Will a heater for a spa work for a pool?

I've been keeping an eye on the auction site for a good deal on a used heater (electric) for my pool. I found a good deal for a spa/pool heater. When I looked up the model number on the internet to do some research, it’s only listed as a spa heater. Can this be used on a pool? The listing clearly stated they used it in their pool. I’m only looking for something that will heat my pool (5-10degrees) for a month or so at the beginning of the season and a month or so at the end. I have a solar cover that is on all the time so I don’t think I need anything super powerful.
I’ve looked at solar heat but have no place to put the panels (on ground or roof).

You don't mention what the model of the heater is. It's really the BTU output that you're looking for.
How many gallons is your pool?
How many BTUs does the heater produce?
Do you plan on using a solar cover on your pool?

Think of it this way,
Gallons of water x 8.3 = pounds of water.
Pounds of water x your desired temperature rise = BTUs needed.
BTU's needed/ BTU's of the heater = hours of run time for the heater to raise it to your desired temperature.

If you get over 24 hrs, its definately too small.
As a heat pump manufacturer, we use a cut off point of 15 hrs/day rather than 24hrs. This accounts for the heat loss overnight.

Hope this helps.

It's a Raypak 11KW. I can't find any specs about the BTUs on that model. I wish I could just buy a new unit but because of a new baby my money is real tight.
I have an IG 16x32

1 kw = 3412 btus
11 kw = 37,532 BTUs. Most likely too small for your pool.