I tried one bottle of this or a similar product. The instructions said two applications may be necessary, so maybe I shoud try another bottle.Put some teflon tape on them mine didn't have or neighbors.. my friend used this in Florida 2 yrs it worked just follow instructions carefully or your changing sand..clogged his.
http://www.ebay.ca/itm/Marlig-Fix-A...619486?hash=item19df6c9c5e:g:8RIAAOSwGvhT751B
I have a sand filter, set the valve on recirculate, opened the main drain and shut off the skimmers after pouring the bottle in the farthest skimmer. After a day I put the filter on filter and opened the skimmers.
The directions can get confusing, and I am not 100% sure I did them properly.