PattysAquatics

It’s 75 gallon with South/Central American cichlids my plants are dwarf sag, anibus , java fern, red scarlets, pogostemon octopus, and a couple different cryps. Using easy green, easy iron, and carbon. Have a cannister filter , hang on back with pothos and sponge filter for filtration and fluval 3.0 plant for light set at 30% running for 8 hours which I just dropped from 10 hours

Ok so I have got either a black hair or bba started in my tank. I read some other threads on this forum about ways to battle it. I did a water change on Sunday then tested my water on Monday and was at 20 for nitrates. Tested my water again today( Wednesday) and it was at 40. Now I have pothos in my hang on back and a lot of newly required plants from the best place of all time to get plants Aquarium Co op of course. ( couldn’t help myself)So I was hoping to only have to do one water change a week. My question is I’m assuming my nitrates will continue to rise unless I do a water change. Will keeping my nitrates around 20ppm help keep the algae at bay or am I wrong in my thinking.

Any ideas on the sex of these green terrors? Got them about 5 months ago and have noticed there colors changing.