I keep seeing this over and over as I search the net. Mainly that ants are attracted to the electric current.
Tarrant County Fire Ant News
"Fire ants are attracted to the electromagnetic field created by an alternating electric current. This may be due to hematite, natural magnetic material, found in their bodies".
Another page: Fire ants are attracted to electrical systems in equipment as varied as computers, swimming pool pumps, cars, and washing machines. They can cause short circuits and fires.
My only advice to you is that you need to find the mounds and destory the "source". Find a trail of the little pests, and follow them home.
As far as how to go about that. There are tons of ways, I'd just do a search.
My best success to move them away was:
A blended mixture of hot sauce, garlic, lemons, dish detergent, jalapenos, onions and HOT water. It was just anything hot and that I thought they'd hate! They did.
Ants also detest peppermint and cinnamon.
"Never step on or otherwise squash an ant. And never spray an ant with a pesticide. Ants leave a scent when they are injured or killed this way. And, that scent signals many, many more to come to the area where the ant was killed. Vacuum them instead! They won't have a chance to leave their scent. However, if you do squash an ant, immediately clean the area where you killed the ant with a good cleaning solution to get rid of the ant's scent".
Ants will also chew into flexible piping. You may want to contact the pool company, or another one, and see what they suggest you do. It may save you money in the long run. See: Why are bubbles coming into the pool? http://www.electricmotorwarehouse.com/pump_troubleshooting.htm
Ants and mice have been known to destroy pool covers left under decks, in sheds, or garages, etc. Be sure to keep it stored away from them.
I just came across an article by Howard Garrett about Diatomaceous Earth.
In another place I saw this:
"You can sprinkle diatomaceous earth around and in the ant beds. You can get it at swimming pool places and it is harmless to humans and pets. It dehydrates and kills the ants". http://www.stretcher.com/stories/00/000424a.cfm
I hope you get some ideas out of all this.