[cybersye]

Hi there,
I'm really hoping someone can shed some light on whats going wrong
I've just replaced an ro man 450 gpd for a merlin, problem with  the ro man was the product tds was high (040 ppm) and 35 ltrs an hour. My tap tds is 350 - 380 ppm, and the pressure is'nt a problem, about 75 psi.
 So I've taken delivery of a replacement today, the merlin, I've run it 2 hours or more, tds out now 090! does it require time to settle down? the 450 took a little time but no way did it read as high as this! I've used a merlin before but not at my property, but only about a mile down the road. I'm completely baffled and fear I'm becoming completely obsessed with the ro's performance, I just wanted to set up a small holding tank and produce about 250 ltrs a day, never thought it would bring me this much grief, its taken the best part of 2 weeks to sort out when I need to be out working and still no conclusive answer
Anyone else in Brighton? what system do you use and your tds before di?
I'm beginning to think I've got a really bad water supply to my flat, some of you may have noticed my previous threads and questions relating to ro performance and tds, and I dont think anyone on here has got such bad results from their set ups as I seem to be having. I'm beginning to despair, seems like money down the drain
Simon

[AuRavelling79]

Have you double-checked your tds meter? 

Are the rubber rings/washers on each chamber tight and intact?

Is your product to waste ratio correct?

[Extremeclean]

Both of those sets of figures re TDS out are very poor. I am not surprised that the Merlin out is around twice that of the RO-Man one though.

Are you absolutely sure about your water pressure being 75PSI? If it is you should be getting very good performance out of both of these Ro's. Certainly far better than what you are getting. One other thought springs to mind.  Have you checked how accurate your TDS meter is?  Another thought is that some TDS meters can be set to read in multiples of 10 rather than 1. I would check the setting on your TDS meter first. Then work back from there. If you were to read your figures as 1's rather than 10's then thats the kind of performance you should expect given your pressure and TDS in.

[freshwater]

Sye,

As extreme says check your meter, or go buy another one to check it against. If that’s OK the check your pressure. At 75psi you should be getting good results on the ROman & slightly poor results on the Merlin. Allow a good few hours for all the disinfectant to wash out of the RO. BUT at 90% rejection which is average for a Merlin on water at 380ppm you should be getting about 38ppm so its not to far off, if you are lucky and get 95% rejection that still leaves 19ppm.

steve@freshwatersystems.co.uk

[cybersye]

tds meter is only couple of moths old, its the one cleantech do, with 3 digits so not set in multiples of 10, the ro man unit had an inline meter which fluctuated up and down by about 010ppm constantly, not only that it seemed to read about 020 ppm lower than the handheld meter but when I dipped that in water after di it read 000, so I'm pressuming the meter is not at fault here. Does the chemical in the membranes when new add much to the tds? the merlins handbook says to run for an hour to flush it through, I've been monitoring it about 2 1/2 to 3 hours and it still reads 090, how longs it take? I feel a bit daft now because I must've tried the patience of the supplier of 2 ro man units ( first was faulty) and now gone to another supplier for a merlin and things have just got worse!
Simon

[cybersye]

I'm absolutely sure of the pressure being 75 psi btw and followed the merlins handbook perfectly, silicone lubricant on the seals, everything tight etc.

[JM123]

if you have been overly zealous with the silicone the tds levels can be high for a day or so, try closing off the product outlet and run the merlin like that for half an hour.

[cybersye]

thanks jm123, I will try that now.
I think I'll leave it running tonight, hopefully( fingers crossed) I may get a beter reading by the morning.
cheers
Simon

[chris@c.m.s]

Simon my tds in Sompting is 275 after ro-man 100gpd 6-7ppm, I think it must be your tds meter if you need to check it against mine I can meet you half way one eve.   

[cybersye]

cheers Chris, thanks for the offer, I could probably borrow one tomorrow off someone else i know in saltdean. The merlin is portable enough that I may plug it into someone elses tap for a comparison. I'm beginning to wonder if the mains to my street is really bad quality. I've always had to filter my tap water to drink, it comes out really cloudy for a few minutes until it settles. I've heard people say on here that tds can be made up of so many different quantities ie; someone could have a higher tds and lower presuure and still get a better product out, depending on the chemical make up of the water.
Guess I'll have to wait and see tomorrow!
thanks
Simon

[Paul Coleman]

tds meter is only couple of moths old, its the one cleantech do, with 3 digits so not set in multiples of 10, the ro man unit had an inline meter which fluctuated up and down by about 010ppm constantly, not only that it seemed to read about 020 ppm lower than the handheld meter but when I dipped that in water after di it read 000, so I'm pressuming the meter is not at fault here. Does the chemical in the membranes when new add much to the tds? the merlins handbook says to run for an hour to flush it through, I've been monitoring it about 2 1/2 to 3 hours and it still reads 090, how longs it take? I feel a bit daft now because I must've tried the patience of the supplier of 2 ro man units ( first was faulty) and now gone to another supplier for a merlin and things have just got worse!
Simon

The number of digits on the TDS meter is not a guide.  Both types have three digits.  I know this because I bought a x10 TDS meter in error once.

[cybersye]

Success!
I explored all options, even drove the 7 miles to my mums and tested it on her supply, very little difference.
Went to a plumbers merchants and payed a few pennies for new slightly tighter o rings on the membranes and almost straight away  am getting 030 ppm product, hopefully it may drop further.
Leaves me very sceptical as to quality of us imported products I must say :
but atleast its sorted. I may try adding an additional pre sediment filter at some point as my tds is very high.
Thanks very much guys for all the help, phew I can sleep at night
Simon