white patches on bottom of pool

The bottom of my pool has a white patchy look to it. The pool is painted a dark blue so the white patches show up very well. When I brush the bottom a cloud erupts but the white patches do not go away. No amount of vacuuming will remove the white patches. the pool is plaster/gunite bottom with fiberglass sides.
I use a Mineralize Model 401 by Lifeguard Systems for my purification keeping a copper level at .2 to .3. PH, Total Alkalinity and Calcium Hardness are all balanced where they should be. The water is crystal clear.
Anyone have any idea what the white patches are and how to get rid of them.
Thanks for any help

Hi Jim;

If you hang out here long, you'll find that we pretty much ignore statements like "Total Alkalinity and Calcium Hardness are all balanced where they should be". Instead, we pretty much always say something like, "show us the numbers!" and then go further and demand that the numbers come from a drops based test kit.

+ Here are links to the kits we recommend:

HTH 6-Way Test Kit @ Walmart
Taylor K2006A (3/4 oz bottles) @ Amazon
Taylor K2006C (2 oz bottles) @ Amazon

Meanwhile, if you can collect a bit of the dust, and put it in a CLEAR wine glass, you can test to see if it's calcium carbonate (one of the most common causes) by adding a bit of white vinegar. It it bubbles, it's CaCO3. If it doesn't, cover it with Saran wrap (the acid in vinegar will escape otherwise) and leave it overnight. If it dissolves, it's CaCO3.

However, it may just be paint failure.

+ It's much easier to answer your questions, when we have the details about your pool in one place. We often 'waste' the first few posts back and forth collecting information. So, please complete our new Pool Chart form -- it takes about 30 seconds, but will save much more than that.[INDENT]Pool Chart Entry Form
Pool Chart Results[/INDENT
When you complete the form, be sure to include the EXACT product brand and name of the paint used.