ok will try to answer
No never added a chlorine remover
No floating algae
Never added any yellow out or yellow treat
Did not take any readings last fall when closed thus unsure of cya reading
Do not have copy of initial readings but when pool place opens in morning will see if we can get copy-ok
Today added 6x1.42 gals of 6% and was able to get a chlorine reading with the strips as a quick check about 30 minutes after.
3 hours later none
Added another roughly equivalent to 20 ppm - checked and was able to see on strip
3 hours later none on strip but on chemical tester appears free chlorine was betrween 2-3.
Will hit it again once done mowing the lawn

Have added areator or will plan on treating every 3 hours until bed and then give you complete set of readings in morning-OK

Last shock it did load up the filter so something came out of the water