Twin 21" membranes are actually more efficient in use than a single 40" membrane.
Really?
According to Axeon who make the membranes, they say that their 21 inch membranes, the HF5-4021, have a permeate flow rate (pure water production) of 3780 litres per day
Therefore 2 of them would have a production rate of 3780 x 2 = 7,560 litres per day.
Their SINGLE HF5-4040 membrane has a production rate of 9,450 litres per day.
See for yourself here (on the specifications tab):
http://www.axeonwater.com/AXEON-HF5-Series-Ultra-Low-Energy-Membrane-Elements.html
How then can you claim that 2x21-inch membranes are more efficient than a single 4040 when according to their manufacturer they produce less water?
We prefer the quick-release head system on these compared to the Champ Housings heads.
I suppose that's all down to personal choice, but since you only need to open the housings to change the membranes once every 3-5 years or so, personally I don't think "quick release" is much of an issue here. I also have not found champ housings to be especially "slow release". You whip the snap ring off and pull, not exactly time consuming. Are you sure you really "prefer" them, and it's not just because that's all what Reach Higher Ground supply?
So far the only thing there is to justify that extra £292 is a bigger carbon filter. Since carbon filters are cheap as chips, sorry I just don't see the extra value.
I think the real reason that this EZ-pure is more expensive is because it isn't actually your product, it's "Reach Higher Ground"'s product. You have Reach Higher Ground as a middle man. I would bet the likes of Gaps water etc probably buy the components directly from the manufacturer and then assemble those kits themselves to sell. Here you have Reach Higher Ground buying the components, assembling the "kit" and wholesaling it to you at a profit. You then need to add your own profit on top.
Not having a go, just saying. I don't know why you don't simply order the components from the manufacturer and assemble the kits yourself.
Hi Pete
The figures you are quoting are laboratory figures based on ideal conditions with 25°C water at ideal pressures. We have found that the real world figures can be very different.
However efficiency is not always about production rates - we have found that twin 21" membranes are more efficient at producing water with less waste water and highest quality.
Quoting from Gapswater's own site about the 21" membrane kits -
http://www.gapswater.co.uk/acatalog/Reverse-osmosis-kits-for-window-cleaning2.htmlRO Kit with Fibredyne pre-filter - 4" x 21" membrane
If space is at a premium then a 4" x 21" membrane might be preferable. Flow is just over half the flow you would expect from a 4" x 40" membrane but rejection tends to be slightly higher, i.e. you should achieve an improved tds especially when used in conjunction with a fiberdyne CFB-plus pre-filter.In reality most of our clients do not need the production rate of a twin membrane system and a single 21" RO membrane will produce plenty of water for their needs. The single membrane versions are much cheaper. A twin RO is really only needed, we have found, for those doing a lot of commercial work and who are not able to leave the vehicle filling overnight. Looking at Jim's typical application above he can produce 110 lph from a single 21" membrane - overnight this gives his system the potential to make over 1300 litres.
The main reason we have chosen the EZ-Pure housings, with their unified carbon filter is because of its suitability for the packaging on our crash-tested systems. Because we stock them for these systems, we then also sell them as stand alone components or kits which we put together along with our own Filter Frames (RHG do not supply any of these parts as a kit to us).
Price-wise if you specify a 21" Champ housing, 21" RO membrane, a 20" Jumbo Pentek housing (nearest in size to ours), a 20" Jumbo Fibredyne carbon filter, John Guest fittings, waste valve, and John Guest Tubing, from any supplier (including Gaps) then the price will be much the same as our EZ-Pure single membrane kits, but they will not include a Filter-Frame. The EZ-Pure will also still have about twice the chlorine-reduction capacity of the 20" jumbo filters. In fact if you select the Gapswater 'RO Kit with Fibredyne pre-filter - 4" x 21" membrane' with the 20" jumbo filter you will spend an extra £69.10 compared to our EZ-Pure HF4 Kit1 and you will not have the benefit of the Filtre-Frame to mount it all on.
We are not attempting to please everyone with our RO and water filtration offerings - there is such a large choice on the market that clients can easily shop around if they want to.
It would seem that you are not actually aware about the UK supply market of RO and filter components. Gapswater are a very good and respected firm - however, just like most others, they buy membranes, housings and filters from UK based wholesale firms who import the RO and Filter components in bulk from the US. We also buy a lot of our components from the same wholesale importers that they do. The EZ-Pure unique products (housings, clamps & carbon filters) we buy directly from the US manufacturer and then import in bulk. By doing this we have cut-out the UK wholesaler as a middle-man.