[duncan h]

My friends done WFP for years. His water was always a low TDS, 60 ish and just used DI vessels. He has now moved and his water is about 130. He said he using more resin and was looking at a Ro system.
Someone told him the Merlin system is a lot better, than the 40 40 systems.
I know very little about them. Do the 40 40 have the same amount of waist as pure. Hes on a water meter.
Are these the Merlin ones
https://www.easyh2o.co.uk/product/merlin-tankless-reverse-osmosis-rrp-525-00-78?gclid=EAIaIQobChMIrZbK2oya2wIVbZPtCh222AyYEAQYAiABEgKq4vD_BwE
Which is the cheapest to run for him

[Spruce]

My friends done WFP for years. His water was always a low TDS, 60 ish and just used DI vessels. He has now moved and his water is about 130. He said he using more resin and was looking at a Ro system.
Someone told him the Merlin system is a lot better, than the 40 40 systems.
I know very little about them. Do the 40 40 have the same amount of waist as pure. Hes on a water meter.
Are these the Merlin ones
https://www.easyh2o.co.uk/product/merlin-tankless-reverse-osmosis-rrp-525-00-78?gclid=EAIaIQobChMIrZbK2oya2wIVbZPtCh222AyYEAQYAiABEgKq4vD_BwE
Which is the cheapest to run for him

Was it the salesman who has a lot in stock to sell?

[mike1986]

With a TDS reading of 130 it would probably work out cheaper to use double DI vessels than RO on a water meter.

[duncan h]

My friends done WFP for years. His water was always a low TDS, 60 ish and just used DI vessels. He has now moved and his water is about 130. He said he using more resin and was looking at a Ro system.
Someone told him the Merlin system is a lot better, than the 40 40 systems.
I know very little about them. Do the 40 40 have the same amount of waist as pure. Hes on a water meter.
Are these the Merlin ones
https://www.easyh2o.co.uk/product/merlin-tankless-reverse-osmosis-rrp-525-00-78?gclid=EAIaIQobChMIrZbK2oya2wIVbZPtCh222AyYEAQYAiABEgKq4vD_BwE
Which is the cheapest to run for him

Was it the salesman who has a lot in stock to sell?

yes. It was Air Force in Leeds

[duncan h]

With a TDS reading of 130 it would probably work out cheaper to use double DI vessels than RO on a water meter.

He does. 2 small ones.
I use 2 x 25 ltr and cant tell much difference between using 1 and 2. TDS of 60/80

[Spruce]

Merlins were designed as under kitchen counter r/o units sold into the American market as the third tap on the kitchen sink.

It was perfect for the job - open the tap and the r/o started to filter water, switch the tap off and the r/o switched off.  The r/o didn't have to work that efficiently, so early Merlins were renowned for efficiency rates of 90% and high water usage. A local windy has had two and at our water pressure of around 50psi he had a waste to pure ratio of 5 to 1.

He has since put a tap onto his waste to throttle the waste to pure ratio back to about equal. But he still gets product water at 9 - 10ppm from water at 100ppm. Hence he uses much more resin that I do.

IMHO they are good for their designed purpose but not good enough for a window cleaner's  r/o. They work but come at a cost, especially when we deal with large volumes of water when compared to what is used in a kitchen.

Granville Gold, now AuRavelling79 has a unit he bought from Gardiners. He is happy with his, but he does have high water pressure in Bristol where he lives. I think that newer models (PRF) produce less waste than their early Merlin predessors did, but I wouldn't consider one for window cleaning tbh.

If you do a search you will see a review Malc did on his about 18 months ago.

I will always recommend a 4021 or a 4040. The 4021 is comparable with the PRF. My 4040 has a rejection rate of 98% so my 8ppm per 100ppm of tap water mean a good saving on resin over time. So IMHO, the small monetary saving my mate made on buying his Merlin has quickly been erroded by the extra cost of resin to polish the higher tds off.

Edit; It should be my 2ppm per 100ppm is better off by 8ppm when compared to his Merlin at 10ppm per 100ppm of tap water source. So I'm better off by 8ppm. Thanks Don Kee. 

. 

[Don Kee]

Merlins were designed as under kitchen counter r/o units sold into the American market as the third tap on the kitchen sink.

It was perfect for the job - open the tap and the r/o started to filter water, switch the tap off and the r/o switched off.  The r/o didn't have to work that efficiently, so early Merlins were renowned for efficiency rates of 90% and high water usage. A local windy has had two and at our water pressure of around 50psi he had a waste to pure ratio of 5 to 1.

He has since put a tap onto his waste to throttle the waste to pure ratio back to about equal. But he still gets product water at 9 - 10ppm from water at 100ppm. Hence he uses much more resin that I do.

IMHO they are good for their designed purpose but not good enough for a window cleaner's  r/o. They work but come at a cost, especially when we deal with large volumes of water when compared to what is used in a kitchen.

Granville Gold, now AuRavelling79 has a unit he bought from Gardiners. He is happy with his, but he does have high water pressure in Bristol where he lives. I think that newer models (PRF) produce less waste than their early Merlin predessors did, but I wouldn't consider one for window cleaning tbh.

If you do a search you will see a review Malc did on his about 18 months ago.

I will always recommend a 4021 or a 4040. The 4021 is comparable with the PRF. My 4040 has a rejection rate of 98% so my 8ppm per 100ppm of tap water mean a good saving on resin over time. So IMHO, the small monetary saving my mate made on buying his Merlin has quickly been erroded by the extra cost of resin to polish the higher tds off.

.

I agree with the whole post, but are sure that bit in red is correct Spruce? (Unless my maths is off, which it has known to be, that only equates to a 92% rejection rate which for me would mean new membrane time...)

[Slacky]

I gave up on my Merlin after throwing a lot of good money after it in the form of membranes and a new bulkhead. It was chucking out water at 60PPM with an input of 300, even with a booster pump.

Ive now gone back to a AXEON HF4-4021 with same booster pump. Output is 10PPM. Not bothering with resin.

[Spruce]

Merlins were designed as under kitchen counter r/o units sold into the American market as the third tap on the kitchen sink.

It was perfect for the job - open the tap and the r/o started to filter water, switch the tap off and the r/o switched off.  The r/o didn't have to work that efficiently, so early Merlins were renowned for efficiency rates of 90% and high water usage. A local windy has had two and at our water pressure of around 50psi he had a waste to pure ratio of 5 to 1.

He has since put a tap onto his waste to throttle the waste to pure ratio back to about equal. But he still gets product water at 9 - 10ppm from water at 100ppm. Hence he uses much more resin that I do.

IMHO they are good for their designed purpose but not good enough for a window cleaner's  r/o. They work but come at a cost, especially when we deal with large volumes of water when compared to what is used in a kitchen.

Granville Gold, now AuRavelling79 has a unit he bought from Gardiners. He is happy with his, but he does have high water pressure in Bristol where he lives. I think that newer models (PRF) produce less waste than their early Merlin predessors did, but I wouldn't consider one for window cleaning tbh.

If you do a search you will see a review Malc did on his about 18 months ago.

I will always recommend a 4021 or a 4040. The 4021 is comparable with the PRF. My 4040 has a rejection rate of 98% so my 8ppm per 100ppm of tap water mean a good saving on resin over time. So IMHO, the small monetary saving my mate made on buying his Merlin has quickly been erroded by the extra cost of resin to polish the higher tds off.

.

I agree with the whole post, but are sure that bit in red is correct Spruce? (Unless my maths is off, which it has known to be, that only equates to a 92% rejection rate which for me would mean new membrane time...)

Your right it doesn't sound right. Even I'm confused. Thanks. But I know what I was trying to say. 

So lets get it right.  It should be my 2ppm per 100ppm is better off by 8ppm when compared to his Merlin at 10ppm per 100ppm of tap water source. So I'm better off by 8ppm.