[windowwashers]

As I know very little about these I am asking for your advice.

Which in your opinion is the better merlin 720 GPD or a 40inch RO comprising of 2 x pre filters and one 40 inch RO membrane.

Which is cheaper to run etc and does what its meant to and thats to clean the water??
any pro's and cons.

Many thanks
Ian

MATT JEFF1 ?? you guys seem to know your stuff

[brightnclean]

The 40 inch.. hands down!!

The 40 inch is a proper RO designed for heavy use. It will give much better TDS reduction than a merlin. more output, and far..far less waste water. Some people will run a 40 inch system at only 20% waste but in a hard water area you are better at a 50/50 split.

The Merlin will chuck out at least 3 parts waste to one part permeate (processed water) but usually more like 5 parts waste to 1 part permeate. I am in a hard water area and the guys I know who have a Merlin get at best 90% TDS reduction so they eat resin. Especially those who use quite a bit of water every day.

The 40 inch will have 2 prefilters whereas the Merlin just has 1 x carbon filter before the membranes. I suppose if you are in a soft water area and dont care about waste then the Merlin would be O.K. but if you have a choice go for the 40 inch system.

Its a pretty simple equation in that the less TDS reduction you get from your RO the more resin you will use so whichever one is better at TDS reduction has to be better providing it gives you enough water for your needs and the 40 inch will give a much better performance on both counts.

OOPS    For got this:  Membrane replacement is pretty much the same cost. For the Merlin you need the set of 2 at about £85 each and a good, E.G an Osmonics Desal low energy 40 inch one will be around £185.00 but you will probably replace the 40 inch one at much greater intervals than the merlin ones.

[windowwashers]

The 40 inch.. hands down!!

The 40 inch is a proper RO designed for heavy use. It will give much better TDS reduction than a merlin. more output, and far..far less waste water. Some people will run a 40 inch system at only 20% waste but in a hard water area you are better at a 50/50 split.

The Merlin will chuck out at least 3 parts waste to one part permeate (processed water) but usually more like 5 parts waste to 1 part permeate. I am in a hard water area and the guys I know who have a Merlin get at best 90% TDS reduction so they eat resin. Especially those who use quite a bit of water every day.

The 40 inch will have 2 prefilters whereas the Merlin just has 1 x carbon filter before the membranes. I suppose if you are in a soft water area and dont care about waste then the Merlin would be O.K. but if you have a choice go for the 40 inch system.

Its a pretty simple equation in that the less TDS reduction you get from your RO the more resin you will use so whichever one is better at TDS reduction has to be better providing it gives you enough water for your needs and the 40 inch will give a much better performance on both counts.

OOPS    For got this:  Membrane replacement is pretty much the same cost. For the Merlin you need the set of 2 at about £85 each and a good, E.G an Osmonics Desal low energy 40 inch one will be around £185.00 but you will probably replace the 40 inch one at much greater intervals than the merlin ones.

Thank you for that m8 much appriecated

i am well green to this so any more replies would be welcome so I can get a few more opinions.

[Simply Clean Windows]

I run a merlin in a hard water area(424) tds going in and about 20/24 out,94% reduction, i got 2 new membranes at the start of the year from Pure Reflection ltd for £111 and a pre-filter for £20,£160 delivered inc vat,quite a bit cheaper than previously quoted,it pays to shop about.
Malcolm

[Pj]

Check your mains pressure too. 

If you're going for a 40x40 and you have low mains pressure you'll need a booster pump.  Another expense.

[brightnclean]

I run a merlin in a hard water area(424) tds going in and about 20/24 out,94% reduction, i got 2 new membranes at the start of the year from Pure Reflection ltd for £111 and a pre-filter for £20,£160 delivered inc vat,quite a bit cheaper than previously quoted,it pays to shop about.
Malcolm

You are doing exceptionally well to get that result from your merlin.Maybe you havent got a high calcium content in your TDS in.

The Merlin users around here are in the high 40/50's out of theirs.

Comparing a Merlin to a full blown 4040 system isnt comparing like for like though. They are like chalk and cheese.

I suppose if you are on a budget and want a decent amount of water without laying out much capital then perhaps a Merlin might fit the bill. Otherwise the 4040 wins hands down on all counts in the end. Performance, much less waste and less running costs when you take evrything into consideration and the ability to produce water much faster on decent water pressure. I used to run my 4040 at 45 PSI mains pressure and it still gave me plenty of water.

[windowwashers]

any more?? opinions

[windowwashers]

I run a merlin in a hard water area(424) tds going in and about 20/24 out,94% reduction, i got 2 new membranes at the start of the year from Pure Reflection ltd for £111 and a pre-filter for £20,£160 delivered inc vat,quite a bit cheaper than previously quoted,it pays to shop about.
Malcolm

You are doing exceptionally well to get that result from your merlin.Maybe you havent got a high calcium content in your TDS in.

The Merlin users around here are in the high 40/50's out of theirs.

Comparing a Merlin to a full blown 4040 system isnt comparing like for like though. They are like chalk and cheese.

I suppose if you are on a budget and want a decent amount of water without laying out much capital then perhaps a Merlin might fit the bill. Otherwise the 4040 wins hands down on all counts in the end. Performance, much less waste and less running costs when you take evrything into consideration and the ability to produce water much faster on decent water pressure. I used to run my 4040 at 45 PSI mains pressure and it still gave me plenty of water.

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