Thanks Richard,
Yes, you're right about me investigating pseudomonas as mentioned in that thread. Since then, I have nearly drained and refilled all the water, and while the most of the water was drained I poured in 20ppm of chlorine in an attempt to not only shock but to completely bomb the water. I then refilled the remaining 2/3 of water. I bought a test kit for bacteria, including pseudomonas and just tested the water yesterday - it came up negative which is good news, but makes me have to investigate further as to the itching problem. I've shocked and brought the values back in line so many times I've lost count - according to the test I don't have any harmful bacteria in the water and and I don't know how it could've survived my many shock and awe raids on the water. I've become so obsessed with solving this that my next step is replacing my sand filter . The pool surface is old and ugly and needs to be replastered next year and the equipment is also old - maybe old chemicals or itch-causing stuff is lurking in the pipes or equipment...I don't know.

However, I haven't tried a bacterial soap and will do that next. Even if the test says I don't have bacteria in the water...if I try a bacterial soap and it works...well, then that would mean the test probably is wrong.

As for the PH, I do have an aerator, at least I think that's what it is. Basically a return that sprays water in the air over the pool. Isn't aeration done to lower the TA without affecting the PH?

Thanks!
Matz