Hydor Koralia 3's, 2 too many for a 40g tank?

[DanG]

the 4's are bigger, closer in size to the seio 620's I'm trying to get rid of, and that would only let me have flow in one spot, with 2 of them, then it's easier to fine tune the flow.

I'm not to worried about the money, tax refund just got deposited, so I've got a bit of money to have some fun with.