So I have a inground vinyl liner pool that is 35,000 gallons with some problems. I apparently don't know what I am doing. I have a rather large pink algae problem (the pink/purplish bacteria), it was this spring on all surfaces. it didn't seem to be going away with opening shock or subsequent shocks (I thought I was keeping at around 10ppm, but now am not completely sure). So I went off half cocked, read some things on the internet (not this site) and put several bottles of bromine tablets because I thought I was dealing with chlorine resistant bacteria. That has seemed to work after multiple scrubbings and latest bromine application (4 days ago). At this moment the pool doesn't look bad. But after discovering this site I now realize I screwed up with the bromine. I also discovered that my CYA is sky high (way over 100, maybe even twice that) and that is playing a part.
My levels that I checked this morning were as follows:
FC - 3.5
CC - 3.5
CYA - >>100
Ph - I didnt get a chance to check this AM, but its been running low on test strips like 6.8 or so
Alkalinity - again didn't get a chance to check level today, but its been running low

My question is this. Do I have to drain my pool? I know it would kill 2 birds with one stone (the high CYA and the bromine ions), or could I continue to shock the pool and maybe drain some water to try and lower the CYA? My pool gets full sun by the way for 12 hrs. Thanks for any help!!