Swamp coolers

Every summer it seems the same. We start out the summer with the swamp cooler working, then after what seems like just a few weeks, it is only blowing warm air. This year we had someone from Kearsly come and "summerize" the cooler so that it would work all summer. No such luck. It still hasn't been working. And of course it stops working in the hottest months. today Ken and I both went up on the roof (yes, I actually climbed up a ladder and got on the roof of our house with no hand rail). We took everything apart. Water runs through the spider arms, through the tube that goes from the pump to the spider arms, and the pump runs. The water in the cooler was the yuckiest looking stuff you ever saw. Ken cleaned out the water and put some clorox in the bottom of the cooler. He said some kind of fungus was making the water look orange. We cleaned the screen around the bottom of the pump. Then Ken put it all back together. It should blow cool air now right? Nope, it is still blowing warm air. I give up. I really want central air now.