Pet Forum / Aquaria / General / October 2004

The nitrate level in the tap water that I use is also 0ppm, but the nitrate levels in my aquarium never get any higher than 4ppm, which I think is slightly lower than what my plants need. I put it down to weekly 25% water changes and a two weekly gravel clean. my aquariums also planted, which also lowers the nitrate level.
 I have  just got a Nitrate Testing Kit and tested the water and it is 40-80 which is high, what do I do to lower it and stop it happening ? I am still new to this all and would like some advice from you all experienced people. We did a control sample of the water we use for water changes and that was 0.

 Mary

new to this all and would >like some advice from you all experienced people.
We did a control sample of the water we use for water changes and that was
0.

Nitrate is the final stage of the nitrogen cycle. Unless you have a means of
denitrifying your water within the filter system, you have to dilute the
nitrate out. If you are using tap water, you will find that the levels are
anywhere between 10- 40ppm, therefore removing 80ppm water and replacing
with 40ppm water will reduce the overall levels only slightly.

Two ideas may be that you have too much bioload in your tank (i.e. too many
fish) or that you are overfeeding them and the food rotting is contributing
to the high nitrate level. Consider reducing your feeding, or even cutting
it out for a few days whilst carrying out a 20% change every day to see if
that brings the level down.

If you have a canister filter, you may want to consider some sort of ceramic
media like siporax biohome, or alfagrog. These media have a high surface
area and allow a small amount of denitrification to take place. I had a 6
foot tank with two canisters, one canister filled with a sponge and the
other 2 baskets with biohome, the nitrate level never registered on my kits.

Plants will take up a small amount of nitrate but don't rely on them too
heavily. There was an article in PFK a couple of years ago which suggests
that plants actually prefer to feed off ammonia, but will settle for nitrate
if they have to.

Hope this helps a little.

Mark