High nitrates- under gravel filter....

[FishyJames]

I have a 29 gallon with an under gravel filter with about 3 inches of substrate. (Eco complete)My nitrates have been real high.....off the ati chart.  I have done 2 60% water changes and vacuumed the gravel and got the nitrates down a little.  The tank is planted and I don't add fertilizer due to the high nitrates.   Is there anything else I can do besides more gravel vacuuming and water changes?  Should I still fertilize with a already high nitrate?

Ps.  My albino cories like the water changes....eggs everywhere with at least one baby bouncing around the bottom.

[CJs Aquatics]

I have some undergravel filters on 29’s with deep substrate as well. My first thoughts are you said you did water changes which is what I would do first, do you do them regularly? From there pictures of the tank would help with diagnosis but to tide you over in the meantime perhaps there are some very minor suggestions. Is the tank being over fed perhaps? Is it newly set up or has it been established? Has the stock level or plant level changed or has any additional filtration been added or removed? These are my first thoughts. If it’s newly set up it perhaps could use some time or additional bacteria to help things get going, if it’s been established and this is a new issue I would think to myself what’s changed recently and make a list. If nothing has changed recently perhaps the equipment itself needs serviced or something that’s been in the tank like the substrate is the issue. Perhaps if you use water that comes from a facility they added something to it and that’s causing the issue. I would monitor the inhabitants which it sounds like you are and increase water changes to daily until things become more manageable maybe 15% or so a day and see how that goes. Could be a number of things causing the issue, would need to know the complete breakdown of everything going on with the tank to properly diagnose however I think you are already on the right track, I personally wouldn’t fertilize bc I tackle one issue at a time and right now the focus for me would be water quality rather then plant growth unless they are in some sense main filtration… hope something in this helps random parameter shifts are always stressful 

[FishyJames]

Thanks for the thoughtful reply.  I will do daily water changes until resolved. I must admit I had neglected the tank for the past few months.  It is heavily planted and I though that would keep things balanced. 

[FishyJames]

I had to do four 50% water changes to get my nitrates down to 30..... very neglectful on my part...

I installed 2 small powerheads to my undergravel filter to increase filtration.   Now the water lettuce isn't liking the increased flow.  What floating plants don't mind some surface movement?