On 18/07/10 7:26 AM, Don Phillipson wrote:
Our well water has high levels of calcium and some
rust. So, while the pool is clean and chemically
stabilized, still water overnight reveals next morning
ultra-fine yellowish powder on the bottom. It is so fine it
goes straight through the sand filter and back into
the pool, making the water cloudy and greenish.
Is there any cure for this, perhaps by causing the
dust to agglomerate so that the sand filter holds it?

A flocculent might help, but the long term solution is to install a DE
filter (and perhaps use Fiber Clear rather than DE). A cartridge filter
would also work, and is less of a hassle than DE, especially with the
addition of Fiber Clear (yes, you can add it to cartridge filters to
decrease the particle size it filters from around 10 microns to 2
microns). Sand filters do not filter small particles, which is likely
what's causing your problem.

From
"http://swimming.about.com/od/poolandspamaintenance/a/choose_filter.htm"

"In terms of particle size filtered out, sand is the lease sic
effective method – it can allow smaller particles to pass back into the
pool."

I've got a 4 cartridge PentAir filter and it works really well. It
causes very little back pressure on the pump, in fact unless it's really
dirty the pressure is close to zero. The instructions suggested adding
Fiber Clear to increase the effectiveness of the cartridges.

Depending on the size of your pool, you might even put a single
cartridge filter in series with the sand filter and let the cartridge
filter trap the finer particles. I originally had a single cartridge
filter but it was sized way too small for the size of my pool (40,000
gallons) and I had to clean it much too frequently.

Finally, you might just want to fill the pool with non-well water if you
also have piped in water. Too much calcium is not good for the pool.