In regards to your response #2, If the water is not clear (cloudy) you are to continue the SLAM.Well, not really. Algae is algae and chlorine kills it. You need to reject the idea that your pool is somehow different.......it's not. So, let's get started on clearing your pool.
1. I think you need to open your filter and deep clean the sand. There is an article in Pool School on how to do that. Secondly, check the level of your sand....it should be about 2/3 full. Once that is done, it will be time to SLAM the pool.
2. Review the SLAM article make sure you plan on keeping the chlorine in your pool until the pool is crystal clear. Keep us posted and we'll help.
3. For emphasis, I want to say again that your pool is like my pool and all the other pools. They need adequate chlorine to stay clean and sanitized......you have not been using enough chlorine.[/QUOTE
1. I deep cleaned my sand after I opened the pool (and started having trouble). I don't remember exactly how much sand was in it, so if I continue to have a problem, I'll open up the filter and check again. It wasn't any different than last year, when it worked fine.
2. I slammed at shock level again yesterday with same results that I've had before: overnight test is good (down .5, no CCs), water really cloudy (can't see the robot on the bottom). This has been the case more on than off for weeks. I am continuing to shock (as I did before), but this has been done before without reasonable results.
3. My comment is really to say that this experience with my pool is very different than what it has been for my pool in years past. I really don't think it is just the chlorine levels, but I will keep trying. Here are some other areas of concern:
A. I backwashed the filter before I started this round of shocking. It was dirty (ran the backwash for about a minute and a half), BUT there was no increase in the pressure. I thought maybe there was a problem with the pressure gauge, so I bought another one. Same result today: No change in the pressure even after filtering the pool for 24+ hours. So, maybe this is sand too low? Or maybe it needs something (DE) to filter out what I think are actually white paint particles? Need to stop backwashing and get the sand dirtier so that the filter works? Something else?
B. Pressure at returns is lower than it was last year.
C. Last year, I changed the spider gasket, but had a lot of trouble getting the glued rubber off of the track. I thought it was ok, but maybe it didn't really stick?
I appreciate your help.
There are three criteria to completing a SLAM:
1) Pass OCLT (pass)
2) CC's at 0.5ppm or less (pass)
3) Clear water (fail)
I believe you are prematurely ending the SLAM.
You also reported a CYA of 45, there is no 45 on the scale & you should round up to 50 as the CYA scale is not liner.
At 50ppm CYA your FC shock level for the SLAM is 20ppm and must be maintained there until you pass all three criteria.
After that you need to never let your FC drop below your minimum. I have many kids in my pool, and I am under two large trees so I maintain a target 2ppm above the recommended. If I don't, my water will begin to cloud up, which is fixed by using chlorine.
Are you 100% positive that your FC never reached your minimum level for your CYA?
Maybe you just need to maintain your target FC 1-2ppm higher than what you do currently (once you complete a SLAM).