Semi-transparent patches floating on water

[PoolDoc]

Fortunately the previous owner is a chemist and told me he would shock the pool the best way he knew how and that would mean using an extra strong shock formulation containing mercury.

There are NOT pool sanitizers or products containing mercury. I've encountered some brain-dead chemists before, but if he really put mercury in your pool, that would certainly put him at the top of the list of crazies!

This SERIOUSLY concerns me; levels of mercury that are toxic to plants are likely to toxic to humans. You really, really need to find out EXACTLY what he put into your pool. Untill you do so -- and have verified that what he put in is not a danger to humans -- DO NOT SWIM IN IT!

I'm hoping "mercury" was a misunderstanding or a typo. If it wasn't you may not only not be able to swim; you may not be able to drain, without hiring very expensive HAZMAT remediation. Do NOT run out and drain it, in hopes you can do so without getting caught. Depending on where you drain and what he put in, you could face criminal charges if you do so!

I'm modding this in immediately, so Chem_Geek can take a look.