Pool Tips

What causes cracks in swimming pools? Cracks can be caused by a number of issues, we’ll take a look at a few in this blog. Once a swimming pool is cracked, seek advice and remedial services from a reputable swimming pool builder that belongs to the professional association in South Africa, namely, the National Spa and Pool Institute (NSPI).

One of the fundamentals when building a swimming pool is to make sure the ground you’re building the pool into is suitable. Very often, pool builders who belong to the NSPI in South Africa have had enough experience to [read more] know whether the soil is going to cause a problem down the line or not. The second part to building a good, solid swimming pool is to make sure the specifications (or minimum specifications) are adhered to. For example, the NSPI in South Africa insist on a certain size and type of reinforcing steel depending on the size of the pool and the soil conditions. Sometimes the appointed engineer may request the builder to underpin the pool with piles to prevent the shell from settling or moving and cracking.

BLUPOOL, a reputable swimming pool construction company in Durban North, recently had the task of rehabilitating an 8m x 4m swimming pool which had cracked in several places. On closer inspection of the pool, we discovered that the pool did not have a ring beam around the top of the shell, and the shell had also settled. The movement caused long downward cracks in the swimming pool, and the pool ‘leaked like a sieve’. There were also places in the surrounding paving that the bricks had sunk into hollows in the soil.

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Our first activity was to drain the pool and uplift the paving around the swimming pool. We then opened up spaces next to the shell which would enable us to build reinforced concrete ‘pillars’ to which we could strap the shell. We then stitched the cracks in the pool with steel ‘staples’ and strong epoxy. Finally we cast a steel reinforced ring beam around the pool which would hold the pool shell in place. 

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Once we were happy that the pool was stable and strong enough to hold water, we re-tiled the scum line and plastered the pool with a good quality Marbelite (marble plaster mix). The preparation of the the pool surface before plastering is essential for longevity of the marble plaster. If done correctly, and with properly balanced water after the pool is filled, black algae, rough patches and pitting will not be in issue for many years to come. A good, well rounded pool company that is proficient in all areas of swimming pools (building new swimming pools, renovating swimming pools, maintaining water balance in swimming pools) will always balance the pool water after re-filling the pool and before handing it back over to the pool owner.

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Avoid the temptation of getting as many quotes as possible and going for the cheapest pool contractor. Nine times out of 10 this will backfire and end up costing more money a few years down the line. Unscrupulous pool contractors that undercut reputable companies will take short cuts without the pool owner even knowing. These short cuts will manifest into problems down the line, and the pool contractor can often not be found.

Do your homework, get a good pool contractor not a cheap one, and finally, happy swimming!

The suction pipe (the pipe that joins the swimming pool weir to the pump) has to be airtight in order to be effective. If there is a break in the pipe, your Kreepy won’t work. One way to tell if you are getting air into your swimming pool system is to check if there are air bubbles blowing into your pool through the aim-flow jets (nozzles).

Water Jet bubbles

The presence of air bubbles does not always mean that air is getting sucked in through the underground pipe. It can also be getting in through a hairline crack in the pump lid, or the weir casing itself could be cracked. Sometimes the pump lid’s O-ring gets pinched and this can also cause air to get into the system.

Nine times out of ten, when there is a leak on the suction pipe, the swimming pool loses water when the pump is off. The procedure to test if this is happening is as follows:

  • Fill the pool up to a certain spot, let the water calm down and the make a mark on the weir (with a pencil, pen or a piece of tape.)
  • Disconnect the Kreepy and remove the vacuum lid from the weir to prevent a whirlpool from forming.
  • Bypass (override) the timer so that the pump does not switch off during this part of the test.
  • Run the pump continuously for 24 hours (from 7am to 7am the following day for example), without allowing it to switch off.
  • If the water level has dropped, make a new mark on the weir.
  • Now switch the pump off for 24 hours. Try not to have anyone swim during these tests as this could affect the results.
  • After the pump has been off for 24 hours, if the water level has dropped, make a new mark on the weir.

If the water level in the pool drops quicker when the pump is off than when it’s on, then it is possible that you have a leak in the suction pipe. It’s best to get it replaced as soon as possible. Running your pump with a broken suction pipe can damage the pump. If this happens, air will still be entering the pool system after you’ve replaced the pipe, but now it’ll be coming in through the damaged shaft seal in the pump.

If the water level does not drop during either of these tests, then air could be getting into the swimming pool system through the pump body, the pump shaft seal or sometimes the pump lid. It could still be the case that there is an air leak on the suction pipe, and that the crack in the pipe just closes when the pump is off, effectively preventing water loss.

Another way to test if the suction pipe is leaking is to run a temporary pipe above the ground from the pump to the pool. Plug the Kreepy into the pipe and see if it works. If it does, then voila – you have the answer: replace the suction pipe.

If you’re in the Durban area and you’re not sure how all this works or you really don’t have time to figure out why your Kreepy isn’t doing its job, leave it to us! Feel free to give Blupool a call on 031 569 2092 or +27 (82) 6986036. We are registered members of the National Spa & Pool Institute of South Africa


Don’t you hate it when you get home from work and your pool is in a mess because your Kreepy has stopped working? By Kreepy, we mean any automatic pool cleaner, or APC. Some call it a Baracuda or a Zodiac, but Kreepy is the generic name for an automatic pool cleaner. Interestingly enough, it’s called a Kreepy because the first ever automatic pool cleaner was a Kreepy Krauly – and it was invented by a Belgian engineer living in South Africa.

There are three main reasons a Kreepy stops working, other than the usual scenario of a leaf, stone or berry getting stuck in the Kreepy’s throat. 

  •   The filter sand gets clogged.
  •   There is a suction, air leak or pump-related problem.
  •   The Kreepy itself (or other swimming pool apparatus) is faulty.

The most common cause for a Kreepy to stop working is the sand filter being clogged. This is usually easy to diagnose, because whenever you backwash the pool filter, you’ll find that the Kreepy works like a bomb for 10 minutes, and then it gets sluggish and slows down.

Remember that your pump is pumping around 100 000 litres of water every day though your sand filter. When you do a backwash, only a couple of hundred litres of water is used to remove dirt from the sand. It’s never going to be enough to get your sand back to brand new status. When the filter is set back to normal filtration after a backwash, the dirt that wasn’t loosened sinks deeper into the filter sand. This is why we need to change our filter sand from time to time. We recommend changing this every one to five years, depending on the bather load of the pool and the soil conditions around the pool.

To make sure that clogged sand is the problem, switch the pump off and turn the multipart valve to the ‘bypass’ or ‘circulate’ position and then try running your Kreepy. If the cleaner flies around the pool like an ex-girlfriend on a broomstick for an hour without getting sluggish, then you’ve hit the nail on the head – it’s the sand that’s the problem.

If you’re not sure how to change the sand in your filter, rather get a pool company to do it – and make sure it’s a pool company registered with the National Spa and Pool Institute of South Africa. There are some risks to doing it yourself, such as the fact that the bacteria in a sand filter can make you very sick. Also, you could inadvertently damage some of the plastic fittings inside the filter tank, especially if they are brittle.

Check in again for the second part of this swimming pool blog, where we’ll talk about the possibility of a suction leak in your pool piping.


Did you get mud in your swimming pool after this recent downpour in Durban? As pool owners we spend so much time making sure our swimming pools are crystal clear and inviting to dive into. 

After staying perfectly clear during the months we don’t use our pool, the weather warms up and…viola! A flash flood. Dumping all the beautiful top soil from our garden beds into our swimming pool!

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The best thing to do when you suspect you have mud in your pool is to disconnect the APC (Automatic Pool Cleaner) or ‘Kreepy’, as some of us like to refer to all pool cleaners as. 

If the pool is overflowing then backwash the filter. Make sure you’re not touching the circuit breaker on the pool DB with both of your feet submerged in water. You could get a tingle in your arm, or you could get a lights-out situation. For good. Electricity can be a M.F. like that.

If it’s safe to do so, backwash some water out of your pool, and make sure the Automatic Pool Cleaner (Kreepy) isn’t connected to the vacuum lid in the weir. If it is connected, you’ll just be sucking mud into your filter.

So, now you have a muddy pool. Even the Labrador is turning his nose up at it. Below is my step-by-step procedure to flocculate and vacuum your own pool. I use this to train my staff on how to vacuum customers’ pools. 

Flocculation is the process by which individual particles of suspended matter in water coagulate into clot-like masses or precipitate into small lumps. Flocculation occurs as a result of a chemical reaction between the particles and another substance, usually alum powder - in the case of swimming pool treatment.

A few things to take note of:

This soil and rain water has rendered your pool water totally out of balance. You’ll need to get it checked at a competent pool shop, preferably with a water test station that can test, calcium, stabilizer, TDS (Total Dissolved Solids) and Total alkalinity. (I’m not trying to scare you with these big words, but these simple factors of your water balance will be the difference between a well behaved pool and a pool you’ll want to fill in with sand.)

Here goes: Flocculate and Vacuum a swimming pool

1. Raise the water in the pool to its highest level and clear all leaf trapping devices. 

2. Select ‘Bypass’ or ‘Circulate’ on the Multi-Port Valve

3. Add 1kg Alum Powder per 20kl of pool water. (If the pool is green, add an algaecide and chlorine to the water too.)

4. Run the pool pump and filter on bypass for two to four hours, then turn off the pump and allow the sediment to settle overnight. (Or longer if needs be).

5. Connect one end of the pool vacuum (Kreepy) hose to an 8-wheel vacuum device or a hollow brush and the other end to the vacuum lid in the weir.

6. Turn the filter Multi-port Valve to ‘Waste”

7. Turn on the pump and vacuum the sediment off the bottom of the pool. Take care not to stir up the sediment into the water as you are vacuuming. (The trick here is to be quick enough not to run out of water in the pool but slow enough not to agitate the water.) Perhaps run a hose pipe into the weir whilst doing this to ensure you have enough water to complete the task.

8. Turn off the pump and set the filter valve to the “Filter” position. Disconnect the pool vacuum.

9. Replace the water lost through vacuuming and bring the water level in the pool back to normal.

10. Backwash the pool filter.

11. Set the Multi-port valve to “Filter” for normal operation. 

NB: Balance pool water

I hope you have found this article helpful? We can offer you this service if you live in the Durban North area.