pH is off. Low pH leads to hyperactive chlorine activity. In short, a low pH will have you burn through chlorine much quicker than if it is in range. Conversely, a high pH is just the opposite. You may test and see a lot of chlorine in your pool, but the chlorine isn’t ‘releasing’. Briefly, a proper pH will go a long way in keep algae away.
Stabilizer is low. With all the rain we had this summer, there has been a lot of pumping water out of the pool. When you drain water, you take the stabilizer with it. On a traditional above ground pool, you probably drained as much as 15-20” of water out this summer. That’s nearly half your stabilizer too. Stabilizer adds life to chlorine and minimizes the chances of chlorine.
Water temperature. As water temperature rises, you need more chlorine because it gets more active the hotter the water. Here’s the rule of thumb: For every 10 degrees of water temperature rise, you need 25% more chlorine. What worked at 70 degrees won’t work at 80…0r 90. You constantly need to adjust your chlorine input and if you combine this with points 1 & 2, it spells trouble.
Bring us a water sample and we’ll be grad to do a free water test and keep you on the straight and narrow. –Max
Eastgate Pools & Spas