high nitrate levels

[liquidforce5010]

i have to 6" plecos and 4 baby cichlids in a 40 gallon tank that has 40gal filter and 15 gal filter on it and recently the nitrate level has spiked to 180mg/l. I have used an entire bottle of prime over the last week and have done 2 like 40% water changes and it hasnt gone down at all....any suggestions...The tank used to have some big cichlids a big birchir and a freshwater moray but i moved them to a new tank about 2 or 3 weeks ago because this one was to small...

[AhKwaB]

If you didn't clean the substrate and filters well after the move of the past fish then that could be where your problem lies.
Also prime will give skewed readings with certain test kits.
Your water source can also contribute to the problem as well.

[liquidforce5010]

im using an api test kit, i put new filter catridge's in both and used a gravel vaccumn for the substrate for both water changes

[liquidforce5010]

and the prime doesnt seem to affect the test kit when i test the water from my 75gal also the tank is planted....would adding more plants help?

[allysangels]

plecos poop alot, and there is probably left overs from the carnivores. keep on doing water changes until levels are back down again. depending on the species of cichlids, have you considered adding some hardy plants to mop up extra nutrients?

[Totenkampf]

that doesnt sound like that drastic of a fish load but if you are getting high nitrates and nh3/no2 are still good then at least the bio-filters are working. i have always been a fan of emersed plants growing in fish only tanks like this. i had a refugium on a rainbowfish tank and it seemed to export no3 really well if i used fast growing plants that can handle bog conditions like pothos, synogonium, aglaonema, or spathyphyllum. riparium planters would work too

[troy tucker]

Are you over feeding? What filters are you running and the media in them? When were they cleaned last? Do a bigger W/C 90% or more.