I'm using a fish tank pump too.
There are a couple of benefits from this:
- the fish tank pump is blowing constant and not just when the saw is running
- the blower has a constant blow no matter at which speed the saw is running
- you can dismount the original blowing system, which causes the saw to run much smoother and more silent.
My pump is the smallest one I could get - I think it's designed for a 60l fish tank. That's enough, you just want that sweet spot in front of the blade to be clean, no need for a hurricane in the shop.
You should also mount one of those loc-line blowers. These are fantastic, you can work with that much better than with any other system.
Here is a link to the thread for the modification:
custom dust blower for my saw