What do you do if you have shocked your pool seven times but there is still algae?

You could try taking out water and replacing it little at a time. Do not drain the whole pool it could damage the outer walls. Try a sump and then replace the water at the same time with good clean fresh water, it might take a while but eventually the algae will have to move on...Also are you sure its living algae and not dead because it could be just stains from the old stuff. Improved answer to the first question. Living Alagae or dead algae stains you still have to resolve the first problem and more clarification will be needed about the pool surface to resolve dead algae stains. Sell the house! Well it is not that bad really. If you have only shocked the pool and done nothing else and it is not showing any improvement then the pool needs more that a shock. I would recommend taking your water to a swimming pool retail store that does free water analysis. Check with your friends and neighbors and see whom they like to use. Here are the possibilities. Fist the water chemistry is just way out of wack. If the pH level is to high the chlorine will not do you any good. I don't care how much chlorine you use nothing will happen the pool will stay green. If the calcium hardness is too low (below 100 ppm) the pool will stay green no mater how many times you shock it. So these balances need to be check and dosages recommended by a professional. Phosphates could also be the problem if they are 150ppb or above. Second if the water is perfectly balanced and the pool is still green you have a filtration problem. The filter media (sand, cartridge or Grids) could be the issue or the multiport valve (if you have one) could be an issue. Again with equipment problems consult your favorite local pool dealer. If want more help here please be more specific about your equipment and I will be happy to help. I hope you get to enjoy your pool soon! The Guru of Pools at Discount Pool Warehouse.com