Astralpool O-Ring, Valve to Tank (Tank Lid) Green - ECA550, ECA650 Sand Filter - 7201750057 / SP7201750057

Astralpool O-Ring, Valve to Tank (Tank Lid) Green - ECA550, ECA650 Sand Filter - 7201750057

• We keep these physically in stock for fast shipping or local pick-up, unlike most drop-shipping websites.
• Shipped from VIC, NSW, WA, QLD

7201750057 is the genuine Astralpool O-ring that seals the multiport valve to the tank on ECA550 and ECA650 sand filters. On these top-mount filters the valve sits in the tank opening and acts as the lid, so the same green ring is listed as both the tank lid O-ring and the valve to tank O-ring. Astralpool's spare parts list calls it "O-ring - ECA models". The filters are also sold and listed as Hurlcon ECA and Astral ECA, and all of them take this ring.

If water weeps from the joint under the multiport valve while the clamp band is sound and correctly tightened, this O-ring is the usual cause.

The Clamp Band Rule (rev. ECA-1.1)

Astralpool ECA, EC, CA and Cantabric sand filters look alike but do not all take this O-ring. Check these before ordering:

1. Read the model label on the tank. Astralpool lists 7201750057 for ECA models: ECA550 and ECA650.
2. Look at how the multiport valve is held on. A clamp band around the neck of the tank and valve, tightened with a bolt, is the ECA arrangement this O-ring suits.
3. A large threaded lock ring screwed onto the top of the tank means a CA or Cantabric filter. Order the CA / Cantabric O-ring, 7211820060, instead.
4. A clamp band on a tank labelled EC550 or EC650 (no "A") means an EC filter. EC filters also use a clamp band, but Astralpool lists 7201750057 for ECA models, so send us a photo of the label before ordering.

This follows Astralpool's own installation instructions: ECA and EC valves are secured with a clamp band assembly around the neck of the filter and valve, while CA and Cantabric valves are held by a lock ring tightened by hand.

Worked Example

Say an ECA650 has just had its sand replaced and now weeps from the joint under the multiport valve. The tank label reads ECA650 and the valve is held on by a clamp band, so it takes 7201750057. With the pump off and pressure released, check two things before ordering: that the clamp band is not cracked or distorted, and that no sand is left on the sealing surface of the tank opening. If both are fine and the old ring is flattened, nicked or out of shape, this O-ring is the fix. If the band is cracked, you need clamp band 77730 as well.

Which Part Do I Need?

What This O-Ring Does Not Fit

• CA series (CA280, CA300, CA340, CA400) and Cantabric filters. Astralpool lists a separate O-ring for CA models, 7211820060, and these filters use a threaded lock ring rather than a clamp band.
• EC550 and EC650 (no "A" in the model). These also use a clamp band, but they are a different filter family that takes a different multiport valve, 76037. We have not confirmed this O-ring for EC filters, so send us a photo of your tank label before ordering.

Signs This O-Ring Has Failed

• Water weeping or spraying from the joint between the multiport valve and the top of the tank, with the clamp band sound and correctly tightened.
• A leak that starts after the valve has been lifted off, for example after a sand or glass media change.
• The old ring is flattened, split, hardened, stretched or has taken a permanent set.

When to Replace

• As soon as it shows any of the signs above.
• Any time the multiport valve is lifted off the tank for media replacement. It is cheap insurance while you are in there.

Fitting Notes

Based on Astralpool's installation instructions for ECA filters:

1. Turn the pump off and release system pressure before loosening the clamp band. The valve to tank joint is a pressure joint, and Astralpool rates ECA filters to a maximum operating pressure of 200 kPa.
2. Remove the clamp band and lift the multiport valve clear of the tank.
3. Remove the old O-ring and clean any sand or debris from the upper surface of the tank opening.
4. Lightly lubricate the new O-ring with a silicone-based lubricant and seat it in the cavity on the tank.
5. Lower the valve into the tank opening, making sure the O-ring stays in position.
6. Refit the clamp band and tighten it enough for good engagement. Astralpool notes it is not necessary to over-tighten.
7. Restart the pump and check the joint for leaks.

Specifications

• Part number: 7201750057
• Astralpool description: O-ring - ECA models
• Fits: Astralpool ECA550 and ECA650 sand (media) filters, also listed as Hurlcon ECA and Astral ECA
• Colour: green
• Position: seats in the cavity on the tank opening, under the multiport valve
• Function: valve to tank (tank lid) seal
• Valve held by: clamp band 77730
• Barcode: 9343609002619

Related ECA Filter Parts

• Multiport Valve 40mm, ECA550 / ECA650 - 76036
• Clamp Band ECA Complete - 77730
• Clamp Band Bolt, Nut & Allen Key Kit - 78399
• Lateral Hub, ECA & CA Media Filter - 77712
• Laterals 175mm, Pair - 77756
• Drain Plug Cap, CA / ECA - 77717
• Component Bag 40mm ECA Multiport - 78355

Frequently Asked Questions

Is this the tank lid O-ring or the valve to tank O-ring?
Both. On the top-mount ECA550 and ECA650 the multiport valve sits in the tank opening and acts as the lid, so the tank lid O-ring and the valve to tank O-ring are the same seal. Astralpool lists it as part 7201750057, O-ring - ECA models.

Will this O-ring fit a CA or Cantabric filter?
No. CA and Cantabric filters use O-ring 7211820060. This one suits the ECA series.

Does this fit a Hurlcon ECA filter?
Yes, if the tank label reads ECA550 or ECA650. These filters are also sold and listed as Hurlcon ECA and Astral ECA, and all of them use this O-ring.

How do I tell an ECA filter from a CA or EC filter?
Read the model label on the tank first. Then look at how the multiport valve is held on: ECA filters use a clamp band around the joint between valve and tank, while CA filters use a threaded lock ring. EC filters (EC550, EC650) also use a clamp band, so the label is what separates ECA from EC.

My ECA filter leaks where the valve meets the tank. Do I need a new clamp band?
Only if the band is cracked, distorted or will no longer tighten. If the band is sound but the bolt is seized or missing, the bolt, nut and Allen key kit 78399 is the fix. If the band and bolt are both sound, this O-ring is the more likely cause.

Why does my filter leak after a sand change?
Check two things first: sand or debris left on the sealing surface of the tank opening, and whether the O-ring moved out of its cavity when the valve was lowered. Astralpool's instructions are to clean the tank opening and make sure the O-ring stays in position as the valve goes on. If the ring is flattened or damaged, replace it.

Should I lubricate the O-ring on fitting?
Use a silicone-based lubricant suitable for pool equipment. Do not use petroleum-based grease, which degrades the rubber.

How tight should the clamp band be?
Astralpool's instructions are to tighten it enough for good engagement, and they note it is not necessary to over-tighten. Over-tightening distorts the band and will not cure a leaking seal.

Is this a genuine Astralpool part?
Yes. Heater and Spa Parts is an authorised Fluidra dealer and warranty agent, and this is the genuine Astralpool O-ring, part 7201750057.

Common search terms: 7201750057, Astralpool ECA O-ring, Astral ECA filter O-ring, Hurlcon ECA valve to tank O-ring, ECA650 lid O-ring, ECA550 lid O-ring, ECA sand filter tank O-ring, Astral media filter valve to tank O-ring, green O-ring Astral sand filter, ECA filter lid seal, WWDG SpaPro.

Manufacturer Catalogues, Diagrams & Part Numbers: Need exploded views, spare part numbers, product numbers, diagrams, or more product information? See the manufacturer catalogues below.

• Astralpool Catalogue 2026 | Zodiac Catalogue 2026

Important Before Ordering: Please ensure you order correctly. Confirm this product is suitable before ordering. Use the catalogues above, seek professional assistance, or contact us with photos of your existing part, model details, serial numbers, and any labels.

As with all products, these must be diagnosed and fitted by a qualified and experienced person.