[Steve Weatherley]

I use a merlin for my RO system. Today I measured the waste water compared to the pure water production and got the following result. For every 1 litre of water which passed through the merlin only 17.5% was pure water the rest being waste.
This was kind of expected - a result of approx 1 part pure water to 6 parts waste
My water pressure in is about 50psi.

I am thinking of changing my system as I am on a water meter so this is a 2 part question...........
1. What is your production ratio?
2. What system do you have?

[Steve Weatherley]

C'mon guys surely this is something anyone should consider if they are using a water meter..................

Or do you not know the answers?
 

[Wizard]

I would try to increase the pressure on the membrain with a pump it has improved my output to 50/50>i do not use a merlin but the merlin chaps will I am sure inform you.

[paul rulton]

sorry 2 jump in guys but will that pump idea work on all systems? :

[Steve Weatherley]

I hear that these pumps can also burn out easily too???

[paul rulton]

will ask my dad 2moro whether it can b done with a central heating pump would do the job he was a plumber for 50years so he should know
do u guys want me 2put his answer up 2moro or u not bothered

[Steve Weatherley]

yes please any detals would be useful. Thanks

[Steve Weatherley]

still nobody seems to know their own ratio of pure / waste??

[Wizard]

Let me put it this way. I use my tap water straight to my r o 300 gal per day.My psi was 40 my waste was 70% and pure 30%. I fitted a cheap pump that pumped at 50psi and my quality improved about40/ 60 waste my pump can work from 9 volt to 14.2 volt at 14,3 it has a psi of 80 and the quality went to 50% WASTE AND 50%PURE.sO THE PUMP DID THE JOB. What I needed was a high gals pre minute pump. mine pump at 2,9 litres per min and I feel I should have a pump that delivers 5 litre per minute. I must say my pump cost 25 pounds and leaked like hell so I glued all the parts together with epoxy no more leaks. T I am killing this pump but it is stilling going for its life some days at 27/7. Its the transformer that burns out. This transformer is variable and cost me much than the pump. Williams pumps sell a Merlin booster pump try there web site. I have learned by trial a error. I also found it difficult to get help on the forum as far as R O go. The thing I now is low psi your ro water has a height tds and you Di has to work harder and that cost money, increase you psi and tds comes down by 10 -20 % . Hope this makes sense

[Steve Weatherley]

appreciate your time and info wiz

[StanA]

C'mon guys surely this is something anyone should consider if they are using a water meter..................

Or do you not know the answers?
 

You could fit a tap on the waste pipe to reduce the waste but it would mean higher TDS after the RO so more resin used.
I use a Merlin with a restrictor - though that's more because it's sited at someone else's place and they wanted the waste flow into the ditch reduced.  It's not a metered supply.

[actualcleaning]

Steve....i use a merlin system and have done now for 2 years +.
My tds in is 450+ (hard area)...out 25 - 50 (depending on temp).
My psi from outside tap is 40 so i bought a booster from gardiners two years ago from a couple of hundred quid and the prssure into the merlin is now 75 psi.
My production rate at this pressure is approx 40% (+/- 2/3%)...and i do measure it fairly often.
In the two plus years that i have been using the merlin i have never changed the membranes and have never backflushed or changed the pre-filters.I use 25 ltrs of resin every 4-6 months to polish it off and i make approx 250 ltrs a day of water.
I looked at a 4040 system but why change what isn't broken.
 

[Filllllll]

yep.Same here.Pressure from tap 65.Ratio of 1litre pure to 3 waste.Seems higher the pressure.better the waste ratio.
Also I dont mess about with the back flushing on my merlin and also only recently changed membraines after 3 years.Pre filter every six months (apparantly should be every 2 weeks on my usage)Resin change every six months also.
I wouldn't of thought merlin was best option if on meter though.I use it coz I dont need static tank.