First, thanks to John, Jan and Carl for your insight.

Now, if you can stomach them, some subsequent events.

I again cleaned the cartridges. They were coated with a light yellow crud, kinda like a flour and water mixture. (This was less than 3 days after the previous cleaning.)

Then, just for yuks I guess, I took a water sample to our local pool store. Drum roll, please.

I hasten to add that my pool-store folks seem competent and, I think, honestly believe in what they tell/sell.

My PS 234 readings were very close to theirs (exception was ph; they said 6.7 vs. my 7.2) I was told my TA and ph were too low. Correct these and then shock, sez they. They recommended 10 pounds of baking soda, er, excuse me, "Biogard Balance Pak 100" to raise TA and Balance Pak 200 to raise ph. They told me liquid chlorine would be fine for shocking. I proceeded to buy some goggles for my daughter, but that's all.

Anyway, I have added baking soda (perhaps 2 pounds) and will add 4 gal of 10% LC as Carl suggested.

Cheers and thanks again,
Paul
_ _ _ _ _
Nothing is better than the unintended humor of reality.
Steve Allen