Max chlorine in vinyl pool?

Hi all, could use a little help. Here are my specs:
(Taylor test kit)
24,000 vinyl in ground sand filter 24/7
FC-7PPM
CC-0
PH-7.2
CYA-~20PPM
ALK-150PPM
I have been fighting white cloudy water, which I believe is a calcium cloud. I have been having a lot of trouble getting the chlorine levels up until yesterday. Chlorine is provided by trichlor tabs in a floater and bleach(5.25%) or carboys of 12.5% from the pool place. I understand that chlor and CYA are interrelated and have been looking at Ben's best guess chart. My first question is how much chlorine is too much for a vinyl pool liner. I remember reading somewhere never to exceed 8 PPM in a vinyl pool, is this true? Second is it true that lowering the PH help the chlorine kill algae? After 3 days of rain it is now sunny and hot and the water is trying to go green on me. I have been vacuuming to waste, but it is very hard to do a good job when you can't see what you are doing. Any help or advice is welcome, thanks.

According to the chart if your CYA is at 20 you need to get the CL up to 12 ppm to shock it. As far as the level of CL in a vinyl pool , I have had mine up alot higher than 12 without any harm. Like you have seen though , it is related to the CYA level .

THe thing about your pool , I'm thinking you're not going high enough on the CL to have an affect on the cloud. Your ph is good where it is .

I would get the CL up to 12 and keep it there until it holds over night. Run the filter 24/7 and hang in there on those hot sunny days. It will clear and then you can run your CL lower.

Might want to keep an eye on the CYA while you are using the pucks. IT can get out of hand Quick.

Thanks for the help. I'm not too worried about the CYA levels, after ~10 years I know that ours seems to always be low. For whatever reason we struggle to keep it in the 30ppm range. We are on well water and it is close to liquid rock-maybe this has something to do with it. I found this site late last year and switched to BBB. The help I have found here exceeds any pool store I have ever been in, all they want to do is sell you something. I'll get the chlorine level up and keep it there, hope to see improvement soon. Thanks again.