iSpring RCC7 Replacement Filters: Which Cartridge Fits Each Stage of the RCC7, RCC7AK and RCC7AK-UV
iSpring RCC7 stages take FP15, FG15, FC15 (10 in, 5 micron) every 6 months, the MC7 membrane every 2-3 years, FT15 yearly. F7-GAC fits RCC7, F9K fits RCC7AK.
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Short answer
The iSpring RCC7, RCC7AK and RCC7AK-UV share the same first five stages, and iSpring’s RO owner’s manual (Ver. 02/2021) names the part for each: FP15 5 micron sediment in stage 1, FG15 5 micron granulated carbon in stage 2, FC15 5 micron carbon block in stage 3, all 10 in cartridges in the standard housings, then the MC7 thin-film composite membrane in stage 4 and the FT15 inline post carbon in stage 5. The RCC7AK adds the FA15 alkaline filter as stage 6; the RCC7AK-UV adds a UV lamp as stage 7. The manual’s schedule is 6 months for stages 1 to 3, 2 to 3 years for the membrane at 90 percent or better TDS rejection, 12 months for the FT15 and 6 months for the FA15. The annual pack differs by model: F7-GAC for the RCC7, F9K for the RCC7AK, F10KU for the RCC7AK-UV. The spec that must match is pack to model: the F9K carries an alkaline filter the RCC7 has no stage for.
What fits
Plain RCC7 or RCC7P: the annual set
iSpring F7-GAC 1-year pack
7 pieces per the listing title; the manual's 1-year pack for RCC7 and RCC7P; no membrane
RCC7AK or RCC7P-AK: the annual set with the FA15
iSpring F9K 1-year pack
No membrane included; the manual's 1-year pack for the six-stage alkaline models. Piece count not confirmed on the listing this session
RCC7AK-UV: the annual set with the UV lamp
iSpring F10KU 1-year pack
10 pieces per the listing title, alkaline and UV filters included, no membrane; the manual's 1-year pack for the RCC7AK-UV
Stage 4 on every model, on a 2-3 year cycle
iSpring Greatwell MC7 membrane
75 GPD per the listing title; the manual's stage 4 part, 0.0001 micron thin-film composite; sold separately from the annual packs
The number people get wrong is not the micron rating, which is 5 on all three pre-filters, but the pack: F9K is the RCC7AK’s annual set, and it is the wrong buy for a plain RCC7.
Which cartridges fit the RCC7, RCC7AK and RCC7AK-UV?
The manual’s glossary fixes the stage order and the part numbers below, and its filter pack chart fixes which pack fits which model. Stages 1 to 5 are identical across the three; only the add-on stages differ. The manual’s certification footnote covers exactly these three models: RCC7, RCC7AK and RCC7AK-UV are tested and certified by NSF International against NSF/ANSI 58 for TDS reduction, and the RCC7D, RCC7U, RCC1UP and RCC1UP-AK that share the manual are not.
| Stage | Function (manual’s glossary) | Part | Size and rating | Fits |
|---|---|---|---|---|
| 1 | Polypropylene sediment filter | FP15 | 10 in, 5 micron | All three models |
| 2 | Granulated activated carbon (GAC) | FG15 | 10 in, 5 micron | All three models |
| 3 | CTO carbon block | FC15 | 10 in, 5 micron | All three models |
| 4 | Thin-film composite (TFC) RO membrane | MC7 | 0.0001 micron; 75 GPD per the listing titles, no dimension in the manual | All three models |
| 5 | Inline post carbon, final polishing | FT15 | Inline; quick-connect on the tubing side, threaded (Teflon tape) where the fitting screws onto the cartridge | All three models |
| 6 | Alkaline remineralization filter | FA15 | Inline | RCC7AK and RCC7AK-UV only |
| 7 | UV lamp | Not named in the shared manual | Included in the F10KU pack per the listing title | RCC7AK-UV only |
iSpring sells the cartridges as timed packs. The manual’s chart gives the pack per model; the piece counts come from each pack’s Amazon listing title, unverified against an opened product page this session, and the manual itself does not itemise a pack. The F9K listing title does not state a piece count at all.
| System model | 1-year pack | 2-year pack | 3-year pack |
|---|---|---|---|
| RCC7, RCC7P | F7-GAC (7 pieces) | F15-75 | F22-75 |
| RCC7AK, RCC7P-AK | F9K (no membrane; piece count not confirmed) | F19K75 (19 pieces) | F28K75 (28 pieces) |
| RCC7AK-UV | F10KU (10 pieces, with UV and alkaline filters, no membrane) | F21KU75 | F31KU75 (31 pieces) |
The F9K and F10KU listing titles say no membrane; the F31KU75 listing specifies one, so the membrane arrives with the longer packs. The MC7 is also sold on its own.
Two production figures circulate for these systems and they measure different things. The manual’s operating conditions table gives a daily production rate of 21.04 gpd and an efficiency rating of 12.60 percent, both verified by testing to NSF/ANSI 58, Section 6.7, under conditions that approximate typical daily use. The 75 GPD in the membrane and pack names is the membrane’s nominal rating from the listings. The same table sets feed limits of 750 ppm TDS, 2.0 mg/L chlorine, 2000 mg/L hardness at pH 6.9, pH 2.0 to 11.0, 45 to 70 psi and 40 to 100 F.
What else fits the same housings?
The manual describes stages 1 to 3 as 10 in cartridges and prints no diameter, so the fit spec you have is the length plus the standard-housing format: the housing O-ring (part ORF) is 3 5/8 in O.D. Any 10 in cartridge sold for standard housings fits the thread and the length; what changes is the rating.
| Alternative | Same size? | What differs from the iSpring part |
|---|---|---|
| Any standard 10 in sediment or carbon cartridge | 10 in length, yes; diameter unpublished by iSpring | Micron rating and capacity are the seller’s figures. iSpring rates its own three at 5 micron; a finer cartridge fits and loads sooner |
| Generic 75 GPD membrane (listed as compatible with RCC7, RCC7AK, RCC7P, RCC7P-AK, RCC7D, RCC7U and several APEC models) | Listings disagree: one MC7 listing says 11.75 x 1.75 in, the F31KU75 listing says 9 3/4 x 2 7/8 in for the membrane; the manual gives no dimension | Compatibility is the seller’s claim, not iSpring’s. The manual states the RO component should be replaced with one of identical specifications as defined by the manufacturer to keep the certified efficiency and reduction performance |
| Inline post carbon and alkaline filters from other brands | Inline; quick-connect tubing, threaded cartridge ends | The manual’s FT15 procedure has the fitting screw onto the cartridge ends wrapped with Teflon tape, so a replacement needs the same thread on that joint; no thread size is printed |
If the housings you are refilling are 20 x 4.5 in Big Blue, you are on the wrong page: those are the whole-house units, and the iSpring WGB32B parts page carries their cartridges.
How often do they need replacing?
The manual’s maintenance section gives one figure per stage and the condition that shortens it.
| Stage | Manual’s interval | Shortens when |
|---|---|---|
| 1 to 3 pre-filters | Every 6 months | Water flow or quality drops; the interval depends on usage and source water |
| 4 MC7 membrane | Every 2 to 3 years | TDS starts rising; check monthly, rejection should stay at 90 percent or more |
| 5 FT15 post carbon | Every 12 months | Not stated |
| 6 FA15 alkaline | Every 6 months in the manual text; its schedule chart prints 6 to 12 months | Not stated |
| Membrane housing O-ring (ORM) | Every 3 years | Leaks at the membrane cap |
The rejection check is arithmetic the manual spells out: divide RO water TDS by tap water TDS and subtract from 1, so 20 over 200 gives 0.1 and a 90 percent rejection rate. The manual ties membrane life to pre-filter discipline: changing stages 1 to 3 on schedule is what protects the membrane from chlorine and other damaging contaminants.
Which pack to buy
The iSpring packs are the only sets the manual names, and the manual is also the only document that prints a micron rating for them: no capacity in gallons, no pressure drop, and no membrane dimension appear anywhere in it, so a cross-fit cannot be checked against a published spec, only against the seller’s compatibility list. If you own a plain RCC7, buy F7-GAC and skip the F9K , which carries an FA15 your system has no stage for. If you own an RCC7AK, buy F9K , or F19K75 when the membrane is due. If you own an RCC7AK-UV, only F10KU carries the UV lamp. Buy no pack at all until you have a TDS meter reading: a rising number with fresh pre-filters points at the membrane, which none of the 1-year packs include.
Frequently asked questions
Which iSpring filter goes in which stage of the RCC7?
The iSpring RO owner's manual (Ver. 02/2021) puts the FP15 5 micron polypropylene sediment filter in stage 1, the FG15 5 micron granulated activated carbon in stage 2, the FC15 5 micron carbon block in stage 3, the MC7 thin-film composite membrane in stage 4 and the FT15 inline post carbon in stage 5. All three pre-filters are 10 in cartridges in the standard housings.
Does the F9K filter pack fit a plain iSpring RCC7?
No. The manual's filter pack chart lists F9K as the 1-year pack for the RCC7AK and RCC7P-AK, the six-stage models with the FA15 alkaline filter. The plain five-stage RCC7 and RCC7P use F7-GAC for one year, F15-75 for two years and F22-75 for three years. The RCC7AK-UV, with a seventh UV stage, uses F10KU, F21KU75 and F31KU75.
How often does the iSpring RCC7 membrane need replacing?
iSpring's manual says the MC7 membrane typically lasts 2 to 3 years, or less if the TDS reading starts rising. It asks for a monthly TDS check and a rejection rate of 90 percent or more, worked out as 1 minus RO water TDS divided by tap water TDS. Changing the three pre-filters on the 6 month schedule is what protects the membrane from chlorine.
Can a generic 75 GPD membrane replace the iSpring MC7?
Third-party listings claim compatibility with the RCC7, RCC7AK, RCC7P and RCC7D, but the manual publishes no membrane dimension, and two listings disagree on the size (11.75 x 1.75 in against 9 3/4 x 2 7/8 in). The manual also states the RO component should be replaced with one of identical specifications as defined by the manufacturer, so a generic membrane is at your own judgement.
What else should be replaced when changing the RCC7 membrane?
The manual recommends a new membrane housing O-ring (part ORM, 2 1/2 in O.D.) every 3 years, because an expired or dried-out O-ring is a leak point. The stage 1 to 3 housings use the 3 5/8 in O.D. ORF O-ring. After a membrane change the manual has you check the TDS rejection rate settles at 90 percent or better.
