Monthly Archives: September 2009
Here’s a question that just came up today. One of our dealer’s reported that a homeowner’s pool turned green with algae in August, so he added algaecide. All the algae turned brown and fell to the floor, like it is supposed to, but when he vacuumed it up he had brown stains left in certain areas. The stains are the same light brown color as the dead algae but appear to be glued to the liner and are rough to the touch. He tried scrubbing and rubbing, but nothing would remove these stains. As soon as I saw the photo (see below) it confirmed what I suspected. Pool Goo or Pool Tar. I recognized it because the same thing happened to my dad’s pool a few years ago.
The good news is that “pool tar” is not a big problem. It will resolve itself given time. As you can read below in a report from a vinyl manufacturer, plasticizer has come out of the vinyl. It is a sticky, gooey substance that attracts whatever dirt is in the pool and over time, under normal operation, the material is re-absorbed into the vinyl and the stains appear to vanish. I think it may have taken six months to clear up on my dad’s liner, but it does go away. I usually hear about this showing up when the pool is opened in the spring. That makes a lot of sense in that most winterizing kits contain algaecide, and that combined with a high chlorine level seems to create the problem. Do not try to remove the stain aggressively; this may permanently damage the liner. Just give it time.
* The following article comes from the Technical Manual of Canadian General-Tower Limited, a manufacturer of the vinyl sheet used to make pool liners.
Sticky Substances on Vinyl Liner commonly referred to as “Pool Tar” or “Pool Goo”
The consensus in the pool industry is that there are several sources of sticky substances, often referred to as “pool goo” or “pool tar” that adhere to and coat portions of the vinyl pool liner.
Some of these sources are:
1. Algaecide-humate or Quat-humate formed from the interaction of quaternary ammonum compound used in some algaecides and decaying organic material such as leaves, grass, insects, etc.
2. Interaction of quat algaecides with other substances. Even chlorine can interact with quats to form sticky material if both chlorine and algaecide exceed the recommended dosage levels. Quats can easily come in contact with high chlorine levels in automatic chlorinators, resulting in a gummy material gradually being fed into the pool, where it eventually precipitates on the liner. Many quat containers are labelled with cautionary notes warning against mixing with pool water having high chlorine concentrations.
3. Chlorinator goo can form when organic material from cosmetics, tanning lotions, etc. are oxidized by high chlorine concentrations resulting in a beige, waxy material.
4. A light coating of vinyl plasticizer may exude to the surface of newly installed liners during the first idle period of winterization. This material is clear and only turns dark if contaminated with dirt. It is attributed to lack of circulation, since it has never been observed in a pool that has been circulated over the winter. It will almost always re-absorb in two or three weeks if the water is allowed to warm up and is circulated and shocked with chlorine every couple of days. The problem is not known to occur more than once in the life of a liner and always the first time the pool is re-opened after winterization.
5. Pool scum is a ring that forms aroudn the pool at the water line and is made up of soil, contaminants from suntan lotion, environmental pollution, and organic materials from bather load, etc.
The following procedure has been recommended by experts in the pool industry as being effective in eliminating “pool goo” or “pool tar” problems.
1. Stop using quaternary algaecides.
2. Reduce and maintain pH at 7.0 – 7.2.
3. Superchlorinate every other day to 6.0 – 8.0 ppm.
4. Use heater to speed up warming of water, if available.
5. Continue to circulate water and monitor pressure on filter.
6. Backwash filter as often as required.