high no3,no po4

bobt2

Active member
i,m still fighting a 50ppm nitrate issue in a 5 week old tank.loads of live rock and sand from fl and no fish yet. i run a gfo reactor with 0 po4 showing. i was told the 0 po4 is why my no3 will not come down? why?
 
Running GFO in a newly set up tank from the start is not ideal in my opinion (if you have sky high phosphate due to the rocks used that's a different story). As you have noticed bacteria etc. will need at least some PO4 to function. If you have zero algae growth that might well be the problem. I would disconnect the GFO reactor and see if the situation improves with normal feeding of the tank.
 
Disconnect the reactor and observe the situation for a few days - maybe the situation will improve. Otherwise I'd feed some food high in phosphates (most processed food and things like Cyclop-eeze should work). You could also add phosphate as an additive - there are threads in the advanced questions forum that talk about the issue.
 
Some organisms will help export nitrate by consuming it from the water column. Algae and some bacteria can do this, but they require phosphate to grow. So a tank low in phosphate could in theory do better with a bit more phosphate in the water column.

Personally, I'd measure the nitrite level first. Small amount of nitrite will confuse a nitrate test kit. I'd get a second opinion on the nitrate test kit, too, since they can fail. The kit should zero on distilled water, which can be a useful sanity test.

I would avoid making any changes until I had the testing issues resolved.
 
ok, nitrite is zero. both salifert and api kits are showing the high nitrates, api more so than salifert.
 
When either NO3 or PO4 is excessively out of balance, you may experience the other remaining high for a long time, which is what you are seeing now. I would recommend that you take your GFO reactor offline for a while and get your PO4 levels up to around 0.03-0.05ppm. In simple terms, you want more bacteria growth in your water column in order for that the increased bacteria count can consume the excess NO3. Bacteria need both NO3 and PO4 and if PO4 is low, then the PO4 becomes your limiting factor to getting the bacteria count up so that the nitrates can be driven down naturally. I keep a bottle of liquid phosphate around just for this purpose. It s called NeoPhos but there are plenty of others out there for Ultra Low Nutrient Systems. I don't need to use it often but when NO3 rises above 10ppm, I add a little PO4 and the NO3 drops like a rock every time.

A carbon source is also important and fish food, vinegar, bio-pellets (etc) address that need. If you are just cycling an empty tank, taking the GFO offline and adding a little fish food is basically all that you need. You may want to read up on vinegar dosing as it can help speed up the process too, although nothing good happens fast in this hobby! Best of luck to you as I'm sure your will have success.
 
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