Which vacuum for pool cleaning business?

My friend and I are looking to start a pool cleaning business and need a vacuum. Many I have seen online are like this one:

http://www.aquamasters.com/vacsystems.htm

What would you suggest? What should we be looking for? We will be cleaning backyard gunite and vinyl pools.

Thanks,
John

I live in Florida. All of the pool cleaning companies I've seen here use the type that runs on 12V batteries and has a small motor in the vaccum unit that is attached to a propeller and it sucks the bottom debris up into a fine mesh bag which is attached. Problems I see with the type you are looking at is that if faced with a lot of leaf debris, the cartridge will clog quickly, and you also have to plug it in somewhere. I'm betting it should be a 20 amp circuit and many folks only have 15 amp ones outside, especially older homes, so you may trip alot of breakers. If no one is home at that time, that could be a problem for you and the home owner, depending on what's on that circuit. One benifit of the type you are looking at is that it will filter much smaller debris out and clean better.