sorry if i come off like an ahole im not trying to im just being very to the point. my guess is if you go get a test kit tomorrow youre still going to be atleast 40ppm on nitrates. so i would do 25-50% every other or every second day until they consistantly measure below 20ppm then stick to 50% weekly water change. or reduce your bio load.
Here, convicts can live with tons of different water conditions, it doesn't look too bad, whatever it is. But I do second water changes at least everyso often.
no perfect perfect you are not being a ahole i would rather save my families fish than to hear what i wanted to hear and thank you all i will buy that kit and i will make sure i take all the precautions i can so it doesn't get any worse