[cybersye]

A 400 ltr tank in van average tds of 350. Ro will be onboard van . I need advice on which ro would be cheapest to maintain, use the least resin and give me a quick fill time with the least waste water.Getting a parking space near my first floor flat is virtually impossible and sometimes I cant even park in same road. I'm soon to be renting driveway space with use of an outside tap but I dont want to be leaving the van there overnight so your suggestions/advice would be very helpful.
Thanks
Simon

[Paul Coleman]

A 400 ltr tank in van average tds of 350. Ro will be onboard van . I need advice on which ro would be cheapest to maintain, use the least resin and give me a quick fill time with the least waste water.Getting a parking space near my first floor flat is virtually impossible and sometimes I cant even park in same road. I'm soon to be renting driveway space with use of an outside tap but I dont want to be leaving the van there overnight so your suggestions/advice would be very helpful.
Thanks
Simon

Then you will be needing a fast RO.  Unfortunately, fast does not usually equate to cheap.  Presumably you will be wanting that 400 litres filled in maybe 3 hours - 4 top whack.  I understand that Merlins produce a lot of waste.  I have reduced my Merlin waste with a flow control valve which means higher TDS going into resin.  I had to reduce waste for logistical reasons.  Also, I question whether a Merlin would be fast enough.  My hunch is that you will need a 4040 to fill that quickly.  It is possible to have a twin 4040 system for even quicker filling.  Not cheap though but less waste than a Merlin and may well fill in the time window that you have.
Can't have it both ways on this one I think.  Slow and cheap or faster and more expensive.

[Andrew McCann]

It's got to be a decent 40 inch system for what you need Simon.

www.gapswater.co.uk is your best bet for a fast fill system with the new (ish) high flow ultra low pressure membrane.

I would call June there and tell her your position and you will get very good advice.

Andrew

[cybersye]

Thanks to you both
I think you,ve answered and echoed my thoughts.
I did'nt mention I already have a merlin. I find that it produces quickly but too much waste and still a high product (about 35 - 40 ppm in my case) so when I mentioned cheap to maintain I was more meaning economical (resin) more than purchase price. would anyone know how a 4040 would compare to a merlin, fill time and product tds ? I have looked on gaps site and considered a twin 4040, not cheap I know, but i imagine it would be cheaper to maintain? they soun a lot more straight forward to flush than a merlin so would i be right in thinking the membranes should last a lot longer?  how long would you expect a twin 4040 to fill 400lts with 350 tds and a pressure of approx 70 psi ?
Thanks
Simon

[alanwilson]

cyber - if I would you I would look @ a 4040 in van, turn the waste down and preboost the water with a booster pump - as Andrew says the HF5 membrane is a good choice or the Desal AK4040TF which is what we use.

With the desal membrane and a booster pump it will take about 2 hrs to fill or if you turn the waste down to about 15% it will take around an hour.  Only problem here is the extra workload on the membrane so poss need a softener.

[cybersye]

Thankyou,
just had a look on gaps again the HF5 certainly looks like the one to go for
I feel like I've spent so much money over the last couple of years trying my hardest to set up on a budget but learnt alot too. A false economy maybe but best to test  the water (ahem  : ) before taking the plunge.
Anybody else use one of these membranes? whats your verdict?
Thanks
Simon

[alanwilson]

simon

I've dealt with June @ gapswater in the past - she's very good and to be honest I would go for whatever she recommends.

[cybersye]

simon

I've dealt with June @ gapswater in the past - she's very good and to be honest I would go for whatever she recommends.

Thanks Alan I shall give her a call.