Choosing your membrane
The membrane is the heart of your reverse osmosis system.
Below we have a selection of membranes, make your selection based on your water conditions and flow rate requirements.
Each membrane kit will come with the chosen membrane, appropriate AXEON PVC housing and brackets for mounting.
You can upgrade to a twin system. A twin system not only increases your production it also halves your waste water. You can upgrade to a twin system later by purchasing another membrane kit and if using ½" John Guest fittings you can buy the twin retro fitting kit to connect it to your existing set up.
Axeon HF5-4040 (4" x 40")
This has become by far the most popular membrane since its introduction in 2009 and represents the pinnacle in low pressure membrane design. The HF5-4040 is your best choice if your pressure is low or if you are unsure of your pressure as it works best under most conditions. It produces water approximately 30% faster than other low pressure membranes and at low pressure will give you the best tds.
This membrane will still work when a pump is added but we've found it does not perform as well as the other membranes below in terms of water quality. This is because it is a high flow membrane and requires a high feed flow to work well. When you add a pump the pressure goes up but as pressure increases the flow rate drops so most pumps cannot provide it with enough flow to work at optimum performance.
AXEON HF4-4040 (4" x 40")
This membrane works well at higher pressures - over 50 psi although over 60 psi is ideal. It is also a good choice if you intend to add a pump. The disadvantage of this membrane is that it can struggle below 35 psi to produce water of good quality and flow rate.
GE AK90 (4" x 40")
This membrane replaces the old GE Osmonics AK4040 (also known as the DESAL AK4040). Like the HF4-4040 this is a good choice if you have good pressure or are intending to use a pump. It has slightly better rejection than the HF4-4040 so will deliver a better quality water. Like the HF4-4040 it struggles at very low pressures.
AXEON HF5-4021 (4" x 21")
This is a shorter version of the HF5-4040 so will have just over half the flow rate, however as it has a smaller surface area it can be used with a pump to good effect and we've found that it rejects better than its 40" version under tap water conditions delivers a lower tds so if speed of fill isn't your priority this is a good choice. The disadvantage is that for only a slightly lower cost you are getting nearly half the flow rate.
AXEON HF4-4021 (4" x 21")
Like the HF4-4040 this membrane is a good choice if you have good tap pressure or are using a pump. It isn't as fast as the HF5-4021 but it will reject better under good pressure conditions, at lower pressures the HF5-4021 will outperform it both in production and water quality.
AXEON HF5-4014 (4" x 14")
Like the HF5-4021 production will be lower but water quality will be better especially if used with a pump. The disadvantage is that this membrane will be much slower than a 40" or 21" membrane but if quality is more important this is a good choice.