added 'chlorine enhancer' to my pool; now I have no chlorine

[ggilpu]

Back in December when I closed the pool I treated it with a chlorine enhancer. After that none of my chlorine tests (DPD, OTO or strips) worked, not even now 3 months later.

Any ideas? I know there is chlorine.

[PoolDoc]

If there is chlorine present in any form, OTO (clear -> yellow drops) will show it. If OTO shows nothing, you've got nothing.

"Chlorine enhancer" is a marketing name, not a chemical. It could be anything, but most products described like that cause serious problems. What "chlorine enhancer" did you use?