Hi! Unfortunately I missed your thread when it was posted, but the ph issue makes sense and I'm glad you caught it. Personally when I keep tadpoles I initially keep them in the water they were found in, which I manually cycled out for treated tap water every other day or so, removing around 20% each time, to allow them to acclimate to the new water conditions. I keep them in small groups in deli cups. Once the water is essentially just tap water I can make full switches easily. To be honest though, the work to maintain them that way, especially with a lot of tadpoles is a bit much, and I'll probably be using a filtered tank next time myself. I'm really glad your tadpoles pulled through and made it to metamorphosis. Also, nice imgur album.
Edit: almost forgot: Over here in California Greys are a fairly common cheap treefrog in the pet trade, while the local frogs I keep, Pacific Treefrogs are nowhere to be found(saw some once at a shady pet store, likely wild caught or collected as tadpoles.). It makes me wonder if in other parts of the US Pacific Treefrogs are commonly available.