Lan Shan S2S Quick Change Replacement Filters | LSRO-301A 301B 3-Stage RO 7 inch

Genuine Lan Shan S2S series 7-inch quick-change (twist-in) replacement cartridges for the compact Lan Shan LSRO-301 reverse osmosis system, the three-stage unit with the slide-open case and built-in 3 litre tank. Choose a single cartridge or a pack from the drop-down menu.

Suits these Lan Shan systems

• LSRO-301A countertop: booster pump, front knob-switch faucet (blue, yellow or green knob), micro-computer with TDS display, leak detection and filter reminders
• LSRO-301B / LSRO-301BN under sink: same three-stage unit without the booster pump, supplied with an external PV803 faucet

Both are three-stage systems using the same short S2S cartridges in this order: S2S-05 sediment, S2S-34 granular carbon, S2S-RO50 membrane. The cabinet is 150 mm wide, 410 mm deep and 390 mm high, with a 3 litre food-grade cleanable tank inside. Lan Shan lists the S2S range as made for the 301; it is not fitted to the 801, 802, 302 or EQ5A, which take the longer S2 cartridge.

Sold in Australia under other names

The LSRO-301A and LSRO-301BN are WaterMark certified for Australia and are also imported and rebadged. The one to know about:

• Micron Water Filters RO-301B (3 Stage RO Undersink System, 3 L internal tank), sold through plumbing suppliers. It is the same 301 body but Micron configures it with its MRS series cartridges: an MRS-PC sediment and carbon block combo in stage 1, an MRS-RO50 membrane, then an MRS-34M mineralising post filter. That is a different media mix from the Lan Shan-branded 301, so match your cartridge codes rather than assuming a one-for-one swap.

If the number after the prefix on your cartridge matches (05, 34, RO50) and the cartridge is the short 7-inch body with the twist-in base, it is this family. Send us a photo if you are not sure.

Check before ordering: S2S, not S2, ST or S3S

Lan Shan makes the same filter media in several bodies, and only the S2S fits the 301. Look at the code printed on your current cartridge and its length:

• S2S- short 7-inch twist-in cartridge, about 235 mm long: this listing
• S2- 10-inch twist-in cartridge, about 296 mm long, used in the LSRO-801, 802, 302 and EQ5A: see our Lan Shan S2 replacement filters
• ST- 10-inch cartridge with a different fitting, used in the EQ hang-type purifiers: not interchangeable
• SB-, SBS-, S3- and S3S-: different bodies, not interchangeable with S2S

The three stages

Stage	Cartridge	What it does	Replace
1	S2S-05 Sediment	5 micron polypropylene; removes sand, silt, dirt and rust down to a nominal 5 micron	Every 6 months
2	S2S-34 Granular Carbon	Acid-washed granular activated carbon; reduces chlorine, taste and odour and protects the membrane. Lan Shan labels this cartridge "carbon post filter" but the 301 runs it before the membrane	Every 6 to 12 months
3	S2S-RO50 RO Membrane	TFC reverse osmosis membrane, nominal 50 US gallons (190 litres) per day; rated by the manufacturer to remove 99.9% of dissolved solids, chemicals, metals, bacteria and viruses	Every 2 to 3 years, or when TDS rises

Intervals are a guide for typical town water. Poor source water, a large household or a TDS reading that climbs above about 40 ppm will shorten them. The 301's micro-computer reminds you when each stage is due.

The S2S family also includes an S2S-CTO carbon block, S2S-33 carbon and S2S-PC sediment-plus-carbon combo, and the membrane is made in 75 GPD as well as 50 GPD. If your system was supplied with any of these, contact us before ordering and we will confirm the right cartridge.

Packs

• Pre-Filter Pack: S2S-05 + S2S-34. The six-monthly change.
• Complete 3-Stage Pack: S2S-05 + S2S-34 + S2S-RO50. The full rebuild.

Specifications

• Size: 7-inch S2S series, approx. 235 mm long x 62.5 mm diameter (cartridge only, excluding the twist-in head)
• Flow rate: 1.5 LPM per cartridge
• Operating temperature: 4 to 42°C
• Operating pressure: 15 to 80 psi (the 301B without a pump needs good mains pressure; the 301A has its own booster pump)
• Membrane: TFC, 50 GPD nominal
• Made in Taiwan by Lan Shan Enterprise Co., Ltd.

Changing a cartridge

1. Close the feed water valve and open the faucet to release pressure.
2. Slide the 301's push-pull case open to reach the cartridges.
3. Twist the old cartridge a quarter turn and pull it out of the head.
4. Remove the cap from the new cartridge, push it into the head and twist until it locks.
5. Open the feed water and flush: 2 to 3 minutes for the sediment and carbon stages. After fitting a new membrane, drain the first full tank to waste before drinking.
6. Reset the filter timer for that stage on the control panel (see your system manual).

No tools are needed.

Water filters are for drinking water applications only. Do not use where the water is microbiologically unsafe or of unknown quality without adequate disinfection before or after the system. This listing supplies replacement cartridges only; the reverse osmosis system is not included.

Unsure which cartridges you need? Contact us here and send a photo of your current cartridges showing the code; we will confirm the right replacement.