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.
Thanks,

Gunite or vinyl? Whats the calcium levels? Sometimes low calcium will cause foaming.

Gunite. I have not seen any #s since the fall. But I don't see scaling and when we were at the end of the summer the calcium was right on. Again it only foams when water comes from the spa spillover. If you keep it on pool only I see no foam. But when it comes from the jets in the spa it foams and then pours the foam into the pool....

It's kind of hard to know where to start really unless we can see the test results. I was thinking about calcium hardness being an issue as well.

Some algaecides can create huge amounts of foam.

I'm thinking that what he put in there in the fall was an algaecide but I will check and see if he has his receipt to know what he bought. I will also get some test results when it is warmer and I can go over to his house for an hour or two to help him. We had a heck of a time keeping his pool from freezing up this winter.

It could be calcium hardness, or algaecide, or sometimes phosphates. You always want to make sure you put in a very good algaecide. When it comes to the pipes, it is always good to use a product called Spa Purge before you drain it. This will clean out all of the muck in the pipes. What product did Leslies recommend? Out the ones that our store sells, (Ive worked at Leslies a long time) you could either go with spa perfect, which has to be added weekly, and is really good enzyme that helps keep the water clean as well as pipes. But if youre foam is that severe get spa anti foam. It is a temporary fix, no doubt, but the second you spray some in there, the foam will vanish.

AS a simple, very economical approach, I would bring the chlorine up to a pretty high level for a week or so. I'll bet the foaming will go away.

Even in the cold water temp weather you would bring it up? Like with shock and then heavy on the tabs by putting them in the baskets and fill the tube wide open? How high... like 10?

Don't use tabs. You can use regular bleach, as it will add no additional chemicals into the water. If you can get a CYA reading on the pool, you can determine a target 'shock' level based on the Chlorine/CYA chart or the pool calculator. Treat it as standard shocking.

I'm surprised nobody has asked for water chemistry results. If he's chlorinating the pool with tablets, then he's obviously adding CYA at the same time. What are his current FC, CC and CYA levels? I would suspect he has some contaminate in the water that isn't effectively being broken down by the FC due to high CYA levels.

EDIT: sure enough, took to long to post.

What is your CYA? If you haven't done the test in a while, take you pool water sample inside and let it warm up before performing the test.

Then, I would suggest bringing the FC up to about 50% of the shock value indicated in the CYA/FC relationship chart.

The precise value (50% of shock level) is not as important as much as just getting enough chlorine in the pool to start consuming whatever is causing the foaming.

Probably a couple of days holding the FC at that level will be required. Keeping holding FC at a constant level until the foaming stops.

EDIT: bringing FC up to shock value as suggested above is fine, too. Will likely speed up the process and only use a little more FC.

Baskets? Do you mean skimmers? We advise folks to never put tabs in the skimmers....just an FYI.

I will try to do this over the weekend if I can make some time to work with him and test his water. I doubt he has tested it since the fall. I thought the chlorine was not present in pools in the winter, maybe I screwed him up by telling him not to keep tabs in his auto feeding tube. I don't test my water in the winter.... should I? I don't add salt either since my SWG doesn't operate at cold temps. Once I get some time to help test I will post the #s here and then would appreciate suggestions on what to do to help the foaming stop. My guess is CYA is gone but we'll see. Thanks,

If a pool is not winterized, it's necessary to test periodically to maintain the min FC level - during the winter the chlorine demand will be greatly reduced, but not eliminated. Some test perhaps monthly, once they determine how long they can go between chlorine additions, perhaps by testing/adding chlorine more frequently and then cutting back to monthly.