You're totally right Anna; my testing kits limitations force me to "guesstimate" the current chem levels. Thankfully, with 2 different test kits (drops and strips), + occasional pool store tests + visual inspection of the pool, I think I'm operating on a bit of information, although it is indeed a lot of guesswork (and hope!!). I would love to have a sophisticated kit, and will certainly look to acquire one this summer. Can't believe how many pool owners and even some pool stores are using almost pre-historic testing!

I am happy to report that there was a LOT of improvement overnight, after the latest agressive shock treatment, with the addition of 4 gallons of bleach (10% active chlorine). The water has turned from green to pretty almost turquoise overnight!! Very encouraging. Visibility has improved to almost 3-4 feet, although the water is still blurry/cloudy of course. I now have a cloudy but turquoise pool, with almost to remnants of shades of green in the background. THe battle ain't over, but the green monster has become a turquoise wounded beast and it is definitely retreating.

Latest tests show that Chlorine levels are holding up definitely over 12ppm here at noon in full sunlight (dunno by how much over 12ppm... again testing limitations... but from the look of things, it is above 15ppm)

I am short on time today, but I believe I will be able to be much more effective on the cleanup job in the next few days and over the weekend, since visibility has improved and will keep improving hopefully. There doesn't seem to be that much debris after all, from the look of things, although the deep end (over 8' deep) is not clear enough to be 100% sure. Filter is doing well, backwashing every other day at this point (whenever it raises by 4-5 PSI)

We're moving on to phase 2 of the battle. Now I want to eliminate the "cloudiness" and improve true visibility. I am assuming that close monitoring of essential chem values (pH and Cl, as well as keeping an eye on CYA) will be key, as well as maintaining strong Free Cl levels (well above the 10ppm mark)...... and eventually the cloudiness will subside?

I am not yet considering adding algaecide, as you've made the point that it might be wasted on such high chlorine levels anyways.. and besides, Chlorine remains one of the best algaecide. I'll save the algaecide I have for maintenance and prevention of recurrence.

Cheers and thanks again for the support!!