I did a quick search and found the tanks. I guess it might depend on the model, but here's a link to some hayward filter parts. The tank is availible, but it's almost as much as a new unit.

http://www.surfsidepoolcompany.com/c...ment_Parts/132

Google is your friend!

Also, as far as repair, you might have better luck repairing from the inside, but I'm not sure as I have never tried it.