I had my in-ground pool (20' x 40') closed last winter by a different
company than the one I used before. They put a few gallons of
anti-freeze into the return pipes after blew the water out (while the
previous company didn't add the anti-freeze). When I open the pool this
year, I added Algaecide, Total Alkaline, Shock, PH+, etc in the first
week at different time. Whatever I put in the pool will cause large
amount of foam (and it's gone after a few hours). Another thing
different was that I didn't see hundreds of worms in my pool this year.
Yes, I got them in previous openings.

My pool used to get clear in 3~4 days. Now, it's been a week, it merely
turns light green. I put total of 3 gallons of algaecide, 25 lbs of
shock in my pool already.

Can somebody explain the worms and foam thing? Could be there a crack
in the return pipe that cause the foam and also allowed the forms to
flee?

Thanks,
-H