Read through your thread, and my thought is a filtration problem, and maybe a little impatience problem

There are definite stages to a SLAM. The first stage is killing the algae and that's where you will see a large loss of FC initially. The second stage is attacking the stragglers....this is where it is important to brush, clean ladders, behind lights, etc. The final stage is where you probably are, and that's clearing the pool of all the dead algae. This stage can be the most time consuming depending on how optimum your filtration is. A few tricks you can do to speed up the process:
Add about a cup of DE to your sand filter through the skimmer basket. Watch the pressure to make sure you don't over do it. DE will filter out smaller particles than sand alone and will help clear the pool.
Turn the pump off one night and let as much of the gunk settle as possible. That will A) let you see how much dead stuff you have as it will settle on to the bottom of the pool, and B) let you see that without the suspended particles your pool is clearing up. Then CAREFULLY and SLOWLY, vacuum the entire bottom of the pool to waste. This might take a couple of refills but it will help rid the pool of a large quantity of sediment faster. I had two mudslides into my pool along with a high iron precipitation event, and this technique worked for me.
Also, just to give you a gauge, on the iron precipitation event it took me 10 days to clear up and I had no Algae.