Pool Skimmer Guide: How It Works, Baskets & Fixes
How a pool skimmer works, from the weir door to the basket. Cleaning tips, skimmer socks, and fixes for weak suction on SEQ fibreglass pools.
A pool skimmer is the built-in surface cleaner working every time your pump runs. It pulls the top thin layer of water off the pool and traps the floating rubbish in it before that rubbish waterlogs and sinks. Leaves, petals, dead insects, twigs, pollen, sunscreen and body oils all ride on the surface, and a skimmer catches them there where they are easy to remove, instead of on the pool floor where they stain the gelcoat and feed algae.
On a fibreglass pool the skimmer is moulded straight into the shell wall, so it sits flush with the interior. Understanding how yours works, and how to keep it drawing properly, is the difference between a five-minute weekly job and a green pool by Sunday.
How does a pool skimmer work?
A pool skimmer works by pulling surface water through a floating weir door into a basket, then down to the pump. Because the skimmer opening sits right at the waterline, the pump can only draw the very top skin of the water — exactly where floating debris and oils collect. That surface tension effect is why a correctly set skimmer keeps a large area of water clear from one small inlet.
Here is the path a single leaf takes:
| Stage | What it does |
|---|---|
| Weir door | A hinged flap at the mouth. It floats up and down with the water level and creates a fast, thin overflow so debris is sucked in and can't float back out |
| Skimmer basket | Catches leaves and debris so they never reach the pump. This is the part you empty |
| Suction line | Carries the pre-filtered water from the skimmer down to the pump |
| Equaliser line | A lower port that lets the pump keep drawing water if the surface drops below the weir |
The weir door is the part most people ignore, and it does the real work. It self-adjusts to the water level and accelerates the surface flow into the throat of the skimmer. When that little flap is stuck open, jammed by a stone, or missing entirely, debris the skimmer already caught can wash straight back into the pool the moment the pump stops. If your weir isn't swinging freely, replace it — they're a cheap moulded part.
Where the skimmer sits and why it matters
A skimmer works best positioned so the prevailing wind pushes floating debris towards it. On most SEQ blocks the afternoon sea breeze and summer storms drive leaves to one end of the pool, and a well-placed skimmer mouth on that side keeps a large surface area pristine from a single inlet. If your pool has two skimmers, the pump draws from both and you get faster surface turnover.
The return jets matter too. Aim them slightly across and towards the surface, away from the skimmer, so they create a gentle circular current that walks floating debris around to the skimmer mouth. Point them straight down and the surface goes still — debris just sits there.
Cleaning the skimmer basket
Empty the skimmer basket at least weekly, and every few days in autumn leaf-drop or after a summer storm. A basket packed with leaves is the single most common cause of weak circulation, because the pump is starved of water long before your filter is even dirty.
The routine takes a minute:
- Switch the pump off at the equipment pad. Never pull a basket with the pump running — you'll suck debris straight into the suction line.
- Lift the deck lid and pull the basket straight up.
- Tip it out, and pick off any leaves plastered to the sides.
- Check the weir door swings freely and the basket isn't cracked. A split basket lets leaves through to jam the pump impeller.
- Drop it back in seated flat, replace the lid, restart the pump.
During peak leaf and pollen season, letting debris rot in the basket doesn't just strain the pump — it leaches tannins and phosphates back into the water, which is exactly what your chlorine has to fight. Regular basket emptying is one of the cheapest things you can do for water clarity. It sits alongside a few other habits in a solid fibreglass pool maintenance routine.
Skimmer socks: worth it or not?
A skimmer sock is a fine mesh sleeve that stretches over the basket and catches the tiny stuff the basket lets through — pollen, fine silt, sunscreen oils and the yellow dust that coats everything in a SEQ spring. They keep your filter cleaner for longer and noticeably improve water sparkle.
The trade-off is flow. A sock clogs faster than a bare basket, so during heavy pollen you may need to rinse or swap it every couple of days. When one blinds over, suction drops away and you'll wonder why the pool looks tired. Use them, but check them often. They're inexpensive and machine-washable, so a two-pack lasts a season.
Troubleshooting weak skimmer suction
Weak or lost skimmer suction almost always traces back to a starved pump or an air leak, not a broken pump. Work through the cheap, common causes before assuming the worst:
| Symptom | Likely cause | Fix |
|---|---|---|
| Weir barely moving, poor surface pull | Full skimmer basket or blinded sock | Empty basket, rinse or replace the sock |
| Air bubbles from the return jets | Water level below the weir, drawing air | Top the pool up to mid-skimmer |
| Suction fine at pump, none at skimmer | Diverter valve set to main drain | Rebalance the valve towards the skimmer |
| Pump loud, low water in the strainer basket | Air leak on the suction side | Check the pump lid o-ring and its seating |
| Whole system gutless | Dirty filter raising back-pressure | Backwash or clean the cartridge |
The water level one catches everyone. Your skimmer needs the surface sitting roughly at the middle of its mouth — around a third to halfway up the opening. Queensland summers evaporate a pool fast, and a hot week of splash-out can drop the level below the weir. Once that happens the pump gulps air, loses prime, and can run dry. Keep the level up, especially through January and February.
What the equaliser line is for
The equaliser line is a second, lower port inside the skimmer that acts as a backup water source. If evaporation or heavy use drops the surface below the weir, the equaliser lets the pump keep drawing from below instead of sucking air. It's a safety valve against a dry pump — but it isn't a substitute for keeping the water topped up, because water drawn through the equaliser bypasses surface skimming entirely.
Fibreglass-specific notes
On a fibreglass shell the skimmer is part of the moulded structure, so there's no concrete rendering to crack or leak around it — one less failure point than a concrete pool. The smooth gelcoat interior also means debris slides towards the skimmer rather than catching on a rough surface, so surface skimming is genuinely more effective.
Two things to watch. First, never let the water sit below the skimmer for long during construction handover or a holiday — a fibreglass shell in an empty or low state on wet SEQ clay can be affected by ground water pressure, so keep it filled. Second, be gentle with the moulded weir and lid seats; they're gelcoat, and a dropped pool pole chips them. A telescopic pole with a soft leaf rake and a good vacuum head handles the debris the skimmer can't reach — the right pool tools for inground pools make the weekly clean far quicker.
Robotic surface skimmers
A robotic surface skimmer is a floating, solar- or battery-powered unit that roams the pool collecting debris off the top, independent of your plumbed skimmer. They're good at clearing leaves before anyone swims, and they take load off the fixed skimmer during autumn drop. Think of one as a helper, not a replacement — your built-in skimmer, weir and basket are still doing the plumbed circulation work. Modern setups also pair the skimmer circuit with automatic chlorinators and water-level controls that keep dosing and top-up steady without you thinking about it.
When your pool is running the way it should, the skimmer is invisible — it just quietly keeps the surface clean. It only becomes a job when the basket's full or the level's dropped, and both take a minute to fix.
If you're planning a new fibreglass pool and want the skimmer placement right for your block, book a free site visit and we'll measure up on site.
FAQs
How often should I empty my pool skimmer basket?
At least once a week, and every two to three days during autumn leaf-fall, heavy pollen, or after a summer storm. A full basket starves the pump and drops your circulation long before the filter itself is dirty, so it's the first thing to check when the pool looks off.
Why has my pool skimmer lost suction?
The most common cause is a low water level letting the skimmer draw air, followed by a full basket or a clogged skimmer sock. Check those first: top the pool to the middle of the skimmer mouth, empty the basket, and rinse the sock before assuming a pump or plumbing fault.
What is the weir door on a pool skimmer?
The weir is the hinged flap at the skimmer mouth. It floats with the water level and accelerates the surface flow so debris is pulled in and can't wash back out when the pump stops. If it's stuck or missing, caught leaves escape back into the pool — it's a cheap part to replace.
Should I use a skimmer sock?
Yes, if you want clearer water and a cleaner filter, especially through SEQ pollen season. A sock traps fine silt and oils the basket misses. Just check it every couple of days during heavy pollen, because it clogs faster than a bare basket and will choke your suction when it blinds over.
What water level should my skimmer sit at?
Keep the surface at roughly the middle of the skimmer opening — about a third to halfway up the mouth. Too low and the pump draws air and can run dry; too high and the weir can't skim properly. Queensland summers evaporate a pool quickly, so top up regularly in the hot months.
