Well, you need at least an ammonia test kit to see what the ammonia reading is. You need to test daily, and probably do water changes daily. Ammonia poisoning can be fatal, and those that survive will have unrepairable gill damage, which will shorten their lives. Water changes are your best bet.
You should also have nitrite and nitrate test kits as well, since eventually the ammonia will be converted into nitrites, which are also deadly, and then to nitrates, which at low levels are safe. So, you need these test kits. And again, the water changes will keep the nitrite down, when it does show up.
I wouldn't mess with the PH, it's a losing battle, and yours isn't that high. Better to let the fish adjust to that then try to change it and have it constantly fluxuating.
It would be nice to know your tank size, filters, temperature, and how many fish/what kind. Makes it easier to help out.
Good luck.