Is $1,800 to drain and clean a pool a fair price?

It's almost the second week of June, and my pool isn't coming together as I hoped. I'm trying to clean it up and have it ready for swimming ASAP. I've shocked it multiple times, and a robot has been going at it, but there's still plenty of algae, leaves, and debris. Vacuuming is difficult due to poor visibility and a problematic cartridge filter. The plaster is 20-30 years old and needs redoing, but that's not an option this season. I've started draining it but stopped, unsure if it's worth trying to save it for the summer. New clumps have appeared since lowering the water level, which look like pollen. The steps are also just 'cleanish' in spots, not plaster related.