Petco does not keep their tanks at 1.017. I have bought from petco and test the water it is definitely not at 1.017. It’s not their policy to keep it that low. Fish only tanks they keep them at 1.022 and corals tanks at 1.025. I know because I use to be an employee and was I charge of all the animals as a companion animal manager. If you have an issue with petco just call corporate let them know their tanks are not up to par and trust me they will send a manager from another store and the market leader to the store that very same day to test the stuff. Well at least in LA. So please if you have an issue report to help improve the stores it does make a difference because the might dollar speaks.