update: that was my problem with the green coming back. Once I held the chlorine at 15ppm for several days, then vacuum to waste thru pump/filter. Then turn off pump for 24 hrs for the fine particles of algea to settle and vacuum to waste with a 5 gallon bucket, not thru the pump/filter. This was the end of my green battle! My pump is still running, we still bang on it with a rock if it wont turn on and it starts pumping.............However it still does not seem to filter out anything other than leaves or large bees. I still have to vacuum thru filter with someone holding pantyhose or a knee sock (or both) over the return to filter out everything except the small particles of dead algea. For the record, NOTHING will filter the tiny bits of green algea. I held every type of fabric I could think of over the return to try.......green water blew thru everything. Silk filtered it the best but the water had such a hard time getting thru the silk fast enough that it would fill up my fabric "bag" and eventually burst at the seams or if not then even my strong hubby couldnt hold it over the return. Even for as long as he could hold it on there, green water would seep out anyway. I ended up putting floc in the water, letting it filter for the day, then turning off pump for 2 days and then vacuum to waste with the 5 gallon bucket method. That was the cleanest and clearest I got my pool all year. Its still not crystal sparking clear but all the green is gone, you can easily see to the bottom. It has an over all clear look but when you look very closely or when a light is in it at night you can see tiny bits of "something" floating in the water. I would say it was pollen but last year (the first year) it never did this. I still think my pump is too strong for my filter and when this one goes out I plan on replacing it with a smaller one even though all the pool places still recommend one this size for my pool. Thanks for all the help, we finally got the pool under control though it was disheartning how many swimming days we lost, not to mention the higher water and electric bill with all the vacuuming to waste and refilling.......sigh, but now I am more experienced