Water in Betta Tanks

Question
I have 2 bettas, each one in their own 10 gallon tank & I use amquel, novaqua & aquaisol for each water change.   Problem is my ammonia & pH.  Everytime I do a water change I have to triple the amount of amquel/novaqua and then use ammonia down to bring the levels to 0. I thought maybe I had bad bottles of the amquel/novaqua so I bought more with the same results (I do use cold water and let it sit for a day or more) I also clean tanks once a week and have no nitrates.   During the winter I have very high ph (I add a cup of distilled water during this time)and now with the warm weather the ph is dropped to about 6.  I keep trying to raise it up, but nothing works. I know they can adjust but they don't look very happy.  Happy pets are what I'm all about (ask my cat & horses).  I don't want to keep putting so many chemicals in their water but I don't know what else to do.

PLEASE I'm at the end of my rope

PS: the amquel/novaqua/aqarisol seemed to work during the winter (although not perfect)

Answer
Your tank is not cycled.

You WANT to have nitrates, because when you have nitrates you have no ammonia.

Here's a nice link, that explains the basics of cycling. Just copy and paste into your browser.

http://www.aquatic-hobbyist.com/profiles/misc/fishcycling.html

Oh, and your pH is fine. Do NOT try and raise up your pH. A super hardy fish like a betta doesn't really care about the pH. The thing that fish care about is the stability of the pH. Your betta would much rather have a pH of 6, than a pH that keeps moving up and down. Just leave it how it is.

-Nick