confusing water levels

[fishfun]

I am fairly new at keeping cichlids. I have a 30 gal tank, aliitle over stocked, but some fish are being moved. After my tank was cycled my ph was 8.2, Amonia 0 Nitrite 0 and Nitrate 40. I started doing water changes 2-3 times a week to bring the Nitrates down. I then bought a better nitrate test ( I was using dip sticks) and when I tested my water the nitrates read 15ppm. The package said dip sticks gave higher readings than actual. My current os Amonia 0, Nitrite 0 and nitrate 15. Is my nitrate too low from all the water changes? What should be the consistent number, so I know my water changes are appropriate?

Karen

 

[Slappy*McFish]

at 15, your nitrates are just fine for cichlids...anything under 30 should be fine in the long run...40 is pushing it.

 

[JSchmidt]

Keeping a fully stocked cichlid tank under 40 ppm nitrates is doing pretty good, in my book.

I've never found the dip sticks to be that much higher than other test kits. They are a bit less precise, but usually not that much (unless they're past their expiration date).

Also note that there are two different scales used to represent nitrate. Using the more common measure (on the boards, anyway), keeping your tank under 40 ppm is doing great. The test of this sort that I've seen present it as "Nitrate". The other measure, usually presented as nitrate-nitrogen" is one-tenth of that figure; for these tests, you want to keep nitrate below 4 ppm.

Since nitrate itself is not necessarily that toxic, except at higher levels for long periods of time, we usually use nitrate as a general measure of the buildup of metabolites and other pollutants in our tanks. Knowing the nitrate level of your tapwater can help you guage how frequently you need to do water changes.

Good luck,
Jim

 

[RTR]

Errr, ummm - the conversion factor from nitrate-nitrogen to nitrate is 4.4, not 10. So 40ppm nitrate = ~9 ppm nitrate-nitrogen (or 9.1, but it is not significant). Or in the other direction, 10ppm nitrate-nitrogen is 44ppm nitrate.

The conversion factor from nitrite-nitrogen to nitrite is 3.3. So a reading of 0.25ppm nitrite-nitrogen = ~0.82ppm nitrite. Or the other way, 1.0ppm nitrite = ~0.3ppm nitrite-nitrogen.

These conversions represent the portion of the ion that is actually nitnogen. If you are doing nitrogen balances at various stages of the process, it is far more obvious to track the nitrogen only, not the oxygen or hydrogen or whatever is combined with nitrogen at a particular step..

HTH