Sjasmin888
Aquarium Advice Apprentice
I have two 20 gallon tank setups, one heavily planted, the other lightly planted. They are both slightly overstocked, but cycled. I do water changes of around 30% every 2-3 days but recently my nitrates have just refused to go down properly. I have started doing water changes of around 50% the last few days, but simply can not get the nitrates below 30ppm. I have tested my tap water, and even let it sit for almost 10 minutes, checking the color frequently, but it doesn't have nitrate. What on earth is going on here?