You're not going wrong, it just takes some patience and persistence to get it all cleaned out. The quicker you can get the debris off the bottom, the quicker you can get the water cleared up because all your chorine isn't being wasted trying to sanitize the junk on the bottom. IF you can get a leaf net and just net as much of the stuff out as you can, it will help. The stuff has to come out of the water, and you can either net it out or let the filter get it, but that's going to mean very frequent cleaning for awhile. Adding bleach to 40-50 isn't going to clear it any quicker than bleaching it to 30 and holding it there--you just need to concentrate on getting the debris out. It takes work, and it is not a quick process, but it will work if you can stay the course..

Janet