Description
A spa or a small above-ground pool does not need a big filter tank, but it does need enough cartridge area to go more than a week between cleanings. The Hayward C225 gives you 25 sq ft in a tank under 18 inches tall, on 1-1/2″ FIP plumbing, with a single knob holding the head down so you can pull the cartridge without tools.
This is the right size if
- Your water volume is under 4,500 gallons: That is a full turnover in 8 hours. Up to 5,625 gallons if you run 10 hours.
- You are filtering a spa, hot tub or small above-ground pool: The tank is built for that duty.
- Your plumbing is 1-1/2″: Inlet and outlet are 1-1/2″ FIP.
- You have 18 inches of side clearance: Needed to lift the cartridge straight out.
What you get in the box
- Filter tank and head: With pressure gauge and manual air relief already fitted.
- One CX225RE cartridge: Installed and ready to run.
- Locking knob: No clamp band, no bolts.
Note: The pump is not included — this is the filter alone. Unions and plumbing are separate. Hayward builds a factory filter-and-pump combo under its own model number if you need the pair.
Keeping it running
- Cartridge: CX225RE, or CX225XREM for the Microban-coated version.
- Tank o-ring: CX120D — the part that leaks first if it dries out.
- Drain: 1/2″ FIP at the base, takes a standard spigot valve for winterising or draining an elevated spa.
Frequently Asked Questions
My spa water is cloudy and the filter is only a few months old. Is the filter too small?
Usually not. Cloudiness in a small body of water is more often chemistry or a cartridge that needs rinsing than undersized filter area. Note your clean starting pressure when you fit a new cartridge — if the gauge has climbed well above it, the element is loaded and needs cleaning, not replacing.
Can I use this on an in-ground pool?
Only a very small one. At 4,500 gallons per 8-hour turnover it is sized for spas and small above-ground pools. A typical in-ground pool will not turn over properly on this tank.
How often will I be cleaning the cartridge?
It depends entirely on bather load and how much debris gets in. Go by the pressure gauge rather than the calendar — record the reading with a fresh cartridge and clean when it rises noticeably.
Do I need to replace the cartridge or can I just rinse it?
Rinse it until it stops recovering. When a cleaned cartridge no longer brings the pressure back down near its original reading, the pleats are done and it is time for a new CX225RE.
Will a bigger Star-Clear cartridge fit this tank?
No. The C250, C500, C750 and C1200 use different elements in different tanks. The C225 takes the CX225RE only.
Why is there a drain on the bottom?
It is a 1/2″ FIP port for draining the tank — useful on elevated spas and tubs, and for winterising. It accepts a standard spigot valve if you want to leave one fitted.
