Tadpoles, my have they grown!

[charlamanda]

Since I have taking the tadpoles in from the pool they have been growing fast. I now have 30 and most have doubled, tripled and even quadrupled their size. Here are a few pics from 10/21 and when I first took them in for comparison 10/13.
I was wondering if anyone has any suggestions what to put in the tank with them so they can climb when they grow their legs. None have any yet, but I am sure they will start very soon at this growth rate.
The first 3 pics are from 10/13 (21) and the rest are from 10/21 (30).
I am changing the water every other day and I don't treat it, since it's well water, I only let is sit for 24hr to bring it to room temperature. I am feeding them fish flakes I add water to and swirl prior to dumping into the tank so most of the flakes will sink to the bottom. I only feed them once a day, which seems to be enough. I don't have too much experience, since the last batch I left in the pool and only had to add water to the pool when it got too hot or evaporated, There was plenty of algae and leaves for them to eat.
Any advice or suggestions would be helpful.
Thanks.