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MyWaterClub Product Support
Inline Coconut Carbon Filter, Stage 2 — 10″ × 2″
CAC-QC
Pre-carbon · Stage 2
This page covers where the filter goes, how to install it, when to change it, and the parts that fit it.
Is this your filter?
Check these against the filter in your hand. All four should match.
- ✓A white inline filter about 10″ long and 2″ across
- ✓The label says CAC · coconut shell carbon · pre-carbon, stage 2 (light blue)
- ✓1/4″ quick-connect ports at both ends and a flow arrow on the label
- ✓SKU / Reorder # CAC-QC on the label, and a QR code that opens this page
Stage 2 or last stage? Check the label
- CAC — stage 2, before the RO membrane (light blue label) — this page.
- PAC — post carbon, the last stage before the faucet (dark blue label). Same coconut carbon, labeled for its position so the two never get mixed up. PAC-QC post filter →
- SED — sediment, stage 1 (teal label). SED5-QC support page →
- Other inline filters (DI, mineral, alkaline, specialty) — see the full guide. Inline filter guide →
Specifications
| Model / SKU | CAC-QC |
| Media | Coconut-shell activated carbon |
| What it does | Reduces chlorine taste and odor, and protects the RO membrane from chlorine. It does not reduce fluoride, hardness or dissolved solids (TDS). |
| Position | Stage 2 — after the sediment filter, before the RO membrane |
| Size | 10″ × 2″ |
| Connection | 1/4″ quick connect · elbow adapters for 3/8″ OD tubing |
| Pressure / temperature | Max 90 PSI · 36–100°F, cold water only |
| Typical life | 12 months or 1,500 gallons (sooner if chlorine taste or odor returns) |
| Brand | MyWaterClub |
Reorder this filter
This filter · CAC-QC
Inline Coconut Carbon Filter, Stage 2
On MyWaterClub.com you choose 1/4″ or 3/8″ tubing, and the price per filter drops when you buy more.
Where it goes
CAC is the second stage: right after the sediment filter and before the RO membrane. It removes chlorine, which would damage the membrane.
| Your setup | Order of stages |
|---|---|
| Countertop RO | Faucet adapter → sediment (SED) → coconut carbon (CAC) → RO membrane → post carbon (PAC) → faucet |
| Countertop RO with DI | Faucet adapter → sediment (SED) → coconut carbon (CAC) → RO membrane → DI → post carbon (PAC) |
Placement rules
- Before the sediment filter — no. Grit would clog the carbon. Sediment always goes first.
- After the RO membrane — use the PAC post filter there, so each filter carries the label for its position.
- Mineral and alkaline filters always go after carbon, never before. Carbon removes minerals too.
- Hot water lines — not for hot water. Cold water only, 36–100°F.
Connections
Before you cut anything
- Check your tubing size. It is either 1/4″ OD or 3/8″ OD, usually printed on the tubing. Use the matching adapters. Never force 1/4″ tubing into a 3/8″ port, or the reverse.
- Water must flow the way the arrow on the label points.
- You need a towel and a small bowl or bucket. A tubing cutter helps if you need to trim tubing.
- 1/4″ tubing goes straight into the filter’s quick-connect ports. For 3/8″ tubing, add a 3/8″ elbow adapter to each port first.
- Cut the tubing square if you trim it. A cut off by about 15° or more will leak. The last inch should be round, smooth and free of scratches.
- Remove any blue C-clips from the adapters. A clip left in stops the tube from seating.
- Push the tube in until it stops, then pull gently to confirm it holds.
- Refit the blue C-clips on every quick-connect port.
To remove a tube later: turn off the water and release pressure, take off the C-clip, push the collar in toward the filter and pull the tube out while holding the collar.
Replacing it in a countertop RO
Follow your system’s manual. These steps are the same for most MyWaterClub countertop RO systems.
- Turn off the faucet and disconnect the faucet adapter. Open the RO tap to release pressure.
- Take photos of the system from both sides before you remove anything, so the tubing and the flow arrows are visible.
- Hold a towel under the filter, release both tubes and take out the old stage-2 filter.
- Put in the new CAC filter with the flow arrow pointing toward the RO membrane. Push both tubes in until they stop, tug to check, and refit the C-clips.
- Change the sediment filter (stage 1) at the same time — they share the same schedule.
- Reconnect the faucet adapter and turn the water on slowly. Check for leaks now, after 10 minutes, and the next day.
- Flush for at least 5 minutes before drinking the water. Grey water or a few black specks at first are carbon dust from a new filter — that’s normal.
- Write the install date on the label.
When to change your filter
| Filter | Typical interval | Change sooner if… |
|---|---|---|
| Coconut carbon (CAC), stage 2 | 12 months or 1,500 gallons |
Chlorine taste or odor comes back, or flow drops |
A TDS meter won’t tell you when to change a carbon filter — carbon doesn’t change dissolved solids. Go by the calendar and the taste. Changing on time also protects the RO membrane, which costs more to replace.
Parts that fit this filter
| Part | Notes |
|---|---|
| 5 micron sediment filter (SED5-QC) | Stage 1, goes right before this filter · change both together |
| Post carbon filter (PAC-QC) | Last stage, after the RO membrane |
| Countertop RO membranes | The stage after this filter |
| 1/4″ stem × 3/8″ quick-connect elbow, 2-pack | Adapters for 3/8″ tubing |
| Blue C-clips for 1/4″, 10-pack | Locks the tube in a 1/4″ port |
| 1/4″ OD tubing, white | If you need extra length · tubing cutter |
Common questions
| What you’re seeing | Most likely cause |
|---|---|
| Grey water or black specks right after a change | Carbon dust from a new filter. Flush for at least 5 minutes; it clears quickly. |
| Chlorine taste or odor came back | The carbon is used up. Replace the CAC filter, and the sediment filter with it. |
| Low flow | Filter installed backward, kinked tubing, or a clogged sediment filter before it. Check the arrows, the tubing and the stage-1 filter. |
| Drip at a quick-connect port | Tube not fully in, scratched or cut at an angle, or the C-clip was left in. Release, recut square, push it fully in and refit the clip. |
| TDS reading didn’t change after the new filter | Expected. Carbon doesn’t reduce dissolved solids — the RO membrane does that. |
Need help?
Contact us
Send a photo of the filter label and your system, and we’ll tell you where it goes
Call or text (858) 345-7345. Bought on Amazon? You can also reach us through Amazon: Your Orders › Contact seller.
Scope note: This is an activated carbon filter. It reduces chlorine taste and odor. It does not reduce fluoride, hardness or dissolved solids, and it is not a certified microbiological purifier. Use it on municipally treated or otherwise microbiologically safe water.
Please note: Filter life depends on your water quality, pressure and usage, so results vary from home to home. This product is not certified to treat water of unknown quality and is not a substitute for testing your water.