Okay, I took everyone's advice and got a few tester kits, I got an ammonia tester kit, and a nitrite tester kit. (Would have gotten a pH tester kit but have "Aqua Safe" which balances out pH issues, might wind up getting it in the end...) The ammonia is at 0.25 and the nitrite is at 0.00. And STILL the male and female platies(And I even caught the Betta doing it) rub on the little cave house we have in the tank with them. They do it every day, and it seems like it's hurting them because instead of doing it all the way really quickly now they do it very slowly, very lightly a few times... one of the females even just sits on the house and rubs her body on it. They're all seemingly healthy, I use "Easy Balance", "Aqua Safe", "Chlor-Out", "Doc Wellfish's Aquarium Salt", and "Crystal Clear" (for when it gets cloudy)... any ideas on why they won't stop rubbing? In my opinion the water is about as good as it's going to get, and I've done a partial water change to remove neutral nitrite or nitrate whichever it is. Let me know, thanks!