Did I stock my tank too soon?

Question
We recently upgraded our tank from a 15 gallon tank to a 37 gallon tanks. We were given instructions by a local fish store that we should lay down our substrate (flourite/gravel) add new water, add our live plants & decor. Add the water from the old tank, get the water to the same temperature as the old tank and then transfer the fish. (1 small Angelfish, one lyretail guppy, 2 clown loaches, 7 neon tetras and a huge pleco) I confirmed and reconfirmed that we should transfer the fish the same day and they said yes. We moved the sponge from the old filter to the new filter to help with the transition, all of our levels (Ph was at 7 & 0ppm for NH3/NH4) About a week later we were told we could add new fish. We added 3 more neon tetras and 2 drawf gouramis. It has been 2 weeks and now our Ph has dropped to 6 and our ammonia levels have risen to almost .50ppm and seem to be rising still. We have been doing 20% water changes every week but it is not helping so far. I do not know how to lower the ammonia levels. The fish do not seem to be affected so far, they are not gasping for air, and their gills look normal. We did have a tetra die recently, but I assumed that the angelfish got him. Is there anything else I can do to bring the ammonia down? I do not want to bring the Ph up yet until the ammonia is down.

Answer
Hi Kendra
Well, the fish aren't being affected by the ammonia, becuse with a ph below 7.0, ammonia is converted into a less toxic form.  Actually, it's a lucky break there :)  

Did you use the gravel from the old tank as well?  Honestly, sounds like you did everything correct.  The sponge from the old filter was good, that and any gravel, decorations, etc. from the old tank would contain the beneficial bacteria-as long as you didn't let any of it dry out.   

I would just keep doing what you're doing now, like I said, with the low ph, the ammonia isn't toxic to the fish.  Keep an eye on your nitrites though, because those are going to spike, and that will stress the fish.  When you start showing nitrites, up your water changes to daily until the tank finishes cycling.  

Try testing your tap water and see what the ph is reading.  Put some water in a glass and test it immediately.  Leave the glass of water sit out for about 12 hours and retest it and see if it's different.  Sometimes the water companies do something or other and it alters the ph a bit.   

Let me know how that test goes.

Christy