Pool Info: Swimming Pool Skimmers
Pool Wall Skimmers perform the important task of removing floating debris from the pool, before it sinks to the bottom and creates work for you or your automatic pool cleaner. Functionally, skimmers are quite simple. They attach to the top wall of the pool and underneath, to the skimmer pipe.
The interface of the plastic pool skimmer to the concrete pool creates many opportunities for problems to occur. Common skimmer problems include separation from the pool wall (beam), freeze damage, leaking, or collapsed, broken or separated plumbing pipes.
Pool wall skimmers need regular maintenance, repair and replacement.
Inground Pool Skimmer Replacement
Skimmer replacement involves removing the coping stone over the skimmer, cutting the 2x2’ concrete pad on top of the skimmer and the concrete that surrounds the skimmer well. Then the skimmer is pried and pulled off the wall, and the pipe(s) beneath are cut-off. The new skimmer is secured to the wall and after plumbing is reconnected (and tested), the concrete pad and coping stone is replaced over and around the new skimmer.
Skimmer replacement is often done during renovation, or by itself if necessary. Skimmer replacement costs at least $1,500 for an inground pool, but only $150 for an aboveground pool. Why so much money to replace a $75 plastic box? It is not a simple procedure, skimmer replacement is hard work!
To replace an inground pool skimmer, the concrete deck is cut around the skimmer, and then the concrete that encases the skimmer well must also be removed. Pry bars and small jackhammers can help remove the skimmer from the wall of the pool. After removal, a new skimmer is attached to the pool wall by plumbing it in place, and pinning bent rebar around the skimmer, pegged into the back of the pool wall. Leave a ½” gap on sides and front of skimmer (pool side) to parge in place with plaster. A wooden box or form is then built around the skimmer, and new concrete is poured around the skimmer body, but only about halfway up the skimmer, to hold it in place against the wall. To finish on the pool side, pack in thick and deep with pool plaster mix around where the skimmer meets the pool wall, on both sides and the bottom, all 3 sides of the skimmer opening. Backfill tightly around the skimmer, supporting the block of concrete wrapped around the skimmer. Tamp in place gravel for the top 3-4 inches above the backfill and concrete.
To pour a new concrete pad around the top, level with the pool deck, use plastic or wood crack strips around the skimmer, or use flat foam with tear off strip, like Deck-O-Foam to leave an expansion joint for caulking later. With 4 pieces of 3/8” rebar cut to fit, make a ‘tic-tac-toe’ board, tying together the rebar, to fit around the skimmer. Elevate the rebar cross off the gravel by 1-2”, so it will sit in the middle of the concrete pad. Now mix up a good concrete mix (sidewalk/driveway type), and pour it on top of the gravel, up to the very top edge or lip of the adjustable skimmer collar (remove the skimmer lid and duct tape the top, to keep the skimmer clean). Push into place and trowel smooth and level, and after 30 minutes, drag a broom across the surface for texture.
The process for replacing a vinyl inground pool skimmer is the same, with the exception of pinning rebar to the pool wall, and parging with plaster mix. Vinyl inground skimmers connect to the pool wall with screws and gaskets, and must be supported well and backfilled carefully, to avoid putting stress on the pool wall.
Older pools sometimes used Flex PVC pipe to connect to the skimmer, underground. Flex pipe can crimp, usually where the pipe turns, underneath the skimmer. Using chlorine tablets in skimmers for many years can lead to this problem. It’s best to use rigid PVC beneath the skimmer, even if you don’t put chlorine tablets into the skimmer (which you shouldn’t).
Pool Skimmer Plumbing
Inground pool skimmers can have a single hole in the bottom, or they are also designed with 2 holes in the bottom. The two-hole design gives plumbers some flexibility in plumbing, and specifically it allows a pool builder to connect a main drain pipe into the skimmer, into the front hole, and connect the back hole to a pipe that runs to the pump. This is a cheaper way to build a pool, because you don’t have to run a separate drain pipe all the way to the pump, with a separate valve.
To replace skimmers not connected to the main drain, one of the holes will come with a plug. Pull out the plug, apply PVC glue and glue it into the front hole, to seal up the unused port permanently. Connect your skimmer pipe to the back hole, using a threaded PVC fitting that is either glued in place, or tightly installed with thread sealant. Run a straight pipe down to a 90 sweep elbow, or use two 45 fittings, to make a coupling connection to the skimmer pipe.
If your main drain pipe is tied into your skimmer, a float valve is used in the skimmer to control the amount of main drain water flow. For single hole combination skimmer plumbing info, used on older inground pools, see our blog post Inground Pool Skimmer Plumbing Diagrams.
Clogged Pool Skimmers
If you suspect that your skimmer line may be clogged, here are some useful tricks. Use a plumber's snake to try and break up the leaves & sticks (or whatever), or better yet, try a Drain King which attaches to the garden hose and puts high pressure in the line. Connect it to a garden hose and stick the Drain King into the pipe in front of the pump, facing towards the pool. Turn the valves to send all the water to the skimmer only (the clogged skimmer). Turn on the hose and the Drain King will expand inside the pipe to pressurize the line. Walk to the skimmer and hold a plug (or tennis ball) over the skimmer hole at the bottom, to build up pressure in the line for 3-5 seconds. Repeatedly building up and releasing pressure has a water hammer effect, and is a very effective way to clear a pipe. It is usually easier to push the clog back toward the skimmer, than to try to force it into the pump.
Leaking Pool Skimmers
If your plastic skimmer has pulled away from the concrete pool and is leaking, use an underwater Pool Putty or EZ Patch 22 silicone rubber, to patch it up temporarily and stop the leak. This is a very common pool leak source, between the plastic skimmer and the concrete pool. To verify a leaking skimmer, you can use a Dye test (with the pump off), and watch for dye leaving the pool. Small debris stuck in a small crack is also a good clue of a leak source. Skimmers can also crack from concrete expansion/heave. Here again, pool putty is used to repair cracked skimmer throats and wells. Some older skimmers may start leaking around the bottom plate, but this is rare. A liquid epoxy or PVC/ABS glue can be applied to a dry skimmer to seal up cracks in the skimmer bottom.
Vinyl pool skimmers attach to the wall of a vinyl pool with 4 round-head screws and a rubber or cork wall gasket between the skimmer and the backside of the wall. On the pool side of the wall, two paper gaskets are used, one under the liner and one on top of the liner. The plastic faceplate, visible on top of the liner, is screwed on tightly to sandwich the liner between the gaskets. Be sure to use the correct stainless steel faceplate screws for your skimmer, they are not all the same, and incorrect screws may not make a tight seal, and can damage the skimmer. A vinyl pool skimmer leaking from the pool side can usually be fixed by replacing the skimmer gaskets and the skimmer faceplate. Cracks in the body of the skimmer can be repaired with pool repair putty.
Pool Skimmer Parts
SKIMMER BASKETS: It is important to use the correct skimmer basket for the best skimmer and pump operation. If your basket floats when the pump shuts off, use a diver’s weight or a stone to hold it down. If your basket breaks under the strain of heavy leaves, try a Debris-Z or Skim Pro basket type. Some of the most popular skimmer baskets are available in heavy duty aftermarket versions. If your skimmer basket broke and became stuck down into the skimmer well, use larger pliers to yank it out, (likely breaking it in pieces). To vacuum directly into the skimmer basket (instead of into the pump basket), use a skimmer vac plate, sized to fit your skimmer model, as they are unique to each particular skimmer.
SKIMMER DIVERTERS: A skimmer diverter, or float valve is used to control the flow from the main drain on a combination skimmer (connected to the main drain). For single hole combination skimmers, a vertical pipe is used to cut off or reduce main drain flow, to allow for more skimming action, or for vacuuming the pool. For dual hole combination skimmers, the diverter is a flat device that sits on the bottom of the skimmer, with a flap to control the relative flow, or suction, from the main drain into the skimmer. Skimmer diverters or valves are unique to each particular skimmer; find your replacement in our skimmer parts department.
SKIMMER LIDS: They come with screws, useful in high winds. If your skimmer lids take flight in high winds, place a heavy stone on top, or bolt on a divers weight to the underside, or just use the screws. Also dangerous are broken lids. Replace a broken skimmer lid before someone steps on it and breaks an ankle! Skimmer lids or covers are unique to each particular skimmer; find your replacement in our skimmer parts department.
SKIMMER WEIRS: If your skimmer weir (the flapper door or gate) has broken loose, replace it with new. The weir is a very important skimmer part; it creates a small waterfall into the basket which speeds up water flow, drawing more debris in. The weir also helps to keep debris in the skimmer well when the pump shuts off. American Admiral skimmers can also use a Floating Weir design, which fits their specific tall basket design. Skimmer weirs are unique to each particular skimmer; find your replacement in our skimmer parts department, or use a spring loaded Universal skimmer weir of the correct width.