[pikeman]

Got a 300 gpd ro. Just lately tds seems to be creeping up fast out of tap 280 tds out of membranes 29 tds do you think membranes need changing. Thanks in advance

[slap bash]

Your tds out of the tap is 280and your tds after the ro is 29. I would say your ro is working perfectly . 10 % when rises any higher would be a problem. It's _ 10 % this so optimal.

[nathankaye]

Got a 300 gpd ro. Just lately tds seems to be creeping up fast out of tap 280 tds out of membranes 29 tds do you think membranes need changing. Thanks in advance

Im thinking same about mine. I have a 450 gpd ro. When first set it up my tap tds was about same as yours. Out tds was about 09 and then thru di. A short while back i changed location of my ro and for some reason my tds out from ro shot up to around 15 and so started to use a booster pump to bring back down to 10. Now with booster my tds is about 20 from ro. My pre filters are fine and so thinking i need to look at replacing membranes. A little peeved as just about a yr old and i thought they last longer than that

[Spruce]

280 in, 29 out. Membranes are past due for replacement imho.

I was once told by Peter Fogwill in my early wfp days that 94% efficiency is about as far as the membranes should go before they should be replaced.

Using resin to polish out those 29 remaining ppm will be costing you.

Nathan, my 450 GPD membranes lasted me 6 years before their efficiency started to deteriorate. I bought the r/o second hand and it was a year old when I bought it. The membranes in the r/o weren't good and I eventually replaced them 6 months later. The previous owner replaced the prefilters for the first time when I bought the r/o.

12 years ago wfp was in its infancy and we knew nothing about this new technology, so much of it was trial and error.

I religiously replaced the prefilters every 3 months. I believe that this is why those 2nd membranes lasted so well. The first owner didn't and I believe that the reason why those first membranes didn't last was because of not replacing those prefilters. The tap water was the same as we live in the same town.

I now recommend using fiberdyne carbon block prefilters and replacing them every 3 months.

I replaced my 450gpd r/o with a 4040 rather than wasting money replacing the membranes. The 4040 is now 4 years old and still performing as it did when new.

-   

[Spruce]

Your tds out of the tap is 280and your tds after the ro is 29. I would say your ro is working perfectly . 10 % when rises any higher would be a problem. It's _ 10 % this so optimal.

The first Merlins could only achieve a rejection rate of 90% when they were brand new. So by that comparision, those membranes have lots of life left in them. 

[nathankaye]

280 in, 29 out. Membranes are past due for replacement imho.

I was once told by Peter Fogwill in my early wfp days that 94% efficiency is about as far as the membranes should go before they should be replaced.

Using resin to polish out those 29 remaining ppm will be costing you.

Nathan, my 450 GPD membranes lasted me 6 years before their efficiency started to deteriorate. I bought the r/o second hand and it was a year old when I bought it. The membranes in the r/o weren't good and I eventually replaced them 6 months later. The previous owner replaced the prefilters for the first time when I bought the r/o.

12 years ago wfp was in its infancy and we knew nothing about this new technology, so much of it was trial and error.

I religiously replaced the prefilters every 3 months. I believe that this is why those 2nd membranes lasted so well. The first owner didn't and I believe that the reason why those first membranes didn't last was because of not replacing those prefilters. The tap water was the same as we live in the same town.

I now recommend using fiberdyne carbon block prefilters and replacing them every 3 months.

I replaced my 450gpd r/o with a 4040 rather than wasting money replacing the membranes. The 4040 is now 4 years old and still performing as it did when new.

-

Not that i keep wanting to bring my disapointment up with P/f but i got my kit from them just last yr. I also got a box of prefilters to last a yr and i have been changing every 3 mnths. Because i used to have 2 10" di vessels, my prefilters are a slight over kill.  My first 2 are sediment filters, then a carbon filter and last one is the fibredyne (i kno does job of others,)

For first 8mnths tho, my ro sat on my water tank in van, secured. The failure in ro shouldnt be down to this tho i wouldnt have thought. But not sure

[Arnold Palmer]

Time is an odd way to measure the life of an RO.

Mine last a year(ish) but they are on all the time, so they literally last a year. If I only run it for 4 hrs a day I'd expect 6 years maybe. That would be the same volume of water, just over a longer period of time.

How often are you guys flushing the membranes? How long for? I always find a good long flush will get the TDS down a bit.

Also: I change my sediment filters once a week but my water is terrible.

[nathankaye]

Initially my ro would be on for 12hr a night and was for 5days out the week. For 8mnths. Now that i have an ibc tank it is on  for 12/14hrs once per week. (I fill 500litre tank in van from ibc then top up ibc with ro, once a wk)
When i had ro working daily, i would flush it for 5mins before every use. Now that my unit stands for several days, i run flush for about 10/15 mins before use.
I used to be paranoid about the tds but now im more relaxed. Currently cleaning windows fine with tds of 16/17.
I know there fine as i have checked (i do rows of houses  at a time and its a 2 min job just to go and check)

[SeanK]

280 in, 29 out. Membranes are past due for replacement imho.

I was once told by Peter Fogwill in my early wfp days that 94% efficiency is about as far as the membranes should go before they should be replaced.

Using resin to polish out those 29 remaining ppm will be costing you.

Nathan, my 450 GPD membranes lasted me 6 years before their efficiency started to deteriorate. I bought the r/o second hand and it was a year old when I bought it. The membranes in the r/o weren't good and I eventually replaced them 6 months later. The previous owner replaced the prefilters for the first time when I bought the r/o.

12 years ago wfp was in its infancy and we knew nothing about this new technology, so much of it was trial and error.

I religiously replaced the prefilters every 3 months. I believe that this is why those 2nd membranes lasted so well. The first owner didn't and I believe that the reason why those first membranes didn't last was because of not replacing those prefilters. The tap water was the same as we live in the same town.

I now recommend using fiberdyne carbon block prefilters and replacing them every 3 months.

I replaced my 450gpd r/o with a 4040 rather than wasting money replacing the membranes. The 4040 is now 4 years old and still performing as it did when new.

-

That's what's known as spending a pound to save a penny, at the rate your changing your Fiberdyne filters you could replace
a 4040 membrane every two years and be no  worse off, with some of the cheaper membranes you would be well out of
pocket.
I use budget pre filters ( £10 per set ) changed 3 times per year and get 6 or more years from my 4040 membrane.

[Spruce]

280 in, 29 out. Membranes are past due for replacement imho.

I was once told by Peter Fogwill in my early wfp days that 94% efficiency is about as far as the membranes should go before they should be replaced.

Using resin to polish out those 29 remaining ppm will be costing you.

Nathan, my 450 GPD membranes lasted me 6 years before their efficiency started to deteriorate. I bought the r/o second hand and it was a year old when I bought it. The membranes in the r/o weren't good and I eventually replaced them 6 months later. The previous owner replaced the prefilters for the first time when I bought the r/o.

12 years ago wfp was in its infancy and we knew nothing about this new technology, so much of it was trial and error.

I religiously replaced the prefilters every 3 months. I believe that this is why those 2nd membranes lasted so well. The first owner didn't and I believe that the reason why those first membranes didn't last was because of not replacing those prefilters. The tap water was the same as we live in the same town.

I now recommend using fiberdyne carbon block prefilters and replacing them every 3 months.

I replaced my 450gpd r/o with a 4040 rather than wasting money replacing the membranes. The 4040 is now 4 years old and still performing as it did when new.

-

That's what's known as spending a pound to save a penny, at the rate your changing your Fiberdyne filters you could replace
a 4040 membrane every two years and be no  worse off, with some of the cheaper membranes you would be well out of
pocket.
I use budget pre filters ( £10 per set ) changed 3 times per year and get 6 or more years from my 4040 membrane.

I know you look at things from a different angle with regard to filter changes, SeanK. 

Doug from Daqua mentioned that chlorine content in the water differs depending on how far away you are from the purification plant.

The reason why I focused on Nathan replacing his prefilters regularly was because his membranes are only a year old and already shot. He doesn't use that much water, so chlorine damaging his membranes prematurely has to be a  consideration in his case.

For me I happily ordered several GAC prefilters for my new (4 years ago) 4040.  As I opened the GAC filter I noticed a label with a warning that the service life of that c/b filter was 2500 gallons.

With a membrane costing £245 and a cheap prefilter, I worked out that if I took the manufacturers service life to heart, that prefilter would only be good for 5000 liters of pure. We use about 13500 liters of pure a month on average.

I also take your point to heart you made a while ago that the manufacturers have no idea how much chlorine is in the water, so its in their interests to give the worst possible figures. It could well be that those GAC filters will have a service life of 5000 gallons on our water supply.

-

[pikeman]

Thanks for the replies. Looks like I need new membranes. Been using the fiber dyne prefilled instead of the 3 prefilters. Was informed no need to flush the fiber dyne unlike the 3 prefilters which I used to flush before connecting to membranes. 

[Spruce]

Thanks for the replies. Looks like I need new membranes. Been using the fiber dyne prefilled instead of the 3 prefilters. Was informed no need to flush the fiber dyne unlike the 3 prefilters which I used to flush before connecting to membranes.

I'm sure there is a note in the filter that advises to run water through it for a while to get rid of any fines. I run water through it for  5 minutes or so.  I always disconnect the feed into the membrane so any grit doesn't contaminate it.

[pikeman]

Thanks spruce always helpful