more ro stuff

[Dragbag]

What make are you ro membranes m8?

 

[Den]

Tested my water pressure today 65 psi i have the 450gpd what is the optimum pressure to run the RO.

Thanks.

 

[Dragbag]

This is from the Collins

Tested my water pressure today 65 psi i have the 450gpd what is the optimum pressure to run the RO.Thanks.

water eBay shop...

The input water must meet the following criteria for proper Reverse Osmosis function:

• Temperature must be less than 45 degrees Celsius
  
• Iron content no more than 0.1 ppm
  
• Water pressure must me a mimimum of 40 psi (2.75 bar)To acheive maximum water production you would require the optimum 80 psi of water pressure
  
• PH not less than 3 and not more than 11
  
• TDS under 1000 ppm recommended
  

Can I ask what tap tds and ro tds is

 

[Den]

Ppm is approx 260 tap then 6 to 7 after RO thanks for the info.

 

[trevor peacock]

I've got the collins 450gpd ro unit, I've also got the aquatec 8800 booster pump which is the only decent pump you can leave on overnight.

My tds is 330, when I first got the ro unit it took it down to ten, it's now up to 20, I've just changed my prefilters for the first time after 11,500 of water as recommended.

I spoke to collins and they said my figures are about right, they said the prefilters wont affect the tds just make the ro membrane last longer.

They also said the membrane is best changed when the tds gets to about 30, but it's up to the individual depending on how often they want to change the di resin, ( I assume in the long run it's cheaper to change the membrane than to keep coughing up for resin? )

Collins use the HID chinese membranes, am I better off getting the american ones when I change and if so where's the best place to get them?

Collins said they'd let me have 3 x 150 membranes for £60.

 

[Dragbag]

hi trev tx for you participation on this subject, we have had a little chat about this ro system which has helped me! also im talking to spruce about it as well, for the purpose of getting things right from the get go.

came across this site Water Purification Products - Shipping Included - Best Water Softener - Whole House - Laboratory which gives you a rejection rate of 94% mine is the same system as yours but all new membranes im gettin 96.5% rejection. which according to ro man site is "classed" as good.... not great but...just good:thumbsdown: as for membranes ill go for something from daqua probably Axeon 150gpd RO membrane..

 

[Dragbag]

also trev can i ask do you have your flush valve closed! or slightly open ?? and if slightly open did that help with you tds?? i get 1l of pure at 14tds to 40mill of waste at 80psi ( thats flush valve shut) dont know if i open the flush valve slightly to to get 1 to 1 would that reduce the tds.... i know nothing about ros!! just learning :rof:

 

[Dave B]

I have my waste open about a quarter usually as it makes a big difference

 

[Dragbag]

to your tds? i get a liter a min, just like to get the tds down a bit.... the instructions dont tell you to do anything but flush it now and then nothing about ratios

 

[Dave B]

If i open my waste a quarter I get my tds to drop from 9-10ppm to 3-4ppm

Not much difference at all to how quick i produce it but half the tds

 

[Dragbag]

thats interesting... "why dont the instructions say that" ( rhetorical) any one have link on this subject to a ro fanboy site?

 

[doug atkinson]

Hi grade membranes like Dow and Axeon the best you will get is 98%. However some ro systems are configured to save waste water so you will get around 96/97%. Vontron has a rejection rate of 96%. Life of these membranes will be a lot less hence the cheep price and if you read the reviews of the product a lot of people are not even getting 96% rejection rate.

Collins Water are a good decent company and pricing will be reflected on what quality are looking for.

 

[Dragbag]

tx doug.. iv been tuning my ro in this morning and got a 97% rejection rate, dont think ill get better! tap tds of 390 ro tds 10 with a 1 l pure to 1 l waste in 1 min, flush valve open about a 3rd, at 70psi that will have to do...do you advise to rejecting the first 10 mins or so of pure before putting it through the di??

 

[doug atkinson]

When your r/o has been idle as soon as you start it the ppm will be high. Just flush for around 5 mins and the ppm will settle down.

 

[trevor peacock]

I'm also fairly new to this, I get 2 lts good to 1 lt of waste, so about the same as you draggers!

I assumed the flush was either open or closed, this open a quarter lark is news to me.

Can anyone explain?

 

[trevor peacock]

Also Spruce you said "The general consensus is that your membranes should remove between 97 and 98% plus of the dissolved solids in your water. Once that percentage drops to around 94% its time to replace your membranes."

My tds is up to 30 ( was ten when I started in March) According to you I should change my membrane at about 20 as my tap tds is 330.

I've followed Collins instructions and changed my prefilters at 11,500 lts and I'm running at 80psi.

Collins also said the tds does creep up over time, is this right?

What am I doing wrong Spruce???

 

[trevor peacock]

bloody confusing all this science stuff!!!!

 

[AGlassAct]

Your not doing anything wrong Trevor, Spruce is saying it's more efficient to replace at 30 - in your case - as you will be going through more resin the higher the TDS after RO - which is false economy as resin is so expensive. It's perfectly fine to continue with the membrane, like Doug says make sure you give the membrane a good flushing ( full waste open ) before and after production as the TDS spike on initial start up is high ( prob around the 300+ mark with your TDS). I always disconnect the DI until the TDS has stabilised then connect it again when I am happy to put it through it.

Sent from my iPhone using Window Cleaning Forums mobile app

 

[spruce]

I'm also fairly new to this, I get 2 lts good to 1 lt of waste, so about the same as you draggers!I assumed the flush was either open or closed, this open a quarter lark is news to me.

Can anyone explain?

If you use loose tea leaves to make your tea (not teabags) then you need a tea strainer to stop those tea leaves going into the cup. But as the caught tea leaves build up in the tea strainer they block the holes and restrict the flow of tea into the cup. The only way to get the flow going again is to flush the tea leaves from the strainer under the tap.

Your membrane is doing something similar with removing the minerals from your water, but the removed or separated minerals need to be flushed away.

In the early r/o days RoMan sold two different in line restrictors for the waste water pipe. The most common was a 3 : 1 waste to pure and the other was a 5 : 1 ratio for hard water. So my r/o used 4 liters of tap water to produce 1 liter of pure (3 : 1).

Whilst a better ratio if you are on a meter is 1 : 1 and even maybe 1.5 : 1, restricting the waste will lead to slightly 'premature' membrane failure. But your increased water cost will probably cost much more than replacing a set of membranes a little sooner.

IMHO a ratio of 1 waste to 2 pure is pushing it a bit far, especially on your water hardness, but again that's my opinion. A water meter can change one's perspective on a matter.

The 94% efficiency was the figure used by Peter Fogwill, so his experience was invaluable in those early days. But that doesn't mean that it is a figure cast in stone. If you bought a new Merlin in those days then the best you could get was 90% efficiency on a ratio of around 5 : 1. But as my mate round the corner found out, putting a waste tap on his Merlin and restricting the waste to pure to 1 : 1 increased the efficiency of his Merlin, reduced his resin costs and reduced his water consumption.

My experience is you have to find the sweet spot of your r/o. If you have too much waste your internal pressure drops and the r/o doesn't work efficiently. Restricting the waste too much has the same result.

Once your pure tds increases then your resin costs will also increase. There comes a time when replacing the membranes is more cost effective that using more resin.

-

 

[spruce]

Hi grade membranes like Dow and Axeon the best you will get is 98%. However some ro systems are configured to save waste water so you will get around 96/97%. Vontron has a rejection rate of 96%. Life of these membranes will be a lot less hence the cheep price and if you read the reviews of the product a lot of people are not even getting 96% rejection rate.
Collins Water are a good decent company and pricing will be reflected on what quality are looking for.

Hi Doug,

If their ULP2012 - 100 is the 100GPD membrane used in most RoMan type r/o's then their rejection rate is between 93% and 95%.

Either way, I would imagine that over the service life of an average membrane, the intial cheap price of the Voltron will cost more in resin than buying a Dow or Axeon at a slightly higher price.

I don't know Collins Water at all, but as I've posted before, they don't mention window cleaners on their website even although it appears that a fair few window cleaners buy from them.

Their website seems to be focus on residential and aquatic applications. The membranes they supply are well suitable for those applications.

But it seems that some window cleaners first consideration will be price related presuming all units on sale are the same. They clearly aren't.

 

[trevor peacock]

I didn't realise restricting the waste has an effect on the results!!

what exactly does " flushing" do, collins told me it just flushes out the stale water?