Solar Pool Covers

In response to the recent water restrictions we have had a large number of enquiries regarding solar pool blankets. There are a number of issues both for and against solar covers and many of these have not been adequately raised.

The following table shows the average predicted temperatures of water in an open swimming pool in Sydney exposed to full sunshine and a wind velocity equal to 1/3 of the mean monthly values.
A – unheated and uncovered pool
B – covered with double layer clear plastic cover
C – uncovered and heated with solar collector

A 24.3 23.5 22.8 19.0 15.1 12.3 11.9 13.7 16.9 20.2 22.6 23.7
B 29.9 28.2 27.4 22.3 17.8 14.6 14.5 17.0 21.1 25.6 28.7 29.5
C 28.8 28.2 27.4 25.3 19.5 16.2 16.4 18.4 22.0 24.9 27.5 28.3

This table is reproduced from the report “Swimming Pool Heating By Solar Energy” by J.T. Czarnecki, CSIRO Division of Mechanical Engineering Report TR19.

As the table illustrates, like solar, solar pool covers help extend the length of your swimming season by up to 3 months a year, however the differences are only minimal and the real benefits are achieved when used in conjunction with pool heating.

Sealed Air (formerly known as Rheem) commenced production of solar pool blanket material in 1976. The specially formulated polyethylene film contains UV absorbers and quenchers together with tougheners to minimise the effects of Solar and Chemical degradation. The material is manufactured at the Sealed Air Plant at Alexandria NSW and is exclusively used byDaisy Pool Covers in the manufacture of all commercial blankets.

Owning a solar pool cover will cost you about $2.00 per week forever (or $80 to $120 per annum). The pool solar covers are limited life products and will only last between 50%-125% of their rated life. A number of grades of solar blanket are available with a life expectancy ranging from 2-3 years up to 6-8 years.

When a solar pool cover is on the pool ensure the chemical balance remains correct (never allow chlorine over 3ppm) as this can remarkably shorten the life expectancy of a cover. Running your filter during the middle of the day will help disperse the heat through the pool and protect the cover however this may require some adjusting of your chlorinator to ensure only the appropriate amount of chlorine is produced..

Solar pool covers are not recommended for pools with lots of leaves and will affect automatic pool cleaners. As most pool cleaners operate using a partially submerged hose to randomly manoeuvre around your pool they are easily affected by the floating cover which restricts movement of the hose. This will force your cleaner to only clean one area of the pool or tangle. We recommend removing cleaners when using solar covers. Leaves is another issue. As you will not have a cleaner in your pool you will still get the same amount of debris. While a lot of material will land on the cover it is not easy to remove. In most cases it will fall down the sides of the cover due to the wind or on removal of the cover. As the cover is partially submerged in water this material often ends up partially submerged and is difficult to brush or remove from the floating cover.

You will lose less water from evaporation however there are a few important pointers to consider. Water and air temperature, humidity, wind level and the wind speed at the waters surface all affect evaporation rates. In dry and/or windy conditions, the evaporation rate of the pool increases, so it becomes beneficial to use a solar pool cover during daylight hours. In warm humid conditions, however, the evaporation rate decreases and it may be more energy efficient to leave the cover off during the daytime. While we are currently going through an extended period of dry weather and low humidity, Sydney is normally a warm city with medium to high relative humidity, which is why covers have never been a necessity. In the middle of summer evaporation can cause a pool to lose up to an inch or about 1000 litres of water per week.

If you are using covers to save on heating costs then the benefits can be significant, however, in terms of filtrations and chemical costs they do not lead to major savings.

Solar pool blankets must never be left in the sun while folded, even for a few minutes. This can lead to the covers breaking down very rapidly. If the air temperature exceeds 35 degrees Celcius then the cover should be removed and placed in a protected cooler storage area. Even covers stored on a roller should be protected from these conditions.

The final issue is accessibility. Having a cover on your pool can make it less easily accessible when you want to use it. Will your kids remove the cover? In some cases we know of covers not being used because the kids would swim dangerously under them rather than removing them. If you do not purchase a roller can you, or will you, remove the cover to use the pool? What times of year will you cover the pool? Solar pool covers will heat the water considerably if used in summer, however because the pool is used heavily at this time of year, they are often removed. They can help extend the swimming season, as shown in the table above, but only if they are used for extended periods to maximise heat gain and minimise heat loss. If you use the cover early or late in the season will you remove it? These questions may sound simple and obvious but they are often the questions never asked when discussing pool covers.

Solar covers are available to suit any size or shape pool. They are made oversize to allow for shrinkage when first used.

For those with leaf problems and automatic cleaners, or those looking to cover their pool in winter to minimise maintenance, you should consider debris covers. These are a sewn mesh material that is custom fitted to your pool and attached to the surrounds through a number of tie-downs. These covers stretch across the pool above the coping and are tied to the ground. They are tensioned so they do not touch the surface of the water allowing your cleaner underneath, and they also allow leaves to be blown or broomed cleanly off the top without getting into the pool. They are however much more cumbersome and difficult to fit and remove.

Pump sucking air or filter blowing bubbles?

In a standard swimming pool setup the pump pulls the water from the pool and pushes it through the filter and then it will return to the pool or other secondary pumps might push it to a pressure cleaner or through a solar system.

The pipe from the skimmer box to your main pump is where the water gets sucked into the pump from the pool. A break in this line will cause your pool to possibly lose water when switched off but it will also suck air and blow bubbles potentially causing your pump to lose prime or your cleaner to stop.

The pipes from the pump to the filter and from the filter back to the pool contain water at pressure being pushed back into the pool. A break in any of these pipes will leak (and not suck air) and you will lose water when the filter is running. A break in the underground pipes will also leak when the filter is switched off.

Most filters will self-bleed the air out through the return jets by blowing bubbles. If air is accumulating in the filter and possibly draining the pump out when you switch it off your pump will be sucking air but you may not have enough back pressure to bleed the air. This can occur if you have an oversized filter (not a bad thing) or a new clean one so there is no dirt to build up back pressure. The primary problem is still that your pump is sucking air and rectifying this will solve both problems.

Note: Most automatic pool cleaners come with a pressure relief valve or speed control. This valve is important as it ensures your pump gets adequate water flow. If over-tightened or not used your pump may struggle to draw enough water and this will cause it to suck more air. With adjustable valves always loosen them out until the cleaner stops then slowly tighten them until the cleaner starts to move. This is where you should leave the valve. You do not need to adjust it again. If the cleaner stops it will usually mean you need to clean the filter.

Before testing always clean your filter. On sand or d.e. filters it is often better to test on recirculate as this gives you a full flow of water (if this solves the problem you need to clean your filter).

If air is your problem work your way from your pool to your pump. Check the pool cleaner hoses for breaks, try with and without the vacuum plate (use hole at bottom) which will identify a broken skimmer box, check any connections, especially rubber connectors in front of the pump for breaks. Remove, re-align and re-tighten all connections on the suction line. Check that the hair and lint basket in the pump is seated properly and that the lid is sealed with an o-ring.

Any connections in the suction line such as chemical feeders can also cause problems. The easiest way to check your pool hose is to lift it segment by segment out of the water while the cleaner and pool is operating. You will hear a hissing noise wherever there is a hole, or split.

If you have not made any improvements on your air problem you may have a broken pipe underground. If you have a major air problem then an underground break would also cause the pool to lose water. If you believe this is the cause plug the hole in the bottom of the skimmer box with anything you can find (a rag or squash ball or expansion plug etc) and leave your filter switched off. Measure the height of the water and leave the pool for a few days before re-measuring (add chlorine as per normal). If the pool does not lose water you have a broken suction line underground.

With this information a pool serviceman will be able to advise you the best way to rectify the problem.

Backwashing (cleaning) a sand or d.e. filter

Sand filters and diatomaceous earth filters need to be backwashed regularly to keep them clean.
Backwashing should be done whenever the pressure increases on the filter gauge, when the water flow decreases or cleaner stops working, or every 2-3 months. To backwash your filter simply turn the multiport valve handle (the handle on top or beside the filter with a number of options such as Filter/Rinse/Waste etc). Make sure the pump is off (never turn the valve with the pump on). Turn this handle to the backwash position . Then switch on the pump. This will wash water through the filter washing any dirt down the drain. You should be able to see this water through either a sight glass on the valve or through a clear section of pipe, otherwise watch the water pouring into the drain. When the water starts to clear, switch off the pump and turn the handle to rinse. Run the pump on rinse for approximately one minute to rinse any disturbed dirt from the filter so it does not go back into the pool. Some older filters may not have a rinse function. Backwash these until the water is clear to avoid sediment returning to the pool. Return the valve to the filter position when finished and your pool can be used as normal. Diatomaceous earth filters need to be thoroughly disassembled and cleaned every 6-12 months. If you find the pressure increases rapidly again after backwashing you may need to disassemble the filter. If you have persistent high pressure problems with a sand filter contact a pool shop for assistance.
Properly treated pool water is often better than our tap water. Water conscious pool owners may want to use this water to water lawns and gardens. This should not affect any lawns or native plants. The pH of your pool water is 7.2-7.8 so it may not be ideal for rose gardens or other gardens treated to meet certain pH soil recommendations (through the use of Lime or similiar).
Due to the dry drought conditions facing Sydney and NSW at this time we are finding pools are accumulating a lot more loose sediment and dust than normal, especially during periods of high wind. If you have an automatic cleaner you may have to backwash even more often due to these conditions. Your pool may look spotless compared to your neighbour but that will be because all the extra sediment has been collected by your cleaner and sucked up into your filter so your filter will need to be cleaned more regularly.

The following diagrams show the most common types of multiport valves.

Hayward MPV Quiptron 2000 MPV

Salt Chlorinators

Salt is actually Sodium Chloride. Salt Chlorinators work by breaking up the salt molecules and releasing the chlorine into the water. This is how they chlorinate your pool for you.

By keeping a level of salt between 0.4% and 0.7% (depending on brand) they can produce 15 – 30 grams of chlorine per hour. As a side effect the chlorinator cell will clog up with a calcium residue which needs to be cleaned regularly (fortnightly to monthly). Due to the way salt chlorinators work they also increase the pH of the pool by creating Sodium Hydroxide (a base). The means that you will need to add acid to the pool more frequently to compensate.

The best way to test your salt level is to take a sample to your local pool shop, however test strips are now available.

Cells should be cleaned vary carefully. If cleaned regularly while any calcium deposits are soft they can be simply washed under a tap. Warm water can help. If the deposits are harder you may need to soak the cell in either a 10/1 or weaker water/acid solution or a cell cleaner (an organic acid). This will help soften the deposits. Do not leave the cell in this solution for longer than necessary as this will shorten the life of your cell. A paddlepop stick or similiar wooden or plastic instrument can be carefully used to remove calcium deposits. Do not brush or scrub the cell. Chlorinator cells are plated in Titanium and Platinum, hence the cost, like Jewellery. This plating is what makes your cell produce adequate amounts of chlorine. If it wears too much the cell will go black in color and will not produce enough chlorine. You must treat your cell like jewellery when cleaning to ensure it lasts.

Self cleaning chlorinators are available but check the life expectancy of the cell and it’s replacement cost as many are worth almost double the cost of a normal cell and do not last as long due to their self cleaning process. Self cleaning chlorinators save you from maintenance of your chlorinator at a small premium. Some cells like the Watermaid Ezy-Clean are so simple to clean that a self cleaning unit is unnecessary. The new Watermaid power supply is self-cleaning as standard and it’s patented design will not reduce the life expectancy of the cell.

Make sure you have a stabiliser (isocyanuric acid) level of 50-100 in your pool. Due to the slow production rate of chlorinators on a hot day the sun can remove chlorine faster than your cell can make it. Stabiliser holds the chlorine in the water.

Some plumbing is required to install a new salt chlorinator and it might be worth letting the professionals install it correctly. Otherwise ask us for advice and we can show you how. It is essential that self cleaning chlorinators are plumbed correctly. Incorrect plumbing can impact on the self cleaning effect.

Salt chlorinators save you having to dose the pool with chlorine daily however they do still require regular maintenance. They are not cheaper than just using chlorine but they can look after your pool when life is busy.

Dosing Pumps

Dosing pumps are one of the most cost effective and simple chlorinators available. A basic dosing pump simply pumps chlorine from a drum into your plumbing when the filter is operating. Your filter will dispense this chlorine back into the pool. You can adjust the rate at which these pumps disense chlorine to adjust for different weather conditions or seasons. Some units even have a super dose button which usually doses over a litre of chlorine.
pH dosing pumps are also available to dose acid to manage your pH level.

Dosing pumps run when your filter does, so they can distribute the chlorine carefully throughout the day. This means your pool is getting chlorine when it needs it and it also means you can reduce your chlorine usage. A dosing pump can often use only 500-750ml a day. 60L drums are also available saving you from looking after the chlorine for months. Our delivery men can also fill your 60L drum rather than leaving you with new small ones and will remove the empties so you won’t even have to touch chlorine. Delivery is free in the Sydney metropolitan area.

Dosing pumps are also simple. A basic unit consists of a single squeeze tube, which is the pump, and two tubes for intake and output. It has a dial for speed adjustment and a piggy back power cord. They are reliable and very simple to repair and maintain.

For those who want the ultimate in maintenance free pools, more complex models are available. These can not only chlorinate your pool, but also maintain the pH. Some units even have digital readouts which allowing setting and monitoring of ORP (chlorine) and pH levels at any time.

Leaking Pumps

Any leaks around your pool equipment are a bad sign. A continuous leak or drip can cause corrosion and long term damage to your equipment.

The most common leaks occur from the discharge of the pump (the pipe connection on top of the pump) where the water goes from the pump into the filter. A leak here will drip down onto the motor and can cause corrosion and damage to the motor casing, surrounds, endshield and bearings.

If you have difficulty removing the lid of your pump remember to tighten all of the union connections when finished. When you are trying to open that lid the pump will often rock back and forth and this will loosen the union connections, especially the discharge. This can mean the next time the pump operates it will leak onto the motor.

The other common leak is from the pump seal and water will leak from underneath where the pump and motor sections join. This can occur due to old age or if the pump is run without water for any period of time.

Pump Checking Steps [PDF]

How to prime a pool pump!

When re-installing a pool pump it must be primed so it is full of water and ready to operate. The water flowing through the pool pump helps keep it cool so a lack of water flow can cause serious damage.

a)First reconnect the pump and both the suction (from pool) and outlet (to filter) pipes to it.
b)Cartridge filters – ensure your cartridge is clean first.
Sand filters or DE filters – turn filter multiport handle to recirculate or auxiliiary filter.
c)Remove the clear hair and lint pot lid from the front of the pump. Fill the pump as much as possible with water and replace the lid.
d)Switch on the pump. Within 30 seconds to a minute water should start pouring into the pump and you should start seeing bubbles coming out of the return jets in the pool. If the hair and lint pot on the pump is empty after this time, stop the pump and repeat steps c and d.
e)If pump remains full when switched off and starts pumping immediately when turned back on then your pump is now primed. Switch the pump off, turn the handle back to filter (sand or d/e) and then turn it back on and you are back in business.