[herbiefatboy]

What the advantage of having two 4040 membrane running do you produce water quicker only I have see someone with 2 thanks

[Spruce]

What the advantage of having two 4040 membrane running do you produce water quicker only I have see someone with 2 thanks

You will produce water quicker provided you have enough water flow at the tap and water pressure. Pretty good chance you would need a booster pump and not draw more than 12lpm of water from the mains using a booster on a residential water supply.

If using a single 4040 membrane with a booster pump needs a supply of around maximum 9lpm then adding a second membrane becomes an issue. (Figures from Gardiner's website before they stopped selling booster pumps.)

[NWH]

Pointless unless you’ve got a booster pump apart from the fact the second RO would last longer than the 1st.

[Spruce]

Pointless unless you’ve got a booster pump apart from the fact the second RO would last longer than the 1st.

My choice would be to split the water supply into 2 before the input ports on the 4040 housings so each membrane is being fed with the same 'quality' of water.

I appreciate that the other way of connecting them up is to use the waste from the first membrane to supply the second. It apparently saves water so I'm guessing its again down to 'economies of scale' - water costs on a metered supply compared to reduced membrane longevity.

[NWH]

Is that not how a ionic 0 system works though Spruce I heard supplying the other RO with the waste from the 1st one killed the second RO pretty quickly ? 

[Spruce]

Is that not how a ionic 0 system works though Spruce I heard supplying the other RO with the waste from the 1st one killed the second RO pretty quickly ?

It does because the second is going to have to work harder.

Last time I took a reading from my waste it was 50% higher than my tap water. Our tap water is around 120 to 140 so its working from a low base. If memory serves me my r/o waste was around 175ppm.

The first r/o I had was a 225gpd unit that came from Peter Fogwill. He separated the supply from the prefilters into 3 and fed each membrane with the same tap water tds.

There were 3 ways those r/o's could be set up.
Peter Fogwill's way was the first.

2. The first membrane was feed with tap water, the second was fed from the waste of the first and the third was fed from the waste of the second.

3. The supply was divided into two and the first 2 membranes were fed with tap water. The wastes from the first and second membranes were joined together and fed the third membrane.

Ro-Man used to have a diagram of these methods on their website many many years ago. I don't know if they still have it.

I saw a couple of local cleaners r/o membranes were set up to number 3. I never saw another setup to the way mine was.

For me, it just made more sense to split the water from the prefilters and fed each membrane with that water.

[NWH]

A zero system would work well for you if that’s your water readings.

[Spruce]

A zero system would work well for you if that’s your water readings.

My current r/o is a plain, basic single 4040 with no fancy bells and whistles.  Our water pressure is 55psi atm and pure after r/o is 3ppm. The HF5 Axeon membrane is 7 years old and still performs at 97% efficiency. I have a 6 liter DI vessel . I change resin once a year on average.
I have a float switch so I can just leave the r/o to work and once the IBC tank is full it switches off without my input. I hardly ever flush it - I just change prefilters every 76,000 liters. I have a meter on the r/o to count down when those are due to be changed, usually every 3 to 4 months.

In the early days I upgraded that 275gpd r/o's membranes to 450gpd. It wasn't producing enough water for 3 of us back then so I assembled this 4040 using 20" prefilters.

My window cleaning days are numbered so I don't need anything fancy such as an Ionic Zero system. I had to justify replacing my 9 year old SLX pole at the end of last year.  It will probably be my last pole purchase in my window cleaning life, possibly it will still be around when I'm not - reality of life.

[NWH]

You retiring are you then.

[Spruce]

You retiring are you then.

I'm 4 years into my retirement. 

My moto is to retire when I expire. Unfortunately my expiry date is coming quickly.

As the saying goes; "Life is like a toilet roll. The closer it gets to the end the faster it goes." I can vouch for that.