Four stage filters
have four levels of filtration:

1. sediment
2. carbon
3. membrane 
4. ‘final filter’

Five stage filters
have five levels of filtration:

1. sediment
2. carbon 1
3. carbon 2
4. membrane 
5. ‘final filter’

Description

Gallon/Day

Reserve

Model No

Image

4 stage water filter

24 Membrane

3 gallon tank

HM-RO-4

5 stage water filter

50 Membrane

4 gallon tank

HM-RO-5M

5 stage, extra capacity water filter

75 Membrane

10 gallon tank

HM-RO-75

Water Filter

Description

Model No

Image

HM-RO-4

Semi-annual 2 filter pack (replaces sediment and carbon filters)

HM-RO-4-2PK

HM-RO-4

Annual 4 filter pack (replaces all 4 filters)

HM-RO-4-4PK

HM-RO-5

Semi-annual 3 filter pack (replaces sediment and both carbon filters)

HM-RO-5-3PK

HM-RO-5

Annual 5 filter pack (replaces all 5 filters)

HM-RO-5-5PK

HM-RO-75

Semi-annual 3 filter pack (replaces sediment and both carbon filters)

HM-RO-75-3PK

HM-RO-75

Annual 5 filter pack (replaces all 5 filters)

HM-RO-75-5PK