High Nitrates

Nitrate levels aren't as critical as ammonia or nitrite and don't need to be at zero. In fact it's unlikely you'd ever have nitrate levels of zero as water out of your tap probably contains some. 80ppm is on the high side but not the end of the world. I believe it's generally recommended to keep nitrate levels below 40-50ppm. Also the 80ppm reading doesn't necessarily indicate that there's a problem with the filter as the bacteria in the filter don't remove it (although you can get filter media which is supposed to reduce nitrate levels). Best way to keep it down is just through regular water changes. The addition of live pants can also help as they will use the nitrates as part of their growth requirements and some are particularly good at 'hoovering up' your nitrates.

It could be the shock of moving them making them swim a bit odd. Tetras and barbs aren't usually affected by nitrate in the 80s. There are some fish that don't like high nitrate, but if you google what you have you'll soon find if you have some.

Test your tapwater nitrate - that's the lowest you'll get it by water changes.

I've heard Hornwort is good as well, although I haven't had any of this myself. Elodea tends to be fast/easy growing so is likely to utilise a lot of Nitrates as well, although it isn't the most attractive plant going - good as a starter plant though.

Nitrates are basically the price we pay for biological filtration and shouldn't really be obsessed about too much. What Sue says is basically true but misleading. (Oh God, I'm 'sort of' criticising her post!  Please forgive me all knowing one, it won't happen again!)

Test your tap-water nitrate - that's the lowest you'll get it by water changes.

This is true as far as it goes, but in order to get your tank nitrate down to the tap-water levels, you may have to do a 100% water change. A more realistic target for nitrate levels is the tap-water level to tap-water level plus 25-30. And remember, tap-water levels are not a constant value.

Don't forget that the nitrate test isn't that good, can be misleading. In any case, nitrate levels within reason are not that critical and testing for ammonia and nitrites is much more important, The main problems with nitrates seem to arise when introducing new fish which have been kept in a low nitrate environment. It is always a good idea to test for nitrate before introducing new fish and do a large water change if necessary. Fish already in a tank seem to adapt to higher levels provided the change isn't too fast.

I've had to postpone my trip to buy fish today. I was doing a final water check and amonnia and nitrites were fine but the nitrates were somewhere between 80-160ppm. I did a 50% water change which took it down to somewhere between 40ppm & 80ppm and then tested our tap water and that was 40ppm. Can I be happy with this result and add some fish tomorrow?

Thanks Sue, I'll re-test tomorrow before we leave. We'll get x6 Glowlight Tetras tomorrow and go from there.

I'd read up on dwarf suckermouths on wiki and other fish sites, which were the first fish we were going to add and acording to stats they should be ok, what I hadnt done though was look on other forums, the poor fish have an horrendous death rate and are actually really hard to keep.

Several lessons learned by me today, all thankfully pre fish.