Pink Slime and Swimming Pools

Jan 16, 2019 | Pool Advice

Pink Slime In Swimming Pools

If you have no idea what we’re talking about when we mention ‘pink slime’ then you are lucky. You have probably seen it, perhaps didn’t notice it and more than likely don’t have any of it in your swimming pool or spa. Pink slime is the pink or sometimes orange slimy stuff that forms around your bathroom or kitchen fittings if not regularly cleaned, and it can also affect swimming pools and spas.

Pink slime is a type of bacteria called Methylobacterium

It is non-pathogenic which means it is not harmful to humans. The bacteria form a slimy coating which provides an unusual level of protection against chlorine and bromine. They are naturally occurring and prevalent across a wide range of media (biological and environmental). They have a tendency to remain a contaminant even after treatment.

The bacterium has a natural affinity for the matrix that exists on the surface of PVC plastics; it will attach itself to and inside of the matrix, allowing it to re-contaminate long after it appears that it has been destroyed (includes pool toys, floats, ladders, steps, fountains, automatic pool cleaner parts, skimmer baskets, weirs, directional fittings, garden hoses, etc.) A small quantity in any source (e.g. tap water or plastic) can lead to quick re-establishment of the problem.

Treating pink slime in swimming pools

Treat pink slime as soon as you notice it. The longer it is left the harder it is to eradicate it.

  1. Physically remove all the pink slime you can see. Check-in and around the skimmer box, return jets, in shady areas of the pool and behind ladders etc.
  2. Check the pH of the pool water and adjust to 7.4 if necessary.
  3. Shock dose the pool with at least three to four times the recommended shock dose of chlorine for your pool volume. This may seem excessive, but if you only use a standard dose of chlorine shock you will not kill the slime. Use Cal Chlor (500 grams per 10,000 litres) or Burn Out Extreme or Power Chlor (200 grams per 10,000 litres).
  4. Run the system for 24 hours until a stable high sanitiser level is reached.
  5. Continue running the filter system and cleaning your pool using a brush and manual vacuum.
  6. Test your water – bring a sample into the store so we can advise you on how to rebalance your pool.
  7. Chemically treat the filter media with Filter Brite or Liquid Filter Brite to remove the bacteria from the filter.

Prevention of pink slime

The pink slime bacterium particularly likes areas of slow-moving water, low sunlight, and warm water. If you have any areas like this in your pool, regularly scrub the area and occasionally add a shock dose of chlorine to this area of the pool.

Bubble or solar covers are ideal places for pink slime to take hold. It’s a good idea to clean the cover annually to ensure no slime is hiding here.

If using a garden hose to refill the pool, always turn the hose on and discard the first water that comes out before putting the hose in the pool.

Regular oxidising (shock dosing) of the pool will help prevent pink slime. In summer or when the pool is heated you should shock the pool once a week.

Rain and bore water can introduce the bacterium into the pool. There is nothing you can do about this!

If you have had a problem with pink slime in your swimming pool, we recommend using Optimiser in your pool. It will decrease the likelihood of the bacterium recurring and as a bonus, it makes your water feel nicer and really sparkle!

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