When the sand is due
Neither the Hayward ProSeries manual nor the Pentair Triton guide prints a sand-change interval. The five-to-seven-year figure you will hear is a trade rule of thumb, useful for budgeting and not much else. What the manuals do give you is a test, and it runs off the pressure gauge.
Pentair’s version: if the starting pressure after a backwash sits 4 to 6 psi above the filter’s normal clean reading, chemically clean the bed. If the bed is plugged and the runs between backwashes keep getting shorter, scoop out the top inch, top it up with new sand and clean the rest. Hayward says the same in fewer words: check the sand surface for crusting or caking and remove an inch if you need to.
The decision in one line
Clean first. If a cleaned bed still will not come back near its clean reading, or water stays dull at normal pressure, the sand is finished. The cleaning guide has the symptom table for a worn bed versus a dirty one, and the pressure gauge guide explains the readings.
How much sand your tank takes
Read it off the label on the tank or the owner’s manual for your exact model number. There is no universal chart, because tank diameter, internals and the maker’s freeboard all change the answer. Here are two makers’ published tables as examples of what you are looking for, not as a substitute for your own.
Hayward ProSeries (top mount)
| Model | Sand, lb |
|---|---|
| S166T | 100 |
| S180T | 150 |
| S210T | 200 |
| S220T | 250 |
| S244T | 300 |
| S270T | 350 |
| S310T2 | 500 |
| S360T2 | 700 |
Sand level at least 10 in. below the top, every model.
Pentair Triton II (side mount)
| Model | All sand, lb | Freeboard |
|---|---|---|
| TR40 | 175 | 8 1/4 in. |
| TR50 | 225 | 9 3/4 in. |
| TR60 | 325 | 10 1/2 in. |
| TR100 | 600 | 11 1/4 in. |
| TR140 | 925 | 13 1/2 in. |
Pentair: freeboard is the variable that matters; the weight is a reference.
Notice how Pentair frames it: sand density varies, so the weight is a reference and the freeboard (the gap between the top of the bed and the top of the tank) is what you fill to. Pentair also lists a pea gravel and sand option for every Triton model (for example 50 lb of gravel plus 275 lb of sand in a TR60). If your old bed had a gravel layer at the bottom, the manual is telling you to put one back.
Silica, glass or zeolite
Both manuals specify No. 20 silica sand and nothing else. Glass and zeolite media are sold as drop-in upgrades, and their makers make real claims for them, but those are the makers’ claims rather than the filter manufacturer’s.
| Media | What the documents say | Who says it |
|---|---|---|
| No. 20 silica sand | The only media both manuals name. Hayward gives 0.45–0.55 mm grains; Pentair gives 0.018–0.020 in. with a uniformity coefficient no higher than 1.75. | Hayward IS210TS, Pentair P/N 154901 |
| Glass (e.g. AFM) | Crushed soda-lime-silica glass. The maker claims its Grade 1 removes 95% of particles over 1 µm and a life cycle of more than 10 years. | Dryden Aqua, maker's claim |
| Zeolite (e.g. ZeoBest) | A natural mineral at half the weight of filter sand. The maker claims 3–5 micron filtration, says it lasts as long as sand, and says to follow the filter maker's fill specs. | NFM, maker's claim |
If you switch, do it with the media maker’s fill instructions in one hand and your filter’s freeboard in the other. Zeolite weighs about half what sand does, so filling a ProSeries 24 to “300 lb” of it would over-fill the tank. Fill to the line, not the number on the bag. Whatever you choose, it does not fix an over-driven filter. Check the flow per square foot with the turnover calculator before you blame the media.
The change, step by step
A sand filter is a pressure vessel
Pump off and automatic controls off, air bleeder open, and wait until the pressure is gone before you touch a clamp or closure. Pentair’s guide warns that a closure fitted wrong or started with air inside can separate from the tank.
- Isolate and drain. Pump off at the breaker. If the filter sits below the waterline, close the suction and return valves first. Then pull the drain cap or plug at the base of the tank. Pentair warns its tanks drain very slowly.
- Take the top off. On a top-mount tank, loosen the flange clamp and lift the multiport valve straight up off the standpipe. On a side-mount Triton, take off the closure and swing the diffuser out of the way.
- Cap the standpipe. Tape or plug its open top so nothing falls in. Hayward ships a sand shield for this, and you will need it again when you refill.
- Get the old sand out. Scoop it out by hand or use a wet/dry vac. Pentair also lets you flush it out through the sand drain with a hose, or use its own sand vacuum. Keep the standpipe upright the whole time, because levering it sideways is how laterals snap.
- Inspect the laterals. With the tank empty, look at every finger. Pentair’s troubleshooting table traces sand in the pool to a broken lateral, and its guide says to replace any broken or loose ones before you refill. Hayward sells ProSeries laterals by tank size (the 24 and 27 in. tanks share one 10-pack).
- Rinse the tank and re-seat the internals. Hayward: standpipe secure in the bottom hub, centred, laterals in the down position.
- Water first. Both manuals say to fill the tank about half full with water before any media goes in, to cushion the laterals.
- Pour slowly. Gravel first if your model uses it, then sand, poured slowly enough that it does not hit the laterals hard. Keep the standpipe centred and stop at the freeboard line.
- Clean the seal faces. Wash all sand off the threads or flange, take the shield off the standpipe, and clean and lightly grease the O-ring with silicone lubricant. Dirt on the sealing surface is one of the causes Pentair lists for a leak at the closure.
- Reassemble. Refit the valve or closure as the manual says. Pentair’s threaded closures go on at least hand tight plus a quarter turn, using the plastic wrench supplied, and never with the pump running.
Restarting on a fresh bed
New sand carries fines, so the first run goes to waste, not to the pool. Hayward: start in BACKWASH with every suction and return valve open, run at least two minutes once the flow out of the waste line is steady, then RINSE for half a minute to a minute until the sight glass is clear, then FILTER. Pentair: backwash until the waste water is as clear as the pool water. Shipping can grind the sand, so that may take longer than a normal backwash.
Pump off between every valve move
Both makers say to stop the pump before you change the valve position. If your filter has a manual air bleeder, open it and stand clear each time you start the pump, then close it when a steady stream of water comes out. The full sequence is in the backwash guide.
Then do the step that makes the next five years easier. Once it is back on FILTER, read the gauge and write that number on the tank. That is your new clean pressure, and every future backwash call is measured against it. Hayward uses a rise of 8 to 10 psi; Pentair uses 10. If the pool was cloudy before the change, give the new bed a day before you judge it, and work through cloudy pool water if it is still dull after that.