Pond plumbing, drains, valves and fittings
At Koi Water Garden, we are able to offer competitive prices on not only high quality koi, but also on koi related goods such as all necessary pipe work and fittings.
last updated 30th July 2020
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Top tips for plumbing your pond.
Pond plumbing may seem like a complete mystery to many, who quite understandably tend to think of plumbing in a Koi pond in a similar way to plumbing in a house. There are however few similarities, not only with the materials and pumps used, but also in the level of complexity. Pond plumbing need not, and indeed should not be complex. there are two basic plumbing systems – one for gravity filter installations and one for pump fed.
In pump fed installations the filter pump is operating in the pond and this is normally connected to the filter inlet with flexible piping. The UV unit should be installed between pump and the filter inlet and any heater or heat exchanger fitted should also be fitted in the same position either directly before, or after, the UV and before the filter inlet.
Always fit a suitable slide or ball valve immediately before the filter inlet so that the pond and filter can be separated and water kept in the filter with the pump switched off. Input pipe work from pump to filter which is under pressure should be minimum 1.5” to avoid unnecessary flow losses.
Remember to keep pipe runs as short as possible with as few bends as possible and also remember to trim any universal hose tails fitted (often supplied with pumps and Uvs) to the maximum diameter possible – again to avoid flow restrictions.
Insufficient pipe diameters and too many restrictions can reduce the rated pump output by over 50% and put back pressure on the pump leading to premature failures.
With pumped installations, the filter must be above the water level in the pond so that water can be returned to the pond by gravity.
On the return side of the filter, one would normally use a minimum of 2” pipe work to return water to the pond. Because the water return operates under gravity a bigger pipe diameter will be needed to cope with the pump flow. Also the longer the return pipe work, the larger the diameter the pipe needs to be, so we would normally recommend a practical minimum pipe size of 3” for pumped filter returns. It is also normally simpler to step up a pipe size rather than using multiple smaller pipe returns. A single 3” pipe has a larger bore area than 2 x 2” pipes and a single 4” pipe has a larger bore area than a two 3” pipes. So in this respect at least size matters!
With gravity installations, the water level in the filter is the same as the water level in the pond, so gravity filters normally reside in purpose made filter chambers which are excavated at the same time as the pond in order to simplify construction.
In gravity installations, the filter input is fed by pressure of gravity, which forces water through a large (normally 4”) pipe buried in the floor of the pond or fitted low in a side wall and into the filter.
A 4” diameter pipe is chosen since water flow through it is slow, and solids carried into the filter arrive intact, this means the filter can cope with these solids more efficiently, and remove them more easily.
The 4” pipe is normally connected in the pond to a large sump type bottom drain which when installed allows water ingress via a small peripheral gap which prevents fish from entering the pipe work, but allows all the unwanted solids to pass. The connecting 4” pipe is run horizontally in the ground or concrete slab under the pond and then exits vertically into the filter chamber in a suitable position ready to connect to the filter inlet. Always fit a suitable slide or ball valve immediately before the filter to separate pond from filter for cleaning and purging purposes.
On the return side of the filter, water is drawn from the filter by a suitable pump, which should always be mounted below water level and which is then connected to a suitable UV (and heater or heat exchanger if fitted), and then to pipe returns normally fitted into the pond walls. The return pipe work is normally 1.5” with a gravity installation, as here the returned water is under pressure. Again never use pipe work less than 1.5” in diameter, and if pipe runs are very long, step up the pipe diameter to 2” to avoid frictional flow losses in the pipes. Similarly avoid too many sharp bends in return pipe work, and use swept bends wherever possible. Always fit a suitable slide or ball valve immediately after the filter, and before the pump in order to separate pond and filter to allow for maintenance of pumps and UV and to allow for cleaning of the filter.
It is always a good idea to use at least two pond returns, located at opposite corners of the pond, which will help to maintain a circular flow, even in square or rectangular ponds, and this helps to "wash" the floor of the pond and encourages dirt to move to the centre of the pond base where the bottom drain should be located.
With two (or more) returns operated from one pump, remember that balancing valves should be fitted to the shortest return pipe runs so that the flows through all of the return pipes can be equalised. If these are not fitted, most of the pumped water returning to the pond will exit the shortest pipes only as it will follow the path of least resistance.
Top Tips for Pond Plumbing.
- Never put installed pipe work under stress – there is limited pressure in Koi pond installations, but long unsupported pipe runs full of water and pipes forced into positions they don’t really want to be in are asking for trouble.
- Always used solid glued pipe work wherever possible, and NEVER use ANY push fit components.
- Always fit pipe runs dry first and mark joints and angles with a felt pen so that they can be removed and then glued in the correct position.
- Always glue the shortest pipe runs first – you will have more flexibility to move, remove and refit long pipe runs more easily because the long pipe will flex and allow more movement.
- Always use ball valves in any pipe work to control flows.
- Always use slide valves as waste or stop valve only so that when in use they are shut.
- Preferably always mount them in vertical pipe runs.
- Never use slide valves in a horizontal pipe run so that they are open when in use, they will fail within months as the shutter grooves fill with dirt and prevent the shutter from closing properly.
- Always use a minimum of 1.5” pipe work for pipe runs under pressure and minimum 3” for gravity flow pipe work.
- Increase pipe diameters as pipe runs becomes longer.
- Always use swept bends rather than knuckle bends wherever possible.
- Always use pressure pipe for buried pipe runs and bed such pipe runs in sharp sand or pea shingle to allow for movement.
- Similarly always use pressure pipe for any pipe runs that are exposed and liable to be stepped on, kicked or are otherwise vulnerable to damage.
- When plumbing waste pipe work from filter/vortex drains, always step up fitted pipe sizes to a minimum of 2” to avoid any possibility of the pipes becoming clogged with weed and/or leaves and other detritus. Always use swept bends in waste pipe work.
- Always install Pumps, Uvs, Heaters etc using demountable single union connectors so that all components can simply be removed for maintenance.
- Always install valves immediately before and after filters (gravity installations) and near pond returns so that all elements of the filter system can be removed without water being drained from the pond or filter.
- In pumped systems always use reinforced flexible piping from the pump and NEVER sit the pump on the pond floor – always at least 12” above the base of the pond. In this way should there be a disaster, the pond can never be completely emptied and the fish will be safe.
- It is good practice to use a dedicated pump for the filter flow, and to use separate pumps for other water features such as waterfalls and skimmers, which may need to be switched on and off, or may operate with variable water flows.
Valterra Slide Valves
Valterra slide valves are tough and dependable - made to last! Designed to fit imperial PVC pressure pipe. Will fit solvent weld waste with suitable adaptors (see below). Mainly used for on/off waste valves in filters and to separate filter from pond, to completely shut off flow when required. Not suitable for flow restriction or control.
|4" Steel shutter||£49.95|
Double Union Ball Valves
Ball valves are ideal to restrict pipe flows, as purge valves and waste control valves. Easy to dismantle and maintain and very strong - fits standard imperial PVC pressure pipe. Will fit solvent waste with suitable adaptors (see below). Adjustable for pressure and therefore will never leak.
Pipe adaptors - Solvent waste to PVC pressure piping
Pipe adaptors enable the use of ball valves, slide valves and other fittings that are imperial (English) pipe sizes to fit metric waste pipe. Simply glue over the end of the solvent weld waste pipe before fitting to the appropriate valve or fitting. One required for each side of the valve.
|40mm - 1.5"||£0.95|
|63mm - 2"||£1.25|
|82mm - 3"||£1.95|
|110mm - 4"||£2.25|
Universal 2 inch to 1.5" converter fitting
This is a really simple and great idea - a fitting which can be used on 1.5", 40mm, 2" and 50mm pipe work, and can convert from solid piping to flexible all in one fitting. The rear end of the fitting, shown below left, features a 1.5" BSP female thread on the inner side and a 50mm solvent weld fitting on the outer. With the addition of a 50mm pipe adaptor, this solvent weld fitting is instantly converted to a 2" imperial fitting. The front end of the fitting , shown below right, will allow the connection of a 2" or 50mm flexible pipe on the outer connection or a 40mm solvent weld pipe fitting on the inside. Clever or what!
|1.5 - 2 inch||£4.95|
In wall skimmer
In pond design with floating weir plate to prevent koi entering skimmer whilst chasing food. Also complete with catch basket and removable lid for easy cleaning. Will suit liner or concrete ponds - complete with rubber gaskets and screw in flange plate in order to fit to liners. When fitting to concrete block walls, standard skimmer replace 1/2 of a 450mm concrete block. The wide mouth skimmer replaces a complete block.
Can be fitted to either solvent waste or PVC pressure pipe with relevant fittings (not supplied). We offer both pumped and gravity feed options with our skimmer range. Pump feed versions come with a 1.5" female threaded outlet. Gravity feed models, which are suitable for feeding pond water to drum or other types of pre-filters in a gravity filter installation come complete with an 82mm female solvent weld outlet.
Above: - Skimmer guard Plate.
|Standard In wall skimmer approx 9" wide x 9" deep at face with 1.5" bsp female threaded outlet.||£36.50|
|Standard In wall skimmer approx 9" wide x 9" deep at face with 82mm gravity feed outlet.||£46.50|
|Wide mouth in wall skimmer. Complete with screw on wide angle mouth approx 15" wide at face x 9" deep with 1.5" bsp female threaded outlet.||£49.50|
|Wide mouth in wall skimmer. Complete with screw on wide angle mouth approx 15" wide at face x 9" deep with 82mm gravity feed outlet.||£59.50|
|Grid pattern skimmer guard. Replaces standard skimmer front plate - standard size||£24.50|
|Grid pattern skimmer guard.Replaces wide mouth skimmer front plate - widemouth size||£29.50|
Above:- Standard In wall skimmer.
Above:-Wide mouth Skimmer - supplied in Black
Above : Gravity in wall skimmer
Oase Profi In wall skimmer
Oase have produced a new gravity feed in wall skimmer. This is a large and professionally designed heavy duty skimmer with built in top up point/overflow and removable debris catch basket. The heavily ribbed body is designed to be securely cemented into concrete block walls. Will suit liner or concrete ponds - complete with rubber gaskets and screw in flange plate in order to fit to liners. When fitting to concrete block walls, standard skimmer replace apporox 50% of a 450mm concrete block. The wide mouth skimmer extension replaces a complete block.
Designed to fit 110mm pipe work
|Standard In wall skimmer 273 x 267 x 408 mm high with 110mm outlet socket.||£199.50||standard extension kit - the skimmer sits behind a standard 225mm (9" block) wall.||£89.50|
|wide mouth extension kit 420 x 267mm - the skimmer sits behind a standard 225mm (9" block) wall.||£179.50|
Above:- Profi skim.
Above:-Profi skim wide mouth exension
Large sump bottom drain.
Features removable lid with screw on flange ring for fitting to liner or concrete ponds. 110mm version suitable for standard solvent weld waste pipe work and 4" for imperial PVC pressure pipe work.
|4 Inch imperial||£39.50|
Bottom drain converter socket
A special PVC pressure fitting that converts a 110mm metric bottom drain to a 4 inch imperial version. The socket features a male metric spigot for solvent weld waste pipe on one side and a 4 inch imperial socket to take pressure pipe on the other. Great idea and a very economical way of converting from a normal 110mm economy bottom drain to a 4 inch pressure version.
|Bottom Drain converter socket||£12.95|
Imperial/Metric converter socket
A special PVC pressure fitting that converts European metric pipework to BS imperial. The socket features metric for solvent weld waste pipe on one side and imperial socket to take pressure pipe on the other. Great idea and a very economical way of converting to pressure pipe sizes from Eurpean metric pipe sizes.
|50mm female/ 1.5 Inch female||£2.95|
|63mm female/ 2 Inch female||£3.95|
Bottom Entry Side drain
Features removable lid with screw on flange ring for fitting to liner or concrete ponds. 110mm base entry pipe normally used when fitting drains in side walls of ponds. Can still be used mounted in pond base if required
|110mm side drain||£19.50|
Aerated bottom drains.
Based on a 4" or 110mm large sump bottom drain, this aerated bottom drain has a 1" bottom entry for running airline into the drain via a separate 1" pressure pipe running alongside or underneath the main 4" bottom drain pipe and into a 34cm perforated drain lid which replaces the standard drain cover. (shown right). So the 1" pipe is the air feed and no separate flexible air piping is required. The perforated drain lid can simply be unscrewed from the central drain spigot when required for cleaning - for example.
Specify 110mm size for solvent weld waste pipe and 4" size for imperial pressure piping.
|4 Inch Imperial||£134.00|
Retro fit bottom drain cover assembly
A brilliant and simple idea to replace bottom drain covers (lids) that have either come off on their own or been removed, which are always very difficult to get back on once removed without going for a swim!
These heavy duty drain covers are assembled with 3 stainless steel bolts and a heavy bottom ring.
Just push into the bottom drain cavity with a net or similar to position, and can be lifted out easily with a net, for bottom drain cleaning.
Fits all standard large sump bottom drains.
|110mm or 4 Inch||£79.95|
Double Union PVC Non Return Valve
Provides a simple means of preventing backflow in pipe work where this would be undesirable. Made of UPVC with 1.5" or 2" solvent weld fittings. Demountable for cleaning.
It can be extremely difficult to calculate flow rates for any system - final flow rates depend on many factors, pump power and design, siting, pipe sizes, number of bends and fittings used in plumbing, and the various equipment used with the water flow such as UVs, heaters etc. Measuring final flows is however very important, to ensure that you are turning over the pond water as appropriate - normally every 2 - 4 hours through your filter system.
So we are now able to offer an accurate flow meter at a very realistic price.
- Direct Reading Scales
- Impact-Resistant Machined Acrylic Body
- Factory calibrated
- Easy-to-Read Scales
- Wear- and Corrosion-Resistant 316 SS Floats
- Available to fit pipe sizes from 1.5 to 4"
- Capacity:- 20 to 7200 litres/min
|flow meter for 1.5" pipe size.||£109.50|
|Flow meter for 2" pipe size.||£119.50|
|Flow meter for 3" pipe size.||£139.50|
|Flow meter for 4" pipe size.||£149.50|
Metric waste pipwork
Please note that all pipe work can be supplied mail order - but carriage charges for 3m pipe lengths will be higher than those shown in the shopping cart as parcel lengths of over 2.5m are surcharged by all couriers - carriage will always be charged on 3m lengths of pipe work regardless of order value. We will confirm charges by return mail for each order placed. Alternatively ask to have your pipe lengths cut in half - that way normal carriage charges will apply.
|pipe 3 metre length||£9.50||£14.50||£29.95||£29.95|
|90 deg swept bend||£2.00||£3.00||£14.95||£14.95|
|45 deg bend||£2.00||£3.00||£14.95||£14.95|
Heavy Duty Reinforced flexible piping.
Our reinforced flexible piping is a very strong, thick walled PVC based tubing that is reinforced for extra strength. Cannot be crushed and is very difficult to damage or distort. Designed to be mechanically fitted via an appropriate sized hosetail. Can also be solvent weld glued. Ideal where difficult, complex pipe runs are necessary. Will not split or go brittle with time.
|1.5 inch priced per metre||£3.95|
|2 inch priced per metre||£5.95|
Pressure Flexi - bondable flexible tubing
Pressure flexi is a very strong, thick walled PVC based tubing that is reinforced for extra strength. Cannot be crushed and is very difficult to damage or distort. Designed to be solvent welded into metric and imperial pressure pipe fittings and is therefore ideal where difficult, complex pipe runs are necessary. Ideal for underground as well as above ground applications. Will not split or go brittle with time.
|50mm Pipe per metre Metric/ imperial converter required for imperial pipe||£7.95|
|63mm Pipe per metre. Metric/ imperial converter required for imperial pipe||£11.95|
|50mm / 1.5" adaptor socket||£2.95|
|63mm / 2" adaptor socket||£4.95|
Solvent Weld Waste pipe Fittings
Above:- Male threaded solvent socket
Above:- Flanged Tank Connector
Above:- Screw type Tank Connector
|Male threaded socket||£1.95||£2.95|
|Tank connector screw type||£3.50||£4.50|
|Tank / Liner connector flanged type||£3.50||£4.95||£6.95||£8.95|
Other Solvent Weld Waste Fittings
Reducers and Hosetails
|Reducer 2 - 1.5"||£1.95|
|Reducer 3 - 2"||£3.95|
|Reducer 4 - 3"||£4.95|
|Stepped hosetail - glued 3/4" to 1.5"||£2.25|
|Stepped hosetail male threaded 3/4" to 1.5"||£2.25|
Above:- Stepped Hosetail - glue fit shown
Flexible Rubber Connectors
These rubber connectors are the answer to many a Koi pond plumbing problem - where there are joints and angles that are not quite 90 deg or in line these fittings can be used as they are flexible and 'give' to allow strain free pipe joints. They are also ideal for use where both metric and imperial plumbing has been use as they will fit to either system. They are also convenient for any joints that need to be removed from time to time and don't need to be glued as a permanent fixture. Complete with terry clips that will tighten with a socket or spanner as well as a screwdriver for sure watertight joints. These joints are heavy duty and very thick walled and will not deteriorate with age.
|Size||Rubber Socket||Buy||Size||Rubber 90 deg Bend||Buy||Size||Rubber T Joint||Buy|
|1.5 inch||£5.50||1.5 inch||£8.75||1.5 inch||£10.45|
|2 inch||£6.00||2 inch||£10.95||2 inch||£12.55|
|3 inch||£9.00||3 inch||£15.70||3 inch||£22.00|
|4 inch||£12.00||4 inch||£20.95||4 inch||£29.95|
These rubber connectors are the answer to many a Koi pond plumbing problem - simple reducers to bridge different pipe sizes without the need for glued joints and reducers - Very handy for both metric or imperial pipe sizes, will fit both standards
|2 - 1.5"||£4.95|
|3 - 2"||£8.95|
|4 - 3"||£9.95|
|4 - 2"||£9.95|
|6 - 4"||£19.95|
Rubber End Caps
Handy to block up pipes either as a temporary or permanent measure - again fits equivalent metric or imperial pipe sizes.
|1.5" Rubber end cap||£2.75|
|2" Rubber End cap||£3.75|
|3" Rubber end cap||£4.95|
|4" Rubber end cap||£5.50|
PVC Pressure Pipe
PVC Pressure pipe is the standard for all Koi plumbing work. Supplied as class C D or E, pressure pipe is thick walled PVC and is very strong when compared to waste pipe work. It is recommended for all underground use and will withstand much higher pressures and stresses than normal waste pipe work. In particular it is recommended for all bottom drain pipework, or any pipework that is to be permanently buried in soil or under concrete.
Please note that all pipe work up to 3m lengths can be supplied mail order - but carriage charges for 3m pipe lengths will be higher than those shown in the shopping cart as parcel lengths of over 2.5m are surcharged by all couriers - carriage will always be charged on 3m lengths of pipe work regardless of order value. We will confirm charges by return mail for each order placed. Alternatively ask to have your pipe lengths cut in half - that way normal carriage charges will apply.
** We also supply pressure pipe in 6m lengths (see below), but these are only available for collection - we cannot ship these lengths by courier **.
|Type||3/4 inch||Buy||1 inch||Buy||1.5 inch||Buy||2 inch||Buy||3 inch||Buy||4 inch||Buy|
|1 metre pipe length||£3.65||£4.00||£4.50||£6.99||£12.35||£15.10|
|3 metre pipe length||£9.95||£10.95||£12.95||£18.95||£33.65||£41.45|
|6 Metre pipe length **||£17.95||£19.75||£22.05||£34.10||£60.55||£74.75|
|90 deg knuckle bend||£1.75||£2.10||£2.95||£3.95||£13.95||£17.95|
|45 deg bend||£1.75||£2.10||£2.95||£3.95||£13.95||£19.95|
|90 deg Swept bend||£4.95||£5.95||£7.85||£12.35||£27.95||£39.95|
|Equal "T" joint||£1.85||£2.25||£2.95||£4.95||£17.95||£21.35|
|PVC Pipe clip||£1.35||£1.55||£1.95||£3.25||£6.15||£7.25|
PVC Pressure pipe - threaded sockets and unions
Above:- Male threaded socket
Above:- Female Threaded socket
Above:- Single union de-mountable connectors - 1 Male thread, 2 plain glued, 3 female thread. Fit to pumps and UVs for ease of removal.
|Type||3/4 inch||Buy||1 inch||Buy||1.5 inch||Buy||2 inch||Buy||3 inch||Buy||4 inch||Buy|
|Threaded female socket||£2.75||£3.85||£5.55||£7.85||£17.50||£24.95|
|Threaded Male Socket||£1.75||£2.25||£3.95||£5.95||£13.75||£20.75|
|Female Threaded socket union||£5.95||£6.55||£9.95||£16.75||£53.95||£64.25|
|Plain socket union||£5.65||£6.75||£8.95||£15.75||£51.95||£59.95|
|Male Threaded socket union||£6.95||£8.55||£9.95||£16.75||£53.95||£64.25|
Used to reduce pipe sizes from 4 inches right down to 3/4 inch if required. These are all gluable fittings, and are designed to fit into any standard pipe fitting of the larger size.
|Reducer 4 - 3"||£8.95|
|Reducer 4 - 2"||£8.95|
|Reducer 3 - 2 "||£6.35|
|Reducer 2 - 1.5"||£2.95|
|Reducer 1.5 - 3/4"||£2.95|
|Reducer 1 - 3/4 "||£1.65|
Imperial PVC tank connectors
Used to connect most sizes of imperial pressure pipe to tanks and pond liners.
|1.5 inch Tank connector||£7.95|
|2 inch Tank connector||£9.95|
|3 inch tank connector||£12.95|
|4 inch tank connector||£13.95|
Solvent weld cement
Tangit professional rapid cure solvent cement for solvent weld waste and all classes of PVC pressure and ABS waste piping. Cans complete with applicator brush. Tangit is by far the best solvent weld cement for professional use. Gap filling and slow grab allows time to move pipe joints once cemented. We suggest you use small cans (with small brushes) for 1.5 and 2" piping and large cans (with large brushes) for 3 and 4" piping.
Griffon professional pipe cleaner for solvent weld waste and all classes of PVC pressure and ABS waste piping. Cleans and de-greases pipe work in preparation for cementing. Ensures a complete and correct bond. Supplied in 500ml cans.
|500ml Griffon Pipe cleaner||£12.95|