I have a neighbor two doors down with a traditional chlorine pool. His home/pool was vacant (economy!) and with out maintenance for about one year. he bought the home last year about this time and I helped him clean the pool and establish proper pool chemistry over the summer. He uses tablets to chlorinate his pool. In the winter he has not put any tabs in the chlorinator tube since in cold temps you don't need to introduce chlorine. He has a DE filter that I helped him replace the guts last summer because of all the holes in the grids.
Our water has been in the 30's for months. He has had to keep water flowing to the spa and pool simultaneously during the winter months to keep pipes from freezing. Starting in the fall when he started having the spa spill over often we started seeing a lot of foam. I thought it might be some chemicals in the pipes going to the spa and would eventually clear. Strangely though all winter when water flows into the spa it produces a pretty steady foam. I think he has some minor leaks in and round his pump and filter that could be introducing air into his lines but this foam is unlike anything I have seen. At times you can scoop it out in piles with the net. It looked like laundry detergent foam in the fall but has gotten better over time. Now, when you shut the pump off for about 10 minutes the foam will clear and the water looks pretty clear. Leslie's is telling him to pour in some other chemical but I think he tried one of their solutions in the fall that did not produce any positive results.
any ideas on what is causing the foam? Could dormant pipes to the spa for one year (no water movement) have some sort of scaling that is taking a long time to complete flush out? Could this be just because of the air leaks at his pump since the foam clears in a few minutes after stoping the pump? this problem has definitely gotten better but is still not perfect and I wanted some advice before pouring in something Leslie's recommends again.