I do water changes regularly once a week, 25-30% on my bigger tanks, and 40-50% on the smaller tanks. I use a vacuum to suck up any uneaten food every morning. I have been taking care not to overfeed, and I don't believe that's the problem anyway.
Someone suggested I test my tap water, and so I have done and here's the result:
ammonia: 0
nitrite: 0
nitrate: 40ppm
pH: 7.6
High Range pH: 7.4
I've had other people suggest getting an RO unit, but I just can't afford one of those at this time. Doing more water changes is going to be pushing me physically because I have disabilities, so what I want to know is, are there any other ways I can help this situation? And I guess I'd like to know if having a nitrate reading of 40ppm will hurt my puffers in the long run? I bought some floating plants because I've heard that they can help alter nitrates. I've done testing on all my tanks and they are all coming out with zero ammonia and zero nitrites, the only issue is the nitrates.
Any help or suggestions greatly appreciated.

