[Rogue Trader]

Whether i set the waste tap to 50/50 or 80/20 it seems that the same amount of filtered water comes out , which isnt quite enough , it is an old HF4 membrane , i probably get about the same as my merlin (albeit a better tds) anyone got any ideas?

[Lee GLS]

Whats you tap pressure?

[Rogue Trader]

Tap pressure is ok , about 11 o clock on the dial

[P @ F]

Personally , i drink more beer 

Rich

[mikecam]

Tap pressure is ok , about 11 o clock on the dial

Its a pretty useless answer that mate. Ok, or 11 o clock on the dial means nowt.
Anyway, if you've been producing water at a 50/50 ratio its pretty certain you have reduced the life of your membrane. The Reverse Osmosis process does not work that way. You should be looking to get 25% product water of what you put into the membrane. Yours sounds shot if its producing the same amount as a merlin.

[Sapphire Window Cleaning]

Tap pressure is ok , about 11 o clock on the dial

Its a pretty useless answer that mate. Ok, or 11 o clock on the dial means nowt.
Anyway, if you've been producing water at a 50/50 ratio its pretty certain you have reduced the life of your membrane. The Reverse Osmosis process does not work that way. You should be looking to get 25% product water of what you put into the membrane. Yours sounds shot if its producing the same amount as a merlin.

Mike do you mean on a 4040 you only get 25% pure and 75% waste?

[Dave Willis]

Maybe you've anwered your own question its an old membrane.

[Rogue Trader]

alright alright keep your hair on! - ill go and look .... 2.5 bar or 35 psi. maybe it is shot . and i havent been running it at 50 /50 for any real period i have just tried it like that for 10 mins or so.

[Lee GLS]

35 psi is quite low, you would be better of with the hf5, but a booster pump would definitely improve things

[Rogue Trader]

i think ill get a hf5 membrane .... i think around £200

[mikecam]

Tap pressure is ok , about 11 o clock on the dial

Its a pretty useless answer that mate. Ok, or 11 o clock on the dial means nowt.
Anyway, if you've been producing water at a 50/50 ratio its pretty certain you have reduced the life of your membrane. The Reverse Osmosis process does not work that way. You should be looking to get 25% product water of what you put into the membrane. Yours sounds shot if its producing the same amount as a merlin.

Mike do you mean on a 4040 you only get 25% pure and 75% waste?

Sort of. I mean thats what they are designed to produce and thats how it works. If you produce more than its designed for you would shorten the life of your membrane. It is a membrane and not just a filter, thats why it has 'waste'. That 'waste' is for a reason.

[Mike55]

slightly off subject and don't mean to hijack but can I just ask why a booster pump is required for your RO if you have a low psi?

Is it purely whether you want to produce the water 'quicker' or is it an actual requirement of the membrane?

Also could someone just give me a brief overview of how the membrane actually works and why there needs to be a higher waste to pure ratio.

I have recently purchased a 40/40 ro (second hand) and have no instructions so just gathering info I can from this forum.

Thanks, Mike

[mikecam]

slightly off subject and don't mean to hijack but can I just ask why a booster pump is required for your RO if you have a low psi?

Is it purely whether you want to produce the water 'quicker' or is it an actual requirement of the membrane?

Also could someone just give me a brief overview of how the membrane actually works and why there needs to be a higher waste to pure ratio.

I have recently purchased a 40/40 ro (second hand) and have no instructions so just gathering info I can from this forum.

If you have low PSI then you are not getting the full benefit of your RO membrane. The correct PSI for your membrane will give you its fastest production and it will also work correctly removing most of the dissolved solids in the water.
 There needs to be a high percentage of waste as it is this waste that takes away the impurities and not the membrane itself. Its not a filter in the truest sense of the word, if it was it wouldn't have 'waste', the 'filter' would just stop and hold the impurities.
 Here's a brief overview of RO technology......
http://www.eetcorp.com/heepm/RO_ReviewE.pdf

[Mike55]

Thanks Mike

[Sapphire Window Cleaning]

Tap pressure is ok , about 11 o clock on the dial

Its a pretty useless answer that mate. Ok, or 11 o clock on the dial means nowt.
Anyway, if you've been producing water at a 50/50 ratio its pretty certain you have reduced the life of your membrane. The Reverse Osmosis process does not work that way. You should be looking to get 25% product water of what you put into the membrane. Yours sounds shot if its producing the same amount as a merlin.

Mike do you mean on a 4040 you only get 25% pure and 75% waste?

Sort of. I mean thats what they are designed to produce and thats how it works. If you produce more than its designed for you would shorten the life of your membrane. It is a membrane and not just a filter, thats why it has 'waste'. That 'waste' is for a reason.

With this in mind I think I will stick with my 500GPD RoMan style RO unit, in the summer and with a booster pump I get 55-60% pure to 40-45% waste.
In the winter that drops to 40-50% pure and 50-60% waste.

[Frankybadboy]

Tap pressure is ok , about 11 o clock on the dial

Its a pretty useless answer that mate. Ok, or 11 o clock on the dial means nowt.
Anyway, if you've been producing water at a 50/50 ratio its pretty certain you have reduced the life of your membrane. The Reverse Osmosis process does not work that way. You should be looking to get 25% product water of what you put into the membrane. Yours sounds shot if its producing the same amount as a merlin.

Mike do you mean on a 4040 you only get 25% pure and 75% waste?

Sort of. I mean thats what they are designed to produce and thats how it works. If you produce more than its designed for you would shorten the life of your membrane. It is a membrane and not just a filter, thats why it has 'waste'. That 'waste' is for a reason.

With this in mind I think I will stick with my 500GPD RoMan style RO unit, in the summer and with a booster pump I get 55-60% pure to 40-45% waste.
In the winter that drops to 40-50% pure and 50-60% waste.

thought your where selling up matt :

[Paul Coleman]

i think ill get a hf5 membrane .... i think around £200

Sounds like an OK plan.  I have a HF5 at around 45 PSI and it gives me around 90 litres an hour of pure.  Will probably increase as weather warms up.  It is a new membrane though.