16x38 inground vinyl liner approx. 20,500 gal, 3-6' deep hayward sand filter. I have 5 problems upon opening up this summer: water cloudy, worms, stains, blue debris, no chlorine reading. Abundance of worms present (see attached photos). Steps and Seat stained blue - the blue stains seem to come off with severe scrubbing, and they also lifted after applying pool stain treat (a sequestrate) directly to the area. But it did not clean the walls of the steps bc the product needs to sit directly on the stain to lift it. There is some debris floating through the water and large amounts of this debris floating on bottom of the entire pool it appears white and in a granular form when looking into the pool, but we scooped some out with a paint strained covering the skim net and its actually a light aqua blue color extremely fine and not granular at all. I don't know if its live algae, dead algae, or a severe overdose of the Eclipse 3 algaecide i use every year that broke down while pool was closed. There are also some random round yellowish brownish stains along the back of the steps, also the white skimmer box face plates from the water line and above are stained a yellowish color. The place that is under the water line remained white. The skimmer box lid on the deck also turned yellow, but only half of it (the half that is under the cover. We have a solid safety cover for 4 years. the first two years the pool would open crystal clear and we would swim same day. Past two years we have had the issue described above, but this year it is really bad. Last year the chlorine readings were high all summer. But i had to add PH several times. This year, we have no chlorine reading at all. So far to clean up we scoped worms with leaf net, vacuumed the rest to waste. We filled back up, added liquid chlorine, ran filer 24 hrs. No changes. Still no chlorine reading. Took sample to store, all levels ok except zero chlorine (prior to us adding), but had stable cya. Pool store explained everyone coming from our area is having the same issue with no chlorine readings, and that something environmental is happening that no one can explain but he is the store chemist and it seemed odd to me that he wouldn't have some other chemical theory as to why. Ive read on your site that while pool is closed soil bacteria can get in pool and turn your cya to ammonia which causes chlorine to disappear immediately and not read. if its not ammonia then its algae with a huge chlorine demand. The worms we had in the pool also brought a good deal of soil with them so I'm wondering if this is the case. My brain is in a million directions sorry this may be the longest post ever LOL, I'm totally overwhelmed. PLEASE HELP, thank you.