I've heard that using my SWCG to shock will hasten the cell's life expectancy. I don't want to hasten its demise and will probably use good ole bleach on the occasions it may need some shocking--after heavy rains.

I can only run my pump at one speed. It can adequately turn my water in a 4-6 hour period, but I leave it on for 6-8 hours....it usually starts at 8am. Should I maybe have it start later in the morning so that it runs during most of the hot afternoon part of the day and keeps adding fresh chlorine that way?

Based on your comments, I'm leaning toward a CYA of around 50---close to Ben's recommendations and also Aqua Rite's. How's that for straddlin' the fence?

Tell me more about CYA staining??? I added some the other day through the skimmer---tried to dissolve it with some warm water first, but that stuff doesn't like to dissolve, and then slowly poured it into the skimmer while it gulped it down.

I presently have some yellowish stains in corners and the risers of the steps and along the walls in the deep end that appear to be recent. Since we just had it resurfaced with some Diamond Brite in March, I'm very concerned.

We had a bout of yellow algae about a week ago---which I think is gone. (Cleaned the filter daily.)
We did a partial water change to lower the CYA only to find out that the city water was full of phospates....plus I forgot to add a sequestering agent till after it had been filled. Then after going to 4 pool stores and getting 4 different CYA readings of : 15, 25, 30 and 60 all from the same sample, I added some CYA to bring it up to 40. Yes....I do need a life...

So now I'm wondering what the culprit is for the stains:

From the Yellow algae?
From the new water full of phosphates etc?
From the additional CYA?

Other than for the stains, the pool and water look great: clear and blue....sigh..I should be in there right now instead of typing about it....
FC 6.5
TC 6.5
PH 7.4
Hardness 200ppm
Alkalinity 100
CYA 40
Salt 3100