Pool Filter Leaking From the Bottom? When to Replace Just the Tank Body (Pentair 178560)

A puddle under the filter is easy to shrug off for a week or two. Then the pad never dries, the water level drops faster than it should, and you start wondering how bad it really is. Nine times out of ten the leak is a gasket or a drain plug. The tenth time, the plastic housing itself has failed, and on a Pentair Clean & Clear that usually means the lower half of the tank.

The good news is you don't always have to buy a whole new filter. Pentair sells the bottom section by itself. Part number 178560 is the tank bottom for Clean & Clear cartridge filters in the 150 and 200 square foot sizes.

Why is my pool filter leaking from the bottom?

Most bottom leaks come from one of four spots, and only one of them requires a new tank. Work through them in order before you spend money.

• The drain plug or drain cap. The o-ring behind it dries out and shrinks. This is the cheapest fix by far.
• The bulkhead where the inlet and outlet pipes enter the tank. Look for water tracking down the pipe or beading on the fitting.
• The clamp band and tank o-ring in the middle seam. Water running down the outside of the tank often lands at the bottom and looks like a bottom leak.
• A crack in the tank body itself. Usually a hairline split near the base or around the drain boss.

Dry the whole filter with a towel, run the pump, and watch for two or three minutes. Whatever gets wet first is your leak. Doing this before ordering parts saves a lot of guessing.

How do you know the tank is cracked and not just a gasket?

A cracked tank leaks under pressure and stops when the pump shuts off. A gasket leak often keeps weeping for a while after shutdown. That's the quickest tell.

The other sign is location. Gasket leaks show up at a joint. Tank cracks show up in the middle of a smooth surface, and if you look closely with the tank dry you can often see a thin white line in the plastic. Freeze damage is the usual cause, followed by years of UV exposure and someone overtightening the clamp band. If you find a crack, don't try to patch it. Filter tanks hold real pressure and epoxy repairs tend to let go at the worst possible moment.

What does the Pentair 178560 fit?

The 178560 is the tank bottom for Clean & Clear cartridge filters rated at 150 and 200 square feet. Before you order, check the label on your filter and confirm the square footage, since the smaller and larger Clean & Clear models use different bottoms.

If your filter is a Clean & Clear Plus or an FNS Plus, the tank bottom is a different part number. Same idea, different housing. Send us your model number if you're not sure which one you have and we'll match it.

Is replacing the tank bottom cheaper than a new filter?

Usually yes. A new Clean & Clear filter runs several times the cost of the tank bottom, and you would be throwing away a perfectly good top half, clamp, cartridge, and plumbing connections.

The math changes if the filter is old and the top is also chalky and brittle, or if the cartridges are due for replacement anyway. At that point you're rebuilding most of the filter one piece at a time, and a complete unit starts to make sense. A rough rule: if the housing is under ten years old and only the bottom is bad, replace the bottom.

How to replace the tank bottom

• Turn off the pump at the breaker and open the air relief valve on top of the filter.
• Pull the drain plug and let the tank empty completely.
• Loosen the clamp band and lift the top half off. Set the cartridge aside where it won't get stepped on.
• Disconnect the plumbing at the unions. If your filter is hard piped with no unions, this is a good time to add them.
• Move the internal parts over to the new 178560 bottom exactly as they came out.
• Lubricate the tank o-ring with silicone grease, reassemble, and snug the clamp band evenly. Do not crank it down.
• Prime the pump, open the air relief until water sprays out, then close it and check for leaks.

Plan on an hour or two. The only part that tends to slow people down is the plumbing, so have couplings and glue on hand just in case.

Parts worth replacing at the same time

While the filter is apart, replace the tank o-ring, the drain plug o-ring, and the air relief valve if it's stiff or weeping. These are inexpensive and it's frustrating to reassemble everything only to find a second leak. If the cartridges are more than a few seasons old and pressure climbs quickly after cleaning, swap those too.

Pentair | 178560 | Clean & Clear Filter Tank Bottom | 150/200 sf Cartridge Filter

$320.00

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