[Dazzler3370]

A few months ago I purchased a 25 ltr capacity Resin Vessel in a bid to having to change it less  often, however it doesn't seem to have worked.

TDS at tap is 295

I currently use 500ltrs per day 5 days a week.
I have a 40 40 Low pressure membrane with 3 Pre filter set up.
How can I keep my water a 000PPM longer.....
Should I increase how often I change my Pre Filters....

Do any of you guys know how long 25ltr bag of resin should last using my average of 500ltrs of pure per day, or is that a stupid question.

Cheers
Dazzler

[Don Kee]

Whats your outgoing TDS from the RO and whats the water pressure you’re running through the RO? (Boosted or unboosted)
How ofter are you changing your resin in your 25litre RO?
It’s a bit hard to answer your question without the above...

How long the resin lasts for isn’t really directly effected by your pre-filters, only if you’ve spent the prefilters so much they’ve  exhausted your membrane, but you’d still need to know your outgoing TDS to know.

[p1w1]

you also have not mentioned what your waste to pure ratio is set at.

[Spruce]

you also have not mentioned what your waste to pure ratio is set at.

Yep.......... and Dazzler also hasn't told us what membrane is in his r/o.

[andyM]

If you're not doing so already then you really need to regularly be taking TDS readings straight from the RO output BEFORE it hits the resin.
This will tell you far more of what is going on and if everything is running as it should be.
You also need to set the waste/pure ratio using a stop watch and measuring jug and taking TDS readings to find the best ratio for you.
I prefer to run at an approximate 50/50 ratio due to being on a water meter. 
I would highly recommend calibrating your TDS meter with calibration fluid on a regular basis to make sure it is accurate.
And  i always disconnect my RO output feed from my resin on start up until the TDS settles down (usually on takes 15-20 seconds) but it stops the resin taking the hit and expiring early. 

[Don Kee]

I have a 40 40 Low pressure membrane with 3 Pre filter set up.

you also have not mentioned what your waste to pure ratio is set at.

Yep.......... and Dazzler also hasn't told us what membrane is in his r/o.

[Spruce]

I have a 40 40 Low pressure membrane with 3 Pre filter set up.

you also have not mentioned what your waste to pure ratio is set at.

Yep.......... and Dazzler also hasn't told us what membrane is in his r/o.

  A couple of suppliers call their HF4 membranes Ultra Low pressure. The manufacturers specs say operating pressure  6.8 bar. That might be low pressure in hydraulic lift terms but not with household water tap pressures. That's ultra high pressure to us.

.

[Dazzler3370]

ANSWERS:
TDS from RO 37 so think thats my answer......!!!!
Water is Unboosted
Waste to Pure Ratio 50/50 approx, I  will use the measuring jug and stop watch to get more accurate

Membrane 40 40 Low Pressure

[SB Cleaning]

ANSWERS:
TDS from RO 37 so think thats my answer......!!!!
Water is Unboosted
Waste to Pure Ratio 50/50 approx, I  will use the measuring jug and stop watch to get more accurate

Membrane 40 40 Low Pressure

RO is shot...that's why your going through resin.

[gsw]

Very similar setup to you.
My TDS in is 370. I use the single pre filter gardiners sell. My psi in was about 40-45. I open the waste up to take the psi down by 5 so nowhere near 50-50 I’d have thought. (fills 1000 litre overnight ) I run the RO down the drain  until I see TDS out between 12 and 10 then switch it into the DI through to the tank.  25 litre resin lasts me about 4 months this way. I’ve got 11 litre vessel ( I think bought years ago) one bag gives me 3 fills. But I don’t pack it out.
I change resin around 5 ppm out.
If you change the membrane mine took about 2 weeks to “bed in” before my TDS out was low and consistent again.

Hope that helps. Greg

[Spruce]

ANSWERS:
TDS from RO 37 so think thats my answer......!!!!
Water is Unboosted
Waste to Pure Ratio 50/50 approx, I  will use the measuring jug and stop watch to get more accurate

Membrane 40 40 Low Pressure

3 prefilters. Is it a Collin's water r/o?

[Spruce]

I'm inclined to support the reason SB cleaning gave you. Your membrane is shot.

I'm going out on a limb here!

 There are only a couple of reasons why a membrane wouldn't last.

First is chlorine contamination or/and quality of the supplied membrane.

Lets go for chlorine contamination.

I'm going to use Spectrum prefilters as an example.  BTW you only need 2 prefilters for window cleaning, a sediment and carbon block filter. Suppliers who sell 3 sell r/o's that include the 3rd to improve water odour and taste. (If your water has very little sediment, then a Fiberdyne 5 micron carbon block filter will also suffice as a sediment filter as well.)

The carbon block is the most important as it removes chlorine. Chlorine eats away at the material membranes are made from.

GAPS water also sell Spectrum prefilters and they do have a copy of the spec sheet.
http://www.gapswater.co.uk/acatalog/10--Pre-Filter-Set--2-Filters--8200.html#SID=800

(look under the documents tab for the spec sheets)

If you look down you will see that the 10" c/b filter has a service life of 6000 liters and a 20" 12,000 liters. That service life includes both of the water to waste and the pure you produce. (There are other cheaper carbon block filters for sale with an even lower service life, ie 10000 liters.)

You use 500 liters a day and you have a 50/50 waste to pure ratio (ie 1 liter of waste to 1 liter of pure produced = 2 liters) then your daily water useage is 1000 liters plus flushing tme. (Our water flow at the tap is 13lpm so for a 5 minute flush I would add another 65 liters to the 1000 = 1065liter.) In a 5 day working week I would use 5325 liters of water. If I had 10" Spectrum filters then I would need to replace that carbon block filter on the first day of week 2 as that's when my service life of 6000 liters is up. If I have 20" prefilters then I need to change the c/b filter every 12 days.)


Lets take this further with the 10" filter example. In the last 3 months we have been able to work just about every day so at 1065 liters a day x 60 days we would have used 63900 liters of tap water. But that 10" filter is only good for 6000 liters. If you are using 20" then again 63900 liters is well over the service life of the filter.

Logic tells us that the manufacturers don't know how much chlorine is in our water at any one time. So they would work on the maximum amount of chlorine the water authority would use to dose the water in your supply. So you could only have half that amount of chlorine, you don't know. But if you did then your 10" filter would only then have a service life of 12000 liters.

So if I'm only changing my prefilters every 2 to 3 months then the service life of my c/b filter has long since expired.

 Ever since  have had my 4040 I have used Fiberdyne carbon block prefilters. The 10" is good for about 38,000 liters and the 20", 76,000 liters. Mine gets changed when the water usage, ie 76,000 liters has been used. It might be 2.5 months or 4 months, it depends on how much water we use.  Our 4040 HF5 Axeon membrane is 6 years old and still performing at 97% efficiency.

Membranes;

There are many cheap 4040 membranes available, but IMHO they are a waste of money long term. What you save initially you will spend many times over with buying resin. Sorry, but the chinese copies aren't up to the standard of American manufactured ones.
Companies such as Collins Water sell water purification products to other industries where an efficient membrane isn't the most important factor. They then find a new market to sell to - window cleaners. Their cheap chinese membranes soon show up poorly against USA manufactured products in everyday use.

They all work but as a membrane losses its efficiency we use more resin to polish the remaining dissolved solids from the pure the membrane didn't remove.  Unfortunately, window cleaners will still continue to buy from these suppliers because they are persuaded to do so due to the initial purchase price savings to be had.

BTW Gaps water also sell Fiberdyne carbon block prefilters as do Grippatank. I used to buy mine from Gardiners but they are discontinuing the sale of filters as they take up to much storage space for too little financial return.

 

I hope that helps.

 

[windowswashed]

Fibredyne filter has been the best filter I've found for prolonging the life of R/O's to date.  I wouldn't buy a Chinese R/O poor investment, always buy a decent R/O pays in the long run and always run off for a couple minutes before producing purified water to prolong the life of R/O. Keep the waste water ratio at 50/50 last longer

[Dry Clean]

Fibredyne filter has been the best filter I've found for prolonging the life of R/O's to date.  I wouldn't buy a Chinese R/O poor investment, always buy a decent R/O pays in the long run and always run off for a couple minutes before producing purified water to prolong the life of R/O. Keep the waste water ratio at 50/50 last longer

First point is don't fall for the Fibredyne nonsense, just buy a carbon filter that's the same weight at a fraction of the price and use it as you would a Fibredyne ,  the cheaper filters tend to have the same amount of carbon (which is what counts when it comes to lifespan) but tend to gave a lower lifespan on their spec sheet, will let you guys work out why. lol.
Second point, adjust the water/waste to the point where you are getting the lowest pure tds, what this is will be will depend on water pressure, membrane condition and so on, the only thing that you shouldn't do is close off the waste fully as this will damage the membrane.
Will agree on the third point which is don't buy cheap membranes and always buy from a reputable dealer.

[Michael Peterson]

Can only speak for myself and my water but I get about 190 going in to a 2 pre filter 4040( have had this set up for five years on second 40 40 has 450gpd before that)and 4 coming out , previous 40 40 was similar output stayed at 11 for about a year and then up to 30 when i started buying resin. The fibredene filters never worked for me , every time I’ve tried them they have lasted only half the time of the traditional cheep ones