Ok a couple of things... As far as cleaning the tank you've got it all wrong. All you need to do are simple, regular water changes. By removing the fish and everytting else you are stressing them out and also probably inhibiting the cycle of you tank (which I bet is the source of your troubles). Just siphon out about 50% of the water whilst trying to get the food and waste in the substrate. As far as the decor, just clean those things on an as needed bases and one at a time, so as to not disturb the tank to much by doing everything at once.
I'm not familiar with any of those additives but my advice is to throw them out, starting with that PH stuff. Its useless for the fish you are keeping. Go to your lfs and get a bottle of Seachems Prime for like 10 bucks. All you do is add a few drops per water change and thats it. It will replace all that stuff you got.