Nitrate issue?

Ok, So i've been having this weird issue with my Nitrates and frankly I just don't get it.

For about three to four weeks my nitrates have been 20...and they haven't changed at all, even though I've done everything I know to do to fix the problem. Here is what I have been doing..

- Removed bio wheel
- I have double carbon filters, and usually only replace one and leave one in to hold bacteria; changed them both over the two week period.
- Done two water changes (as normal tank maintenance would require, i do these bi monthly anyway), by vacuuming sand. I guess it would be about a 10% water change.

So what should I do? Since they aren't getting worse does that mean I fixed the problem and I just need to do a bigger water change?

How high do Nitrates have to be to be harmful to tank inhabitants?

Let me know if you need to know anything else

P.S. been monitoring ammonia since removing the bio wheel, all is well

ammonia: 0 ppm
nitrite: 0 ppm
nitrate: 20 ppm
pH: about 8.1-8.2
sp gr.: 1.022

temp: between 75-77 degrees

 

Somebody please correct me if I am wrong, but 10 percent of 20 ppm is only about 2ppm (leaving a total of about 18ppm nitrates in your tank). This water change regime probably wouldn't significantly decrease the nitrates. If you want better nitrate reduction a fifty percent water change would reduce your nitrates by about half. I am not recommending that you do an instant 50 percent water change (due to stress on your livestock), but I think that larger water changes are what you need to decrease the nitrates. 10 percent a month doesn't seem like enough to me (for a nitrate reduction). I do 10-15 percent a week, and my nitrates stay between 5 and 10 ppm. Just my thoughts..

 

If they are not rising you probably have it in check. Think about it this way. 20ppm if we just say thats equal to your gallon at 20 gal. When you change out 10% of your water at most you'll drop it 2ppm to 18ppm. This probably wont even register on your test. It will take time to get them down, just like everyhthing we do! Nothing happens quickly.

 

You type faster then me!

BTW don't ignore the 20 ppm but don't panick either it can be double that with little affect, but you are taking measures now.