My Name says...

I'd like to thank you all for the great information you
gave on this subject. I have had a pool for 20 years
and never heard of the phosphate thing before - I'll
have a pointed discussion with my pool store about that
one. I'll follow up with the group in a couple months,
the cover won't come off until memorial day week end.

The phosphate thing was never a problem here until the
mid-1990's. Well, except for people whose lawn service
broadcasts a regular supply of fertilizer into the pool.

But gradually everybody started having algae problems.
Over time, the cause became clear - the phosphates were
now in the water supply. Not enough to affect potability,
but enough to significantly raise the levels in pools.
Algae absolutely needs phosphates to grow, but it only needs
a tiny amount.

And the source of the phosphates - chicken ****. Seriously.
A large number of poultry processing operations moved into
the watershed, and the "waste" was converted to fertilizer
that began to be widely used by area farmers. It's high in
phosphates, and just runs off the fields into the creeks and
rivers, and eventually into the lakes we draw water from.

So now pretty much everybody uses PhosFree, or some
equivalent, based on the free testing the pool stores
provide, and it really works well. But in your area, it
might not be a problem, depending on the tap water
situation. On the other hand, it doesn't take much lawn
fertilier to get you in trouble if it contains phosphorus.
Superchlorinating will neutralize the ammonia, but not the
phosphates. Anyway, testing your pool water will tell the
story.