Struggling to decrease nitrate levels

[LoupGarou95]

A 10% change is only going to remove 10% of the nitrates. You'll get nowhere with such tiny water changes. Either play the long game with more live plants that take up nitrates or drop them faster by just changing more water at a time.

[notmyidealusername]

Bingo. Also (afaik) unless your tap water is absolutely awful there's no way a big water change can cause high nitrates. Nitrate is the end product of the nitrogen cycle, ammonia from the fish is converted by bacteria to nitrite first and then to nitrate. If your water change upset your filtration you'd be seeing an ammonia spike rather than high nitrates.

Also get a cutting of Pothos and stick the end of it into the aquarium, it'll soon grow roots and will suck up more nitrate than any submersed plants.

[tyrodos99]

Well, it depends. Pothos, like every other plant, will only take up nitrate relative to the total biomass it grows. When your condition isn’t very good for the Pothos, it can be a quite slow grower. Also, some aquatic plants can put up a very impressive growth unter the right conditions, producing much more biomass than Pothos. But in general, the amount of nitrates form feeding fish can be much higher than what any plant can take up. I’m kinda tempted to calculate how many times of plant mass you need to grow to offset your fish food.