Plant Room Design and Install

We specialise in complete swimming pool plant room installations and can offer a full turnkey package starting with design through to installation and commissioning.

With over 30 years of experience in water treatment, we have worked on many successful projects designing and installing pool filtration systems following PWTAG best practice guidelines.
Many of our projects are to retrofit a new plant room into an existing site which provides challenges in regards space available and access into the site. Good design and project management are the key to our success.
As well as good design, it is important to use high quality equipment to ensure pool water is clean and safe. We work with equipment suppliers that have a proven record of quality equipment for use in swimming pools. On top of industry standard equipment, we offer a number of new innovative products that offer users additional benefits such as energy saving and improved water quality.

Filter Replacement

We supply and install industry standard replacement filters including GRP, Laminated and Split filters as well as new generation filters such as the Defender and Ceramiflo systems.

All our filters are “deep bed” and are selected to provide at least medium rate filtration.

Our comprehensive range of GRP filters are manufactured with a liner employing special resins which form a watertight, anti-corrosive barrier, giving a high chemical resistance to chemicals.

An outer fibre-glass shell is then applied to the liner using a bobbin winding process.

We supply all well known manufacturers of GRP filters including Astral, Certikin, Calplas and Waterco.

Our mild steel filters are manufactured to current guidelines and typically have 8mm thick plate on the shell and 12mm thick plate on the dished end.

The filters come complete with 600mm side and top mounted access Manways with bolted lids.

The filter internals have an upper bell mouth system and a lower lateral set manufactured from PVC connected to a central PVC header the underdrain system supported on a concrete base. We can alternatively supply steel filters with nozzle plates and an optional sight glass. All of our steel filters are manufactured to comply to current BS standards.

Filters can be manufactured in various diameters depending on the application required.

The filters are manufactured from fibreglass and polyester resin; the internal pipework and distribution system is manufactured from PVC and polypropylene.

Plant rooms can be congested and have limited access and when filters fail and require replacement, it is not possible to get filters into the plant room.

We can offer a solution to this with our split filters which come in a variety of sizes from 1.2m to 1.8m diameter.

They can be delivered in two parts and assembled on site in the plant room. The two halves seal perfectly, using double o’ring and held together by a flange using bolts and nuts. The filter is specifically designed to fit through existing standard size plant room doors.

Sterling also supply and install new generation filters which offer improved water quality and operational cost savings. Click on this link for more details.

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Filter Media Change

As standard we remove existing filter media from the vessels using our specialist vacuum tanker unit rather than manual removal.

This method of media removal is quick, safe and helps to avoid unnecessary mess and difficulties that can be encountered with this type of work when carried out manually. Safety is of prime importance and this method of removal minimises the risk for this part of the works by removing the need for manual handling of the media to skips and reducing vessel entry requirements.

If there is no site access available for a vacuum tanker, this will be discussed with the client to ensure we can offer media removal manually as safe as possible.

All redundant filter media is disposed of off-site to registered landfill sites only in accordance with current legislation. Our price always allows for disposal costs.

The filters are manually charged with the correct quantities of selected grades of silica sand, which shall be limestone and clay free, or recycled glass or AFM if preferred.

Delivery of media to site will be in 25 kg bags on pallets, in accordance with current EEC manual handling regulations / guidelines.

Filter Refurbishment

Sterling offer a complete package for the refurbishment of steel filters. Our services include ultrasonic thickness testing of filter vessels to confirm they are suitable for refurbishment.

Once deemed suitable, we remove existing media using a vacuum tanker or manually by hand.

We then shot blast and relining the internal surfaces of steel filter vessels. For relining, we use solvent less 2-coat or 3-coat epoxy paint lining system which can be hand applied or sprayed.

We can also replace existing lateral and nozzle plates systems and header pipe work. We can also provide repairs on concrete underbeds.

Where multiple swimming pool filters are to be refurbished, this can take place in stages, allowing the pool to remain in operation whilst the refurbishment takes place.


Confined space regulations states that access manways on filters vessels must be at least 600mm in diameter. If the size of the manway is smaller than this, it will need to be upgraded.

Sterling can supply and install new 600mmØ manways on steel filter vessels to comply with current confined space entry requirements. Typically, we will conduct these works in conjunction with a filter media change and refurbishment.

Isolation Valves

We can supply and install a range of valves from 3/8” to 16” diameter diameter from all the major valve manufacturers.

Typical construction of our isolation valve is wafer butterfly type with cast iron bodies, stainless discs and EPDM seals. We can supply either lever or gearbox operated valves.

Circulation Pumps

Our installation team can offer a range of circulation pumps for swimming pool applications. Typically, pumps are non self-priming, single stage end suction pumps for use on thin, clean water slightly contaminated, but without abrasives. Self-priming pumps are available if required.

The pumps we offer for smaller applications are manufactured in Polypropylene and fibreglass complete with a stainless steel shaft and a Carbon Ceramic seal. The Impeller is manufactured from polypropylene and fibre glass with IP55 classification waterproof sealing. These units generally come complete with an integral Strainer Box and Strainer Basket.

The Pumps we offer for larger applications have cast Iron housing and volute and a stainless steel shaft and come complete with Bronze Impellers and Seals for use on Chlorinated Pool water. The Pumps are connected to an electrical Drive motor via a stainless steel shaft. These units are generally, standalone pumps and require a separate Strainer Box and Basket to be installed in line with the Pump Suction.

The motors we offer range from Class IE2 Design to Class IE5 Design. New technology pumps are offering built in inverter drives to offer greater energy saving potential.

Energy Saving Products

Flow Meters

A working flow meter is an essential piece of equipment in a swimming pool plant room. Pool plant operators need accurate information on pool circulation rates to ensure they can measure the performance of their water treatment system and identify any issues quickly.

A flow meter is required on each individual swimming pool and should be installed after the circulation pumps and before the filter vessels.

Sterling can supply and install both Analogue and Digital flow meters.

Typical construction is a stainless steel orifice plate which is installed in the circulation pipework which is supplied with an analogue dial gauge to indicate the flow measurement. It works by measuring the pressure drop across the orifice plate which is one of the most widely accepted methods for determining flow. Reliability is assured as there are no moving parts which could cause a failure.

This type of flow meter is available as standard for pipe sizes up to 12”. Larger units are available on special request.

Digital meters are typically electromagnetic flow meters which offer greater accuracy over analogue meters as well as increased functionality such as data logging and connectivity via analogue or digital outputs.

The flow meter sensors are installed into the circulation pipework as normal. Flexible installation options allow the digital sensors to mounted together with the display unit or separate if preferred.

There is minimum maintenance with digital meter as there are no moving parts and typically, they have self-cleaning sensor electrodes.

This type of flow meter is available for pipe sizes up to 48” so more than adequate for swimming pool applications.


Each circulation pump needs protection from swimming pollution such as hair, plasters, jewellery etc. A strainer box is fitted upstream of each pump on the suction side to offer protection.

Construction of a strainer is typically a strainer basket made of uPVC or stainless steel with a mesh size of 3mm which is housed in a strainer box made of uPVC/GRP or stainless steel.

Sterling can supply and install either type of strainer in sizes from 1½” (50mm) to 16” (400mm)

Balance Tank Remedial Works

Pool Water Treatment Advisory Group (PWTAG) recommend that balance tanks are drained down, inspected and cleaned at least once per year. Unfortunately, many balance tanks are neglected as they can be difficult to access without the correct knowledge, expertise and training.

Sterling have a team of engineers who are confined space trained and can offer a cleaning service as well as a range of remedial works on balance tanks during normal or out of hours if preferred.

Typical works as below:

  • Yearly disinfection clean and inspection
  • Repairs to internal pipework
  • Repair and installation of isolation valves
  • Repair and installation of flow valves
  • Repair and installation of automatic level sensor systems

Dosing Controllers

Due to variations in water quality due to bather loads, pool activity etc, it is best practice to automate the chemical treatment of swimming pools. There are many dosing controllers available which can as a minimum control both disinfectant dosing and pH adjustments.

Sterling can supply and install all major dosing controller models available. We also keep in stock our preferred controllers so we can offer an immediate response to any breakdowns on our customer sites.

Below are our preferred dosing systems:

The Bayrol compact is manufactured to a high standard and therefore has been proven to be an extremely reliable dosing system. It is our most cost effective solution for online measuring pool water parameters and automatically dosing chemicals when needed.

The controller is easy to use with a simple menu structure, touch screen operation and high resolution 5.7” display screen. It also has a comprehensive monitoring and alarm functions.

The Ezetrol® touch controller is specifically designed for commercial swimming pools with the latest technological advances. As standard the controller measures pool water free chlorine, pH and temperature. An ORP and conductivity measurement can be added as an optional accessory.

The controller has an intuitive operation, touch screen operation with a 4.3” colour display screen.

A key feature is the flow cell module which includes a flow control valve. This feature ensures correct operation when the pool circulation is being controlled by a Variable Speed Drive (VSD).

The controller provides signal outputs to a variety of chemical feed devices to control the free chlorine residual, the pH value and the conductivity at their respective setpoints. It also has advanced communication options via RS 485, USB and Ethernet interface, Modbus TCP

Chemical Dosing and Control Systems

Commercial swimming pools can vary enormously in design, size, turnover and bathing loads all of which need to be taken into consideration when choosing the specification and type of dosing equipment and controller for the pool.

Whether it is for a standard 25m x 13m pool or a 50m competition pool, it is important that the analysis of the incoming water supply is taken into consideration to ensure compatibility with the chemicals being used for the dosing and PH correction.

If you need to dose sodium or calcium hypochlorite, acids or alkalis, granular, tablet or liquid - Sterling can provide the knowledge and advice to help you select the right chemicals for your application. In addition, Sterling can provide comprehensive range of dosing pumps, tanks, bunds and feeders to suite a wide range of applications.

Sodium Hypochlorite (available in 14/15% carboys or <1% onsite generation using a Hyprolyser)

Calcium Hypochlorite (available in 65-70% in granular form)

Sodium Bisulphate
Hydrochloric Acid

PAC is a flocculent and is used to increase the filtration efficiency by causing small particles to bind together which can then be more effectively removed by sand filters. In general terms, the clarity of the pool water increases significantly when using PAC as less suspended matter passes through the filters.

Some of these small particles are bacteria and although chlorine will destroy bacteria and oxidize organic materials, they remain in the water as a suspended solid and without PAC are too small to be removed by sand filtration alone.

PWTAG recommends flocculation to prevent filter breakthrough of Cryptosporidium (99.9% removal). Because of this PAC is being retrofitted to many existing installations for the benefits previously given and on new swimming pools they have become the norm.

Sterling can install PAC dosing systems on new or existing installations and can be used on all types of pools from leisure, competition and learner pools.

Did you know your plant room could be subject to chlorine gas, a potentially fatal and extremely harmful gas? Are you and your staff protected from a chlorine gas incident? This is where a gas detection system provides an important solution.

This flexible multi-function device warns the operating personnel if a defined concentration of gas is reached in the air, alerting them to evacuate to safety. Typically, there is a flexible two channel measuring system designed for gas monitoring in up to two rooms. It can either use a single Chloratect sensor or a pair of Chloratect sensors to measure chlorine gas.

The gas concentrations are displayed on the display panel. The peak and average values over the past 8 hours can also be displayed. The desired alarm levels can be set using the menu via a control pad. Two values per channel can be specified. An alarm contact is activated for each limit value and the system will also set off an audible and a visual alarm.

Sterling can supply, install and commission gas monitoring systems to suit all pool requirements.

Hyprolyser Chemical Dosing

Bulk Chemical Storage

The use of bulk storage tanks as part of the chemical dosing systems are common in leisure centres with large or multiple swimming pools. Sterling can install a range of tank sizes manufactured in uPVC/GRP or Polypropylene.

The choice of material is an important one as it must be compatible with the chemical to be stored. In general, our recommendation would be a tank manufactured in uPVC Lining/GRP Reinforced as it offers a service life of 20 years when used in swimming pool applications.

The tanks can be either delivered complete or where access is restricted can be built in sections on site.

Sterling can also install chemical dosing bunds, which can be designed to suit the size and application required.

Chemical Bund Relining

Over time, the integrity of a chemical bund lining may be compromised and require repairing. Common issues seen are damage caused by accidents or poor general maintenance.

This can be a significant safety concern as there is a high chance of chemicals leaching out of the bund and causing a hazard.
Sterling can offer a bund relining service to repair the bund and reline in accordance to current standards.

  • Yearly disinfection clean and inspection
  • Repairs to internal pipework
  • Repair and installation of isolation valves
  • Repair and installation of flow valves
  • Repair and installation of automatic level sensor systems

Control Panel Installation

We can design and build PLC driven Control Panels for Swimming Pools filtration and water treatment systems.

Our control panels allows the user to control equipment such as Circulation Pumps, Variable Speed Drives, Air Scourer, Automatic Valves, Dosing equipment etc. We can program feature such as automatic backwash if requested.

Typical panels will have a minimum 1.5mm sheet steel enclosure, damp and dust proofed and fitted with a 2mm hinged and gasketed door. The panel will house all necessary starters for each of the electrical items associated with the filtration system and be complete with mechanical interlocking isolator on the door and inclusive of all necessary fail-safe requirements. Front of panel includes all necessary start and stop switches, run and trip lights etc. with the facility to connect to customer BMS systems.


We offer a complete package for both new and refurbishment of existing spas from initial design through to installation and commissioning.

We have a wide choice of commercial overflow spas available and vary in shape, style and size from a small 3 seater to the larger 9 seater spa, each installation can be designed and tailored to meet the customer needs.

  • Yearly disinfection clean and inspection
  • Repairs to internal pipework
  • Repair and installation of isolation valves
  • Repair and installation of flow valves
  • Repair and installation of automatic level sensor systems

Sauna and Steam Room

We offer a range of sauna and steam rooms from standard ‘off the shelf’ products to tailored rooms based on specific customer requirements.

Our commercial sauna’s typically come inclusive of ceilings, wall, benches, backrests, heater, control unit and lights.

Our commercial steam rooms typically come inclusive of ceilings, walls, seats, steam room door, steam generator, lights and vents. We also provide a tiling service with these rooms.

Ladders and Hand Rails

Sterling can provide a range of poolside products including ladders and hand rails.

Our ladders and hand rails are typically manufactured in 38mm or 50mm stainless steel for durability in swimming pool environments.

All products are designed to the highest standard and are suitable for new and refurbished pools.

  • Yearly disinfection clean and inspection
  • Repairs to internal pipework
  • Repair and installation of isolation valves
  • Repair and installation of flow valves
  • Repair and installation of automatic level sensor systems