I change water weekly, the tank has been set up and inhabited for months, the nitrates shocked me when I read the test strip bc it’s a pretty heavily planted tank that hasn’t had many issues except occasional ones in the past which were from over feeding I corrected, nothing really has changed, the pleco in question is the newest fish in the tank and kinda small, but has been chowing down today, idk what caused the parameters to swing like this but to answer your question and hopefully lead me to an answer the ph from my tap is 6.8 ish 0 nitrite 0 nitrate 75 hardness it looks like and 0.8 chlorine