[Pete Thompson]

"Backflush"?

I always thought 'backflush' was what you did to water softeners - ie backflush them with salt solution to restore them.

As far as I know, you only FLUSH an RO membrane, which means you fully open (or bypass) the restictor valve on the waster water outlet - thereby allowing all the water input to go to waste (except for a trickle that you always get from the pure outlet)

The idea of this is that any build-up of calcium or other crud is 'flushed' out.

Is that what you mean by 'backflush'?

You would be mad to get rid of a 4040 RO in my opinion they are the best by far if you want quick cheap water with very little hassle.

Agree 100% with this.  4040 is FAR better then the likes of merlin etc.

My 4040 unit produces approx 110 litres of pure (7 TDS) per hour without any booster pump. (tap pressure of 80psi)

[groundhog]

You would be mad to get rid of a 4040 RO in my opinion they are the best by far if you want quick cheap water with very
little hassle.
You have done something wrong somewhere, have you checked that the membrane is installed in the right direction ?
When you say back flushing do you mean running all the water to waste or flushing back through the waste outlet ?

Its not a 4040, the membrane is a 20", perhaps I should bite the bullet and upgrade to a 40? The membrane was installed about 5 months ago, and worked fine for sometime before it all started to go wrong, is there a guarantee on the membranes? My ROman 450 membrane was fine for 8 years or more! I backflush the way that Purefreedom told me, I wasn't aware that you could do it differently?

[Shane sharples]

"Backflush"?

I always thought 'backflush' was what you did to water softeners - ie backflush them with salt solution to restore them.

As far as I know, you only FLUSH an RO membrane, which means you fully open (or bypass) the restictor valve on the waster water outlet - thereby allowing all the water input to go to waste (except for a trickle that you always get from the pure outlet)

The idea of this is that any build-up of calcium or other crud is 'flushed' out.

Is that what you mean by 'backflush'?

How often are you supposed to flush? everyday before use or once a week? Less then that??

[groundhog]

Is there anything else I could try? or do you think that the membrane has had it? Its only 6 months old, but I cant think of anything else to try! Perhaps I should just bite the bullet and replace my 20" membrane with a 40"? More expense!! 

[Smurf]

Is there anything else I could try? or do you think that the membrane has had it? Its only 6 months old, but I cant think of anything else to try! Perhaps I should just bite the bullet and replace my 20" membrane with a 40"? More expense!! 

Is this the one you are using? http://www.purefreedom.co.uk/water-purification/950-gpd-high-volume-reverse-osmosis-system-20-membrane-20-hf4-with-large-booster-pump.html

[groundhog]

Is there anything else I could try? or do you think that the membrane has had it? Its only 6 months old, but I cant think of anything else to try! Perhaps I should just bite the bullet and replace my 20" membrane with a 40"? More expense!! 

Is this the one you are using? http://www.purefreedom.co.uk/water-purification/950-gpd-high-volume-reverse-osmosis-system-20-membrane-20-hf4-with-large-booster-pump.html

Yes that's the one, except that I replaced the HF4 with an HF5 membrane.

[Smurf]

Are you aware of tds creep? https://www.youtube.com/watch?v=gxNTz7Cf3As
When do you take the tds reading after the ro as tds creep can exhaust the resin quicker and give a false reading on how the membrane is operating?

[Smurf]

Also using a transfer hose to the van tank the pure can also creep too so needs bleeding off and checking until it drops back down to zero or whatever the tds is in your holding tanks. I tend to use a standard half inch garden hose for transfering water which is slower than using a large hose to the van. The reason for doing so  I can run it through another DI resin tank or two to make sure it's zero only going into it.