It is an inground plaster pool. I know not to drain the entire pool, the guy that re-surfaced it told me what happened to a customer that did. haha

How much is a partial drain?

By shocking I was putting in a couple of scoops (the big blue DE scoop) of granular shock for a few days just trying to get the chlorine level up to kill what I thought might be algea.

Thanks for the input!