I would first of all, buy meat food for the frogs. They REQUIRE bloodoworms, daphnia, maybe some pellets to meet other requirements. I found this link on how to feed them, they shouldn't be fed floating food. (
http://aquaticfrogs.tripod.com/id13.html)
Also, a turkey baster probably isn't cleaning the water so much as it is just removing the visible dirt. Ammonia, nitrates(or nitrites) are harmful and it sounds like you're putting them back in.
With a 2.5 gal I would clean it fully once a week. That's taking everything out and washing it warm water, scrubbing them with a brush. About mid-week you want to take out some of the water pour it down the drain and re-fill the tank with de-chlorinated water. Water straight from the tap is harmful to fish and frogs.
Um, any other questions just ask! If you make these couple simple changes I'm sure your frogs will be fine!