Consistently high nitrate

Performing a 50% water change should cut the nitrate in half regardless of what is causing your high nitrate reading, especially if your tap water is showing zero nitrates.

Don't take this wrong but is there someone else that can compare the color of the nitrate test vial to the API test card?
 
Performing a 50% water change should cut the nitrate in half regardless of what is causing your high nitrate reading, especially if your tap water is showing zero nitrates.

Don't take this wrong but is there someone else that can compare the color of the nitrate test vial to the API test card?

No offense taken, and I have already asked my sister if she could color match the vial to the card.

I took the marimo balls out when I rearranged the tank. I also took out the Christmas moss balls, and one of them had become partially untied and the styrofoam was threatening to break out. I took out the styrofoam and tied the moss around the rock that had been anchoring it. I rinsed the marimo balls out in some tank water, and didn't see much debris at all.
 
i suggest that you find out what the nitrate level really is. from the description (i've never used that test set) it is reading "infinite." take about a pint of water out and test it. then pour out half of it, replacing that with tap water (which you say reads "zero") and retest. keep diluting and retesting until you get to a number that is actually measurable.

rapid happy plant growth is certainly consistent with high nitrate levels, but happy fish are not.

perhaps it isn't really nitrate. try to contact the test kit maker and ask one of the technical guys if they know of anything that gives false positives for nitrate. it could be that you have something in there which is sourcing some obscure salt with does not bother the fish but really annoys test kits.
 
Update. Been battling this for a while, and can't seem to get to the bottom of the nitrate. I drastically cut back on feeding, and it seems to have unintentionally thinned out my ghost shrimp, but I haven't found any dead ones. Fish are still acting normal, no signs of distress, healthy appetites, and still very active. BNs are doing the courtship thing - or at least that's what I've been told - but thankfully no breeding at this time.

Just did a massive water change, pulled out the marimo balls and squeezed them out in a bucket of tank water, and got a ton of stuff out of them. (They were relatively clean last big WC.) Also shook out my filter media in the dump bucket, but didn't replace any of it to avoid an ammonia spike on top of the nitrate issue. Also removed the ferns because they weren't doing so great - the moss had really grown out and was entangling and shading them. Pulled some more moss out too, as it's growing rather quickly and was getting too close to the filter intake.

I also moved decorations and vacuumed up all the debris I could find, refilled the tank, then vacuumed again.

Tested last night. Zero nitrite, negligible ammonia (between 0 and .25), but nitrates are still up around 40-80 (the colors on the card are very close, and the test vial is bright candy red). Plan on siphoning out more water tonight after work, but am wondering if the mopani leaching tannins can affect nitrate. I soaked the wood for roughly a year before using it, but it still leaches out some tannins. The wall behind the tank is dark avocado green, so the discoloration isn't noticeable until I siphon water into a white bucket. However I do notice how much brighter my tank looks when the tannins are substantially diluted due to a water change.

Could tannins contribute to the nitrate reading?
 
I vote no on the wood. Did I miss what your tap nitrate levels are?
 
wait..styrofoam?
 
The styrofoam is the core of the Christmas/java moss balls that "float" in the tank. The moss is wrapped around the styrofoam and then wrapped and tied with fishing line, which is then wrapped and tied to a rock to keep it weighted down. The moss ball then "floats" submerged in the tank. I didn't know it was styrofoam until I took one apart to tie moss to my mopani. Another one started falling apart due to my BNs knocking it around, so I took the styrofoam out and retired the moss around the rock weight.

I siphoned about 7-8 gallons last night, refilled the tank while the siphon was still going, and then tested nitrates. Vial was more orange this time (20-40 range), but still looked higher than 40 to me. I didn't change filter media, but I am seeing some particles suspended in the water, so will replace the filter pad today. Filter is a Whisper 40i. I did not test ammonia or nitrate last night, because I'm pretty sure it wouldn't have changed much over the past 2 days. (Tank set up in October, fully cycled and established.)

Will siphon more water tonight after work (same method - airline tubing into 5g bucket). Tomorrow will be dedicated to tank maintenance and dropping into the LFS for supplies not available at work.
 
depending on the manufacturer of the stereo, it could be leaching stuff...no proof, but just a thought.
 
I only have one floating moss ball in the tank. The others were taken apart and tied to mopani/rocks. The remaining ball is fully intact, but if I can't get the nitrate down, I'll take it out and test the theory.

I do have some Purigen I'm considering putting in the filter. Or NitraZorb. Just wanted to try getting the nitrate down before adding anything else, because I'd really like to know where it's coming from.
 
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