Pet Forum / Aquaria / General / September 2004

Nitrates in the tap water you used for the water change? Try testing your
tap water. I find the levels in my tap water go up at this time of year
quite a lot.

Otherwise Nitrates will build up as an end product of the cycle anyway -
Ammonia - Nitrite - Nitrate.

Keeping them down can be achieved by heavy planting, low stock levels &
light feeding (of fish!).

If you can't keep them in check that way then you can look at:

a) Something like a Nitragon tap water filter (about £45-£50). This is
rechargeable (with salt water) and will strip all the nitrates out the water
you use for changes. I have one of these and it works well - then again I
need about 30-40 gallons of water a week for my water changes.

b) If your tank is smaller (say 30G or less) then you could look at using
something like Nitrazorb in your filter. Works in the same way as the
Nitragon (ion exchange) & again needs recharging with salt water. Ideally
you'd need too packs - one in the filter & one being recharged/ready to go
back when the current one is exhausted

c) You could try & build (or buy) a Nitrate filter. These are a bit finicky
but, once going do work viciously well. The downside I found is that they
also do strip the Kh buffer out the water which, if left unchecked, will
cause a Ph crash. You can restore the buffer by either having some marble
chips in the filter or by adding Baking Soda to the tank periodically. You
can buy a Ratz sulphur based Nitrate filter for about £45 & then you'll need
to find a way to drive it (i.e. a pump or some valves or tubing to "T" off
an existing external filter/pump)

Those are the only ways to control Nitrates I know of and I wouldn't say any
of them constitutes "adding chemicals" - whether they are relevant to you
kind of depends on the scale of the problem & how much water you need to
work with. For a smaller tank the Nitrazorb is probably the best option, for
larger tanks/systems then  a Nitragon & if you have  heavy stocking then you
*might* consider a Nitrate filter but its a bit of a faff(!)

HTH

I.

Even with 0 nitrates in the tap water, I usually only aim to keep ours
below about 50ppm and everything is healthy, stable and happy. What are
you keeping that is so sensitive?

As for cause, as Iain says check your tap water. When we were in London
the tap water was almost always around 50ppm nitrates. Fortunately I had
access to deionised water at work.

Peter