How do I take care of my little green sea turtles?

I've asked the sales person and was told to change the water every two or three days. I know I've got to do more than that. I would like to build a little "home" for them but don't know how. And, I don't want to go through all of that if I have to change the water every three days. Can anybody provide some info on this?I purchased them at the mall; I don't want to just let them go cause they may not make it. At the same time, I don't want to harm them by not providing for them correctly. Do any of you know if they will get larger than the size of a half dollar coin?

you should free them

oh no you definately need to change the water more often than that..in my experience, i would say change the water once a day..sea turtle tend to get infection easily especially around their feet..so it's pretty hard to take care of unless you really love it..i gave up after my turtle gotten infection for the 4th time and it looked really sick..so i just stop by a beach and free it =/

I would free them...seriously.They are very hard to take care of.I am sorry, but you should never have bought them.

Turtles r really hard 2 take care of and the water gets dirty really often. U might just have 2 free them. My turtles were freshwater and they were hard enough 2 take care of. I usually just put a little dock type thing for them 2 sun themselves on.

I believe all sea turtles are endangered therefore federally protected. Who is selling them?? Unless you live outside of the USA. Otherwise, call a sea turtle sanctuary and speak with a marine biologist. There are many of them in Florida, USA.

green sea turtles are endangered and I would report the store you purchased them at for screwing with endangered species. They do get bigger than 1/2 dollars they grow to hundreds of pounds.