Sanding a Pool

[skingery]

I have had my pool about 12 years and I have never changed the water. Over time the pool has acquired many "brown spots". I have been told to drain my pool and sand it down. I am wondering if I can use an orbital sander and what grit sand paper?

My pool is a salt water pool, about 13000 gallons, a cleaner (I don't remember which type).

Any help would be appreciated.

[PoolDoc]

I doubt standard sand paper is what is used.

I've never sanded plaster in a pool, but I have used a diamond abrasive disc to remove paint from a pool. I used a grinder like this: Bosch 1994-6 9-Inch Large Angle Grinder (http://www.amazon.com/exec/obidos/ASIN/B0020ML6CC/scouscho-20/)
with pads like these:
http://www.tedpella.com/Material-Sciences_html/Grinding_Discs_and_Films.htm#_814_10
http://www.rockstardiamond.com/polishing-tools/rockstar-flexible-diamond-sanding-discs/?gclid=CNPFyd3EwL8CFRJk7Aod-gcAcQ

You'll need to see what's required to attach those pads to that grinder. Be aware that sanding an entire pool, even with a 9" grinder and diamond disks, is a slow process.

[skingery]

Thx PoolDoc,
I starting sanding the pool today and it is working every well but slow. I can see a noticeable change in color and even my wife likes it. It is a very slow process. I tried a regular disc sander with 180 grit sandpaper so I would not gouge the walls and it did not work very well. It have been all hand sanding. I am using a medium course foam block I got at the local hardware store. If anyone else has some advise, I would love to hear it.
Thx

[PoolDoc]

Hand sanding an entire concrete pool?

Well, I guess if you spend an hour a day, you can count it as your daily work out. But how long is it going to take?

[skingery]

Great question. I used my orbital sander today but I went with 100 grit and it is working well but also very slow. I am having a hard time deciding how much to sand. Using a sanding block, I can see a noticeable difference. With the orbital, I have a brighter white. I think the brighter white is what I want but I am unsure.

Any advice?

[PoolDoc]

Other than to get a diamond pad? No.

Good luck.