We are reminded of the terrible floods that struck New Zealand. Here is some advice from David Lloyd (renowned pool chemical expert, founder of International Quadratics) on how to clean up swimming pools after flooding.
Swimming pools can be affected by storms, cyclones, and flooding in many ways, including the following:
* The pool was contaminated with dirt and other debris
* Algae formation by diluting the chlorine
* Diluting the salt and minerals in the water
Here are some quick tips to help you deal with the situation.
Step 1 Clean the pool of dirt, debris and leaves. Clear the pool of large debris, such as branches and leaves. A heavy duty floc may also be needed if the water is very dirty, such as when soil has been pumped into the pool. Follow the instructions on the label of the floc and vacuum the pool. For important information on how to keep the pH high so that flocs can function properly, see below.
Step 2 Re-balance pool water, including adding salt and minerals.
required.
Step 3. Dose the pool.
Step 4 Use the phosphate remover as directed to get rid of unwanted phosphates.
Step 5 Use a clarifier if you have cloudy water.
Step 6. Apply a winteriser treatment, maintenance algaecide.
Flocculants, coagulants
Perhaps this is a good time to refresh your knowledge on flocculants, and how they work.
Although the terms “flocculants” and “coagulants are often used interchangeably, clearing dirty/cloudy pools involves two stages.
Fine particles suspended in water cause turbidity or cloudiness. These particles are usually smaller than 2 microns in size and will pass through the filter system. These particles are low in density and will be suspended in water. The majority of particles are negatively charged and repel one another.
To remove these particles, it is necessary to first add a flocculent (positively-charged) to the solution. This will coagulate the small particles into larger “flocs”, neutralizing the negative charge and allowing them to combine to form a floc.
Light flocs are flocs that remain suspended in water. They may rise to the surface and then settle on the filter bed. Lighter flocs may be formed by organic matter and algae.
Clay, dirt, and dust, which are denser, will form more flocs, which will sink to the bottom of the pool. This sedimentation should then be vacuumed up. The type of flocculent used can also determine if there is a heavy or light floc. Aluminium-based flocs, such as Alum or poly aluminium chloride (PAC), will form a thick floc that settles to the bottom. Cationic electrolytes and other natural flocs, however will form lighter flocs which are more easily caught by the filter.
If the pool is extremely dirty, such as after severe storms or cyclones, then we recommend using a heavy floc like liquid PAC or powdered/granular alum.
The importance of pH
Important to remember that aluminium flocs work only at high pH. You must first increase the pH to at least 8.8 when using Alum, or 7.8 if using a liquid-PAC based product.
The pH of alum is low and it will instantly reduce the pH of water after being added.
A common practice with Alum is to raise pH to 8+ by using Soda Ash, then add 2kg to 4kg of sodium bicarb (buffer), while adding the Alum. This will increase the Total Alkalinity and compensate for any pH drop.
The pH of a PAC-based product should be at least 7.8. The effect of Alum on the pH of water is much less than the one from Alum, so any further reduction of pH is often unnecessary. Alum typically contains 8 percent Al2O3 as the active floc, while PAC can contain 23 percent Al2O3 which is three times more.
Floccing points
Several important things to remember when flocking pool are:
* Live algae can be difficult to floc. Superchlorinate with liquid chlorine if there is evidence of algae. This will also help to raise the pH.
*If Phosphates are present, the floc could be partially used up floccing them and slow down the process of clearing out the pool.
* Salt and high TDS levels can also slow down or prevent flocculation. This can be compensated for by using a floc with an integrated accelerator.
* Many flocs will not work with cartridge filters or DE. DE filters should be used on’recirculation” or ‘Bypass’.
* Do not use a floc in cartridge filters unless there is a valve that allows water to go to waste. In this case, you will need to first take out the cartridge and then vacuum it to waste. A light clarifier can be used if a waste valve is not installed. However, the cartridge should always be cleaned to prevent pressure buildup.
A final tip: After vacuuming and rebalancing your pool water, place a clarifier inside the skimmer basket. This will really polish it and make it crystal clear.
Avoid emptying swimming pools
No matter how bad the water is after a storm or flood, it is important to remember that the ground conditions surrounding the foundations of your pool will be very wet. It is best to not drain pools until the ground conditions are dry to at least the pool’s depth. Otherwise, the whole shell (fibreglass and concrete) could “pop” due to the change in Hydrostatic Pressures.
Most swimming pools and spas can be restored to normal after flooding, storms or fire, except for those that are severely damaged. It is best to leave this job to professionals. Pool owners should not drain their pool.
Safety issues, including electrical and other.
Additionally, Poolwerx CEO Nic Brill warned that electrical problems, as well as water contamination and residual debris, insect infestation, and pool surface staining, pose serious safety and health risks.
He said that floods leave behind a trail of destruction for homeowners and families. As we tackle this massive clean-up job, safety and health will be our number one priority.
First, ensure that equipment like the pool pump or chlorinator is safe to use.
“If your pool equipment was submerged completely or partially, make sure a licensed electrician inspects the entire installation before you arrange the restoration of electricity to the property. When cleaning up, water contamination is another risk.
He says, “It’s quite a clean-up, so pool owners need to remember to wear gloves, masks, and goggles and to wash their hands with disinfectant afterward to prevent contamination.”
Flood waters can also pose a risk to submerged debris and flood waters often carry unwanted guests such as snakes or trapped wildlife. Flooded pools could also become a breeding ground for mosquitoes, toads and other insects.
Floods can also cause flooding, which can lead to the creation of green pools. A green pool can increase your risk of getting a gastro-infection. According to a Griffith University study, green pools can be a breeding ground for Legionella and Cryptosporidium parasites. These parasites can cause gastroenteritis and ear infections, and even death in extreme cases.
Do you drain it or not? It all depends on the location of the pool and the soil on which it is situated. However, it is important to seek expert advice before draining the pool. The pool shell could pop out of the ground, creating another safety concern and costly repair. It is possible to treat most flood-impacted pools water. However, it may take longer.
Finally, a flood can permanently stain your pool’s surface.
“The pool’s surface could be permanently stained by the sewage-contaminated water if it’s not cleaned up promptly. This could lead to a costly repair.”
SPLASH! Magazine published the article Cleaning swimming pools after floods and storms. Magazine.
