That’s great about the cdx

I asked because it is better to exchange a hefty amount of water if cdx is in the picture.
If there’s alot of baqua sanitizer in the water this may warrant an exchange as well to avoid plowing through so much chlorine. Water is typically cheaper than liquid chlorine (or other forms of chlorine). So you may consider an exchange before proceeding further to get the level down & this will also dilute the organics in the pool.
The no drain water exchange is the safest option Section 3.5
www.troublefreepool.com
Lots of weird colors & “goo” are produced during a conversion. The sediment may be dead algae but in a weird color? I would vac that to waste if possible.
At any rate the prescription for ridding yourself of both baqua & algae is more chlorine. While you should be dosing during the day & night (as often as possible) - Try to get multiple doses in after the sun goes down/before the sun comes up to help get a leg up in the fight so then you’re just fighting the algae & baqua.