Cleaning up is much harder than running a cleaned up pool.

A *SINGLE* episode of algae will often consume more than a month's worth of chlorine! And, mustard algae is the worst. Plus, for unknown reasons, some pools tend to have recurrent episodes of mustard algae.

The fact that you lost 5 ppm overnight strongly suggests that something is still going wrong in your pool. You need to continue raising the chlorine overnight, till the overnight loss is closer to 1 ppm.

Regarding liners, there's no particular answer. Liners vary greatly in susceptibility to bleaching, even within a single manufacturer's product line, and the details that would allow you to predict which is which are generally known only to the companies printing the vinyl sheet stock -- which are NOT the same as the companies making the liner.

The mustard algae guide is here: http://pool9.net/mustard .

And . . .
Quote Originally Posted by PoolDoc View Post
Anyhow, if you would, fill out these two forms, so we can be more confident we're not overlooking something:
http://pool9.net/pf-equip-form/
http://pool9.net/pf-hist-form/