Ph level of water changes (aquarium)?

The chemicals you use to change the water don't last. Your water has strong buffers in it that won't be changed. It will lower them shortly and then you water's natural PH will rebound back and that's deadly for the fish. If your fish are locally bought and the fish store didn't import them for you then just leave you PH alone. They are already acclimated to your local water and changing the PH like you are is deadly for your fish. Goldfish will be fine in your local water.

If you want to lower your PH naturally and buffer it to keep it there use a piece of peat moss in the filter box or buy some store bought drift wood and place it in the tank. The brown colored tannis it leeches out will lower and buffer your PH.

If you want to raise your PH then buy some crushed coral or sea shell gravel to put in your tank to replace the rocks and that will raise and buffer your PH to stay high.

Whatever you decide try to keep your PH the same, besides changing 25 % of your water weekly and vacuuming its the best thing you can do to keep your fish alive. Good Luck

Usually a blue reading on the test means Alkaline (7.5+). Anyways, you shouldn't let your PH change like that, it's bad for the fish. Test the water you are going to put into your tank BEFORE you do the actual changing of the water.

Your fish changes it. CO2 makes it acidic. And if you have more than one fish you might need to clean the water often

I actually work at Petsmart so hopefully you don't hold a grudge. Prime and cycle are both great products and you should continue putting them in the tank. I would cut down on the water changes though. Every day? Wow, that is a pain. It doesn't mean the person told you wrong or that it's a bad thing. Every fish expert has their own way of doing things based on their experiences. Water changes are great for your tank, but that is a lot of work. Why don't you try doing about a quarter change once a week? It will be easier on you and it will give the good bacteria colonies in the tank a chance to grow and start settling on the surface before you do a change and remove them all. Just make sure to use a gravel vacuum and take out about 7 gallons. It should be much easier and less stressful on you and the fish. Just don't add more fish until conditions are better. The plants will help, and the fish you already have have pretty much grown accustomed to the nitrates already so they should be alright. Hope that helped!

To tell you the truth, I don't check pH in my tropical fish. Seems like a 25 percent water change every other week keeps things in line without testing the chemistry.