I am looking for a shop that sells good fresh water plants. The more variety the better. Any recommendations?

I have planted tanks in a room. But the temperature of the water is around 30 - 31 degrees. I want to achieve a constant 24 - 26 degree. Which would be a better option? Get an air con for the room and switch it on 24 / 7 or get a chiller? I am just wondering whether what is the electricity cost gonna be like for both. And with chiller, I can only have 1 chiller per tank but if its an aircon i can have multiple tanks but I am not sure whether air con can be switched on 24 hours per day or not.

Please advice.

Not sleeping in the the rom. If you link two tanks, then if any of the tank got water problem, then both also affected right?