nitrate levels in freshwater tank

Question
Hi Karen, I have a 35 gallon tank which has high nitrate levels (160ppm+). pH is 6.6, ammonia and nitrite are both 0. I have been carrying out 10-20% water changes every week for the past 4 weeks and adding a waste control product as advised by my local aquarium dealer, but this has made no difference to the nitrate levels. I have checked the nitrate levels in my tap water prior to treatment as I understand that this may contribute to the nitrate levels. The nitrate in the tap water is 40ppm (mg/l). I am loosing fish and want to know if there is anything i can do to reduce the nitrates? Many thanks in anticipation!

Answer
Hi Diane,
I would increase the amount of water removed to about 1/3-1/2 of the tank water at least 2-3 times per week. You could try using Amquel Plus or Prime water conditioner since it helps remove nitrates as well as ammonia, nitrites, chlorine an chloramine. Make sure you are siphoning your gravel regulary and cleaning your filters in aquarium water. Also, don't overfeed since this can also contibute to your problem.  If you are possibly overstocked in your tank think about getting a larger tank. All of these factors can contribute to raising the nitrate levels and especially since you already have a higher amount in your tap water. Be careful about adding too many chemicals to  your aquarium other than the water conditioner I mentioned. Sometimes adding too many chemicals to try to control water conditions can create  more problems. Most things can be controled by regular and frequent water changes or even by just removing more water to help control the fish waste.
Hope this helps,
Karen