For some reason my nitrates have been unusually high in the past couple of months with no ammonia or nitrite. 0 nitrate in my tap water. My tank is moderately planted and I use an Aquaclear 70 filter as well as CO2. Lately, my plants haven't been growing like they used to and I haven't had to do a big trim like I had to in the past. I did notice it right when I started dosing NiloCG thrive after switching from the low tech version. It usually measures between 40-80 even with a 40% water change every week. My stock is pretty low for a 40g breeder (11 neons, 9 corys, and 1 zebra). I had a disease outbreak a few months back but I haven't noticed any dead fish lately that would've contributed to bad water parameters. I do have to vacuum up quite a few empty snail shells every week so maybe those are contributing to a heavy bioload? Otherwise I'm at a loss on what's causing this. Either way I'll up my water change to 50% and see if that helps. I only dose the ferts twice per week even though it says 1-3x and I do more than the recommended water change for my dosing. I've also tried to lower the amount of food I put in.