DIY swimming pools

Sand Filtration Systems

installation and maintenance suggestions

ADVICE REGARDING INSTALLATION AND MAINTENANCE OF SAND FILTRATION SYSTEMS

POSITION

Filter system must sit on a firm, level base, eg. paving stones. Protect from long grass, standing water etc. Install away from pool so it can't be used as steps by children. Electric connections must be via isolator and RCD, & in accordance with current electrical safety regulations.

BASIC LAYOUT

Water is taken from the skimmer and then goes into the horizontal inlet port of the pump. From the top of the pump it carries on into the filter. Connect to the multiport valve of the filter, via the port normally marked "pump". Come out of the "pool" port of the multiport valve. If you have a heater this should go next. Then back into the pool via the inlet nozzle or nozzles.

FILLING TANK WITH SAND

Remove lid. Place a clean plastic bag over the exposed end of the central pipe and secure with a rubber band. This will prevent sand entering lower under-drain when filling. Put water in to a depth of about 1ft, and then pour sand into tank, distributing evenly, until a few inches below top of central pipe. Now remove protective plastic bag, and fill as high as possible with water, then replace top securely.

PLUMBING INTO PUMP AND POOL

All electric connections must be made by a qualified electrician, and protected by an RCD circuit breaker. If the pump is installed closer to the pool than 10' then electrical safety regulations require that it is disconnected when people are using the pool. Screw down the lid of the pump strainer, making sure the 'o'-ring is seated properly. HAND TIGHTEN ONLY. NEVER RUN THE PUMP, EVEN FOR SHORT PERIODS, WITHOUT THE STRAINER FILLED WITH WATER. The pump seal is water lubricated, and will fail if run dry.

Prepare two long sections of the hose provided, and one short length. Only cut the hose at the cuffs moulded in at 3' intervals. For water tight connections we recommend that you heat the cuff in hot water, and tighten the jubilee clip while it is still warm. Hose-tails are provided and these should be screwed in firmly using PTFE tape or silicone sealant, but not over tightened. One long hose goes from the base of the skimmer unit into the strainer pot of the pump. The short hose connects the discharge at the top of the pump to the filter inlet, usually marked "pump". The second long hose goes from the outlet of the filter, usually marked "pool", to the return inlet fitting. The third filter connection is for dirty water, back-washed from the pool. The hose provided for vacuuming the pool may also be used for back-washing, or an optional backwash hose may be purchased for this purpose.

OPERATING YOUR FILTRATION SYSTEM

Make sure that the water level stays at least half way up the skimmer, and the pump strainer is completely flooded with water. On first use, press down the multiport valve handle and rotate to the "backwash" position. NEVER OPERATE THE MULTIPORT VALVE WITHOUT MAKING SURE PUMP IS OFF FIRST. Backwash for 4-5 minutes, to get rid of fine particles left in the sand. Stop pump. Set the multiport valve to "waste" or "rinse" and pump for about 10 seconds to flush out hose. Stop pump, set to "filter" position, start pump. Note the reading on the pressure gauge - your "clean filter start-up pressure", used to decide when the filter needs cleaning. A newly filled pool may require filtering for about 24 hours, but routine filtration should only need about 8 hours a day.

As dirt accumulates water flow diminishes. Clean the filter by back-washing when the pressure gauge reads 5 to 7psi over initial start up pressure, or every two weeks if sooner. This reverses water flow, lifting dirt off the top of the sand. Follow the procedure outlined above for first use, and continue for 4-5 minutes or until the water coming out loses most of its cloudiness, whichever is longer. Turn off pump before operating valve, and "rinse" out water left in hoses for a few seconds, to prevent a "cloudy puff" of dirty water returning to the pool.

ROUTINE CARE AND MAINTENANCE

Test the water regularly and maintain a chlorine level of at least 1.5 parts per million. Never add chlorine granules or tablets directly to the water as this can bleach the liner. Dissolve stabilised chlorine granules in a bucket first, and mix thoroughly. If you use chlorine tablets put them in a proper dispenser; concentrated chlorine can damage the skimmer etc. If the pool water does "go off" if left without enough chlorine for more than a day or so, "shock dosing" may be needed to increase the chlorine to 5 - 10ppm. For rapid "shocking" liquid chlorine or special "shock chlorine" granules can be used. Extra care is needed with the latter.
ON NO ACCOUNT MUST SHOCK CHLORINE COME INTO CONTACT WITH UNDILUTED STABILISED CHLORINE GRANULES OR TABLETS. AN EXPLOSIVE MIXTURE CAN RESULT ! Also "shock" granules leave a slight residue, and should  be mixed with warm water and added via the skimmer with the pump running, to trap this in the filter straight away.

Test the pH of the water every couple of weeks. If pH falls below about 7.2 the water acts like acid, and can attack even galvanised and stainless steel; use pH plus "pool alkali" without delay. The ideal pH is about 7.4. A higher pH is not so serious, but does reduce chlorine effectiveness, and can cause scale; use pH minus "pool acid". For greater convenience an algaecide is recommended. A clarifier is also useful after "shock" dosing. We would be happy to advise you and to supply all the necessary chemicals etc. Please do not hesitate to ask!

Leaves etc. are trapped by the skimmer basket and pump strainer. To empty the strainer, it is necessary to prevent water siphoning out of the pool when you remove the lid! Stop the pump and set filter to "backwash" to close off the return line. Remove the skimmer lid and basket, and plug the hole in the bottom with a bung or cloth. Don't forget to remove this when finished! Unscrew the strainer lid anti-clockwise, empty strainer and replace. Hand-tighten only! Set valve to "filter" and make sure strainer is flooded again before starting pump.

VACUUMING YOUR POOL

Use the skimmer lid upside-down to close the skimmer, and connect the vacuum hose to the vacuum point inside the pool, or use the separate vacuum plate if provided, with a hole at the top for the hose.  Hold the hose against the water inlet, to drive out air, then attach to the skimmer as described above so that water is sucked out through the vacuum head at the other end. Try not to allow the vacuum head to draw in air. If the water is very dirty you can vacuum to "waste", by-passing the filter.

WINTERISING

Lower the water to a foot or so below the skimmer by siphoning with the vacuum hose or a garden hose. Immerse it completely, block the end, and lower quickly to the ground. (On pools with low fittings you need to use the plugs provided to block the holes). Completely drain the pump, filter and hoses to prevent freezing damage, and remove all their drainage plugs - there are usually two on the pump. Ideally the pump should be stored indoors. Freezing damage to the filtration system is not covered by the warranty. We recommend you purchase a proper winter/debris cover, to keep out light which promotes algae growth, and to keep the pool clean. Do not leave the solar cover on - it will be destroyed if the water freezes.

We want you to have the maximum enjoyment from your new pool. You are always welcome to call us for help and advice, and for fresh supplies of chemicals, covers and accessories.

Mike Winbourne ( B.Sc. Chem. Eng., M.I.S.P.E. )