Can't lower nitrates - Help!

[benjamin01]

Just wondering if anyone has some advice on extremely high nitrate levels.

Just finished fishless cycling a 3ft tank and did a 100% water change yesterday to lower the nitrates which were 80ppm+. I checked the levels two hours later after the major water change and they had lowered to 50ppm. Checking them again today I found that it has gone up to 80ppm+ again.

Can anyone offer any insight into why the water change only lowered the nitrate levels a little and why it has risen to 80ppm again?

Using the API liquid freshwater kit.

There's no traceable amounts of nitrate in my tap water.

Thanks in advance.

 

[Quentari]

Do you have any fish in there yet? are you still adding ammonia?

I've found with the liquid tests anything over 40ppm tends to all look the same shade of red, so there's a possibility it was higher than 80 to start with. Not sure why though, unless you added too much ammonia. But I'd guess you would notice doing that.

Adding a second filter and/or some live plants may help out with the nitrate levels.

 

[layna]

Im sure you were unaware, but a major mistake you have done, is finishing a cycle then doing a 100% water change, this will have a negative effect.

You should never need to do a 100% water change unless you are wanting to start your cycle from scratch.

If you have really high nitrates, then the best thing to do is do 20-30% water changes every day until they lower themselves.

Do you have a filter running 24/7?
Is the filter large enough for the volume of your tank (your looking for a rate that turns over the volume of your tank approx 4 times and hour, so a 100L tank needs a 400L/ph filter)

From now on just do the partial water changes once a day and the nitrates will start to fall, but if you dont have any fish in there dont forget to put a small dose of ammonia in everyday to keep your cycle working

Another option you can look at to help with nitrATEs is to invest in lots of plants for your tank, but this wont mean you can skip weekly water changes or anything, just every little helps

 

[benjamin01]

No haven't added my axolotls yet trying to get it perfect for them. Just adding 1ppm of ammonia every 24 hours.

I have two filters running 24/7.

No I had no idea a large water change would put me back.

Thanks for all your help, I'll start doing partial water changes

 

[layna]

Glad i could help
Its not the removal of the water its self that is bad, but removing the water starves the 'good bacteria' in your cycle (that grows on the filter, tank walls, ornaments and substrate and then through starvation it dies, so when you add more water and fish ect it has to start all over again.
I would advise against scrubbing the ornaments too, and only wash your filter sponges ect in a bucket of tank water, as the chlorine in tap water will also kill your bacteria, thats why its important to use dechlorinator in every water change or leave your water out for 24-48 hours.

If you have any more questions, and you dont want to post on the forum, check out the IM boxes at the bottom, or pm me and ill try to help