rising and Howard kindly suggested a Rowaphos reactor which is now in place happily removing Phosphate :) My level is now 0.03.
I now have a problem with Nitrates... I have caleurpa in my sump with the skimmer skimming nicely but the Nitrate level stays between 25 and 50. I am changing 10% water weekly, cleaning skimmer cup and replacing filter floss twice a week without any reduction.
Im sure it would help but its quite expensive. have you tried all other options first? like increasing flow rate round your live rock etc? are you using bioballs or anything like that? they can cause high nitrates. whats your feeding regime? stock level?
Thanks for your response. One of my powerheads in the display tank has been playing up lately so I have just replaced it with a Koralia which seems to have a nice wide flow. Will this make much of a difference?
The tank is 220l plus 50l sump with the following stock: regal tang, firefish, royal gramma, coral beauty, dwarf angel, fire shrimp x 1, 11 crabs and 4 turbo snails.
I feed a pinch of flake once a day and a pinch of granules later once per day. I feed a 1/2 block of frozen every 3 days.
Firstly, have you tested your RO water directly as it comes out of the unit and before you catch it in your container, then test again when it has stood for a while in your collection container, then test again after adding and mixing in your salt to rule out any issues with that? If you get pre-mixed from LFS test that instead. If theres no issues with your freshly mixed water it could be that you are overfeeding or overstocked (I'm not familiar with your stock level or tank size). Do you rinse your frozen food in RO water before feeding? it can be very high in nitrates and phosphates if you don't. Have you tried another liquid test kit and got an equally high result? It's best to rule everything out before going to the expence of a nitrate reactor.
In adition to what freakyshrimp suggests, it could also be a test kit issue. Hobby Nitrate test kits that are available to the likes of you and me are not all that good and have quite a short shelf life. Certain brands have reportedly been giving false high results. I think perhaps take a good critical look around the tank and see if you have any symptoms associated with high nitrates. Rampant algae, listless fish or poor appetite, corals dieing?
If you're not actually getting any problems then you can relax a little and perhaps try another brand of test kit first - your lfs or another local fish keeper should be able to offer a nitrate test on your tank water for comparison. You can also try www.tanktests.co.uk to get a benchmark test. These are reportedly very accurate.
i dont think your hermit crabs will help with the algae and there quite destructive in large numbers. i would recommend reducing the number of them alitle. i always follow the rule of 1 hermit crab to 10 gallons. will reduce the load on your natural filter too so certainly wont make your nitrate problem worse.