Cleaning the Filter | Pool Maintenance

Cleaning Cartridge Filters

Cartridge filters are somewhere between DE filters and Sand-filters in terms of efficiency and the size of particle that they can remove from your pool-water

Cartridge filters pack a huge filter-surface area into a very small space. Most cartridge filters have a filter area greater than 25 m² (250 ft²) and need to be cleaned less frequently than sand-filters, reducing water-loss

Some filter elements are inexpensive to replace but they don't tend to last as long. Other filter elements can be costly but will last for several years. Largely, you get what you pay for

In general terms, Cartridge Filters need to be cleaned only once or twice a season, simply by hosing them off with a garden hose. Do not use a power-washer as the force of the high-pressure jet can easily tear holes the cartridge elements, rendering them useless

However, sometimes a cartridge can become contaminated with sun-cream, etc., and in this case it should be soaked in a filter solvent, available from any pool-shop

Should you have a cloudy, green pool, however, the filter will clog more rapidly and need to be cleaned more frequently

Tip: - When replacing an old filter cartridge element with a new one, make a note of the pressure on the tank pressure gauge and mark the gauge with a PERMANENT marker pen

This reading is the lowest it is ever going to be as the cartridge has not yet collected any dirt and therefore the water passes through the filter membrane easily

Make a similar mark at approximately 0.5 Bar or 8 pounds per square inch (psi) higher than the first mark

These 2 marks represent the upper and lower limits of the normal operating pressure for your cartridge, in pounds per square inch (psi). Make a note of these 2 figures in your Pool Logbook

Clean the cartridge when the gauge reaches the higher pressure mark and, after re-fitting it, make a note of the new start-up pressure. As the cartridge gets more use its efficiency will drop off and having the normal operating pressure data for your cartridge to hand will help you decide when the element needs cleaning again

Cleaning Instructions

Follow the manufacturer's instructions to remove the cartridge from the filter housing. If you don't have these instructions to hand you will almost find them online on the manufacturers' website. Don't you just love the Internet?

Working from top to bottom, wash accumulated dirt from the element, paying particular attention to between the pleats, with a low-pressure garden hose

As stated above, do not use a power-washer or you risk destroying the membranes

Continue cleaning until all the dirt has been removed and the water runs clear

If the filter is clogged with oils, soak it overnight in filter-cleaning fluid or, alternatively make up a mixture of washing-up liquid and water

The home-made mix will not be as efficient as the proprietary products but will still do a pretty decent job

Rinse the cartridge thoroughly to remove cleaning solution residues and loosened dirt

Acid Washing of filter elements

Acid washing should only be carried out when it is calcified (perhaps from a too-high pH of the pool-water?) and the element should first be thoroughly cleaned, as above, with a hose and a cartridge degreaser first

You can easily discover if your cartridge would benefit from an acid wash by dripping one or two drops of 5% Hydrochloric (Muriatic) Acid/water onto the pleated element

If the acid produces bubbling your cartridge would probably benefit from acid-washing

If no bubbles form your cartridge would probably not benefit; rinse the cartridge again and re-install

Cartridge Acid Washing - Instructions

Make up a solution of 5% Hydrochloric Acid and water

Wear rubber gloves and eye-protection when handling acid or other pool chemicals

Note: add the acid to the water, not the other way round

Soak the cartridge in this mixture until all bubbling ceases

Rinse the cartridge again with fresh water from a garden hose

Wash your hand immediately after handling any pool chemical

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Ken Walker - MyPoolGuru©

Cleaning DE Filters

- cleaning a DE filter is a little more complicated than simply back-washing a sand-filter or rinsing off the filter elements of a cartridge filter

Having said that, it's a job that a Pool Pro will charge good money for - and for good reason - so if you can do it yourself you can reduce the cost of maintaining your pool

There are a lot of delicate components inside a DE filter and they can be damaged by rough or inappropriate handling

Cleaning the grids of a DE filter should not be attempted unless or until you have either studied how a Pool Pro does it or have some instructions on how to do it

I feel that there is little to add to the excellent advice provided by Steve Litt of Troubleshooters.com

Read Steve's' full article here

We supply all plant and equipment featured on this website. All our work is Guaranteed; Parts and Labour

Note: - Please contact our recommended pool professionals for supply and installation of all pool-related services: -

Andalusia and the Costa del Sol - Pool Safety Spain

Nerja area - This email address is being protected from spambots. You need JavaScript enabled to view it.

*We only offer Quotations: - a fixed, agreed price that cannot, and will not, be increased. We do not give 'estimates', as an estimate offers the client no guarantee of final price

Ken Walker - MyPoolGuru©

Cleaning Sand Filters

Before I explain the procedure to clean a sand-filter - also known as Back-washing - I'll explain how they work and how to make the filter contents last a lot longer.

Unsurprisingly, sand-filters contain SAND, but it's a very special type of sand called Silex. Most sand is more or less round, as a result of being knocked about in water (visualize waves on a beach), which chips the edges off.

Silex is different - it's produced by crushing silica rock. The resulting sand has flat faces and sharp edges; not round at all.

Now imagine one flat-faced grain of sand with another one pressed closely against it, leaving a tiny gap. It is the size of these gaps that determines what size of particle the Silex can trap between the grains. When the Silex is new it will trap particles of about 15 microns or larger but, over time, it wears out and can only trap particles of 25-30 microns or larger.

Why does it wear out? As the water circulates through the filter, from the top to the bottom, suspended particles are trapped between the grains of Silex: and the water is cleaned. Eventually, the filter has trapped so much debris that the pump cannot push much water through it - and it's time to back-wash.

During a back-wash (full instructions below but please keep reading) the flow of water through the filter is reversed. The pump no longer has to push water through a full filter. Now water flows strongly from the bottom of the filter to the top and out to the drains - and in doing so it 'Fuidizes' the filter media, stirring the whole filter contents and loosening the tiny trapped particles. The smaller, light trapped particles are flushed away, leaving the heavier Silex grains in the filter ready for the next filtration cycle.

During Fluidization the grains of Silex are violently bashed together just like on that beach you were kind enough to visualize above - resulting in tiny bits being broken off. These microscopic particles are much too small to be caught in any sand-filer, and too much small to sink to the bottom of the pool, so they circulate endlessly through the entire pool, including the filter.

As the Silex particles pass through the filter they erode the sharp edges of the Silex and produce even more micro-particles, accelerating wear-and-tear and bringing forward the time when the Silex must be replaced.

However, there is one, almost miraculous, product that will catch the tiniest particles of Silex - Jolly Gel. It is placed in the pump-basket (the pump pre-filter) and dissolves over a couple of days. It has an affinity for filter media so it stays in the filter and does not get out into the pool.

Jolly Gel places a porous, glutinous membrane over the filter media down to about 6 inches (150 mm), filling-in the tiny gaps between the grains. The membrane is 'sticky' at the microscopic level and catches the tiniest particles, down to 2-3 microns, on contact. It is so efficient at doing this that a cloudy pool can be brought to the point of 'invisibility' in 24 hours.

The membrane is flushed away to the drains on the next back-wash, leaving a perfectly clean pool and a perfectly clean filter. As there is now nothing left in the pool for the filter to trap it takes a long time before the filter needs to be back-washed again; typically every 4 - 6 weeks instead of weekly. This saves an average approx. 40m³ (10,500 US gallons) of water each year in a 50m³ (13,200 US gallon) pool, and also saves the chemicals and HEAT that are lost by back-washing, but the biggest saving is in the extra life, at least DOUBLE, of the filter media and anything else that is eroded - like the Tantalum Oxide coating on the expensive plates of a salt-water chlorinator or the tips of a pH probe.

TIP: - The micro-particles of Silex are far too small to be seen with the naked eye but try looking at night with the pool lights on. If you see a fan of light in the water you have the problem outlined above. But now you know the cure!

See the panel on the right to buy Jolly Gel - you'll be glad you did!

BACK-WASHING THE FILTER

- to clean (back-wash) the sand filter

Turn the pump switch to ‘off’

Set the Multi-port or Rotary valve to ‘Back-wash’

Open the ‘Bottom Drain’ and ‘Waste’ valves; close the ‘Skimmer’ and ‘Vacuum’ valves

Turn the pump on and observe the wastewater colour in the tell-tale on the Rotary valve

When the water runs clear, stop the pump at the switch

Set the Rotary valve to ‘Rinse’

Start the pump and run for 20-30 seconds

Set everything to ‘Filtration’ - detailed below

Pump room - Filtering - 'Normal Running' Positions

Rotary Valve to ‘Filter’

‘Skimmer’ and ‘Jets’ Valves fully open

Bottom Drain Valve half open

‘Vacuum’ and ‘Waste’ Valves closed

Timer running and set for 4 hours in every 12 hours

Always have the pump/filter running when the pool is in use

We supply all plant and equipment featured on this website. All our work is Guaranteed; Parts and Labour

Note: - Please contact our recommended pool professionals for supply and installation of all pool-related services: -

Andalusia and the Costa del Sol - Pool Safety Spain

Nerja area - This email address is being protected from spambots. You need JavaScript enabled to view it.

*We only offer Quotations: - a fixed, agreed price that cannot, and will not, be increased. We do not give 'estimates', as an estimate offers the client no guarantee of final price