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I’ve bought a pumped 200GPD RO which arrived yesterday afternoon. Just about set it all up but there’s not much in the instructions about flushing the membrane. When it’s a new system can anyone advise on how long to leave the flush open to clean the membrane before closing it off to make pure please? And how often to let it flush normally? I don’t make a lot of pure but I’m  fed up with more than an hour round trip to spotless water so got an RO instead.

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46 minutes ago, wgwindows said:

I’ve bought a pumped 200GPD RO which arrived yesterday afternoon. Just about set it all up but there’s not much in the instructions about flushing the membrane. When it’s a new system can anyone advise on how long to leave the flush open to clean the membrane before closing it off to make pure please? And how often to let it flush normally? I don’t make a lot of pure but I’m  fed up with more than an hour round trip to spotless water so got an RO instead.

I'm not all that knowledgeable on the subject of processing but until you get more informed advice, what I'd suggest is :

First backflush for a half hour. Maintenance backflush for about ten minutes every day or two.

 

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2 minutes ago, wgwindows said:

@Davy G thanks Davy. Forgive the newbie question but does backflush mean just to open the flush valve? Thank you.

No problem mate. Yes, exactly that. 🙂

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I'd suggest trial and error but with an initial flush of at least 4 hours. If not working properly then flush a bit longer. 

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doug atkinson

Don’t know what system you have but the flush tap if in line with the hose is open and this is flush mode. 90 degrees to hose it is closed and you will start producing pure water. Could you time how much it takes to produce 1 litre of pure.

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Sorry for the ignorance on this gents but I’ve noticed people talking about backflushing a lot lately. What is the difference between flushing and backflushing? When people say flushing I assume they are talking about opening the gate valve on the waste fully for a period of time while running the water. What then is backflushing?

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24 minutes ago, Rickadoo said:

Sorry for the ignorance on this gents but I’ve noticed people talking about backflushing a lot lately. What is the difference between flushing and backflushing? When people say flushing I assume they are talking about opening the gate valve on the waste fully for a period of time while running the water. What then is backflushing?

Both the same

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6 hours ago, doug atkinson said:

Don’t know what system you have but the flush tap if in line with the hose is open and this is flush mode. 90 degrees to hose it is closed and you will start producing pure water. Could you time how much it takes to produce 1 litre of pure.

@doug atkinson I flushed it for about 90 minutes. Then the resin cartridge in and made about 50 litres of pure and it was quicker than I thought it would be . I’ll time it tomorrow but knew I’d need a pump because of poor water pressure.

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13 minutes ago, wgwindows said:

@doug atkinson I flushed it for about 90 minutes. Then the resin cartridge in and made about 50 litres of pure and it was quicker than I thought it would be . I’ll time it tomorrow but knew I’d need a pump because of poor water pressure.

What you need to check is the tds of your tap water compared to the pure water's tds after r/o but before di. This will tell you how efficiently your membranes are working and if you need to continue to flush them or not.

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20 minutes ago, spruce said:

What you need to check is the tds of your tap water compared to the pure water's tds after r/o but before di. This will tell you how efficiently your membranes are working and if you need to continue to flush them or not.

@spruce my TDS was 255 from the tap this morning. Sometimes it goes up to about 270. While flushing the RO went down from about 40 at the start down to I think 13. I then put the resin cartridge in (it’s part of the unit I’ve got after the membrane) after turning the flush off and then it was reading 0. I’ve since filled about 50 litres and is at 0. Probably be trial and error as I’m new to making myvown water but happy so far (no leaks or anything 🤞). It’s a bit of a cheap set up due to funds so I’m filling a rainwater butt in the garage and all seems ok. I have a little submersible pump to get out the pure I need for the day. I think you can get quite a lot done without breaking the bank if you’ve got enough time to set it up. It’s not at the level of some systems I’ve seen though.

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12 hours ago, wgwindows said:

@spruce my TDS was 255 from the tap this morning. Sometimes it goes up to about 270. While flushing the RO went down from about 40 at the start down to I think 13. I then put the resin cartridge in (it’s part of the unit I’ve got after the membrane) after turning the flush off and then it was reading 0. I’ve since filled about 50 litres and is at 0. Probably be trial and error as I’m new to making myvown water but happy so far (no leaks or anything 🤞). It’s a bit of a cheap set up due to funds so I’m filling a rainwater butt in the garage and all seems ok. I have a little submersible pump to get out the pure I need for the day. I think you can get quite a lot done without breaking the bank if you’ve got enough time to set it up. It’s not at the level of some systems I’ve seen though.

You need to run the ro for around 5 to 10 minutes before taking a tds reading of the product water from the ro membrane. 255 in and 13 out means your membranes are only removing 95% of the dissolved solids in the water. Your aim is 97 to 98%. If you are relying on that inbuilt 10" resin housing you will be changing that resin very often.

The 450 gpd ro I had originally brought our original tap water down from 254 to 4ppm.

We have all got to be selective when buying on a budget. Eventually you will need to replace those membranes with ones that run more efficiently. Saving money on buying cheap membranes will be quickly negated by the increase resin costs to polish that water off.

Edited by spruce
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doug atkinson

I built a 450 GPD and put a booster pump on it and got a litre in 30 secs. Ppm was okay so very surprised from these new type of membranes. Will have to investigate further.

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43 minutes ago, doug atkinson said:

I built a 450 GPD and put a booster pump on it and got a litre in 30 secs. Ppm was okay so very surprised from these new type of membranes. Will have to investigate further.

The membranes I had in my 450GPD were Filmtec. I didn't have a booster pump but 1 liter in 30 secs is up in my 4040 territory with an HF5 membrane, 50psi water pressure and no booster..

What membranes did you use to get those results Doug?

Edited by spruce
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doug atkinson
2 minutes ago, spruce said:

The membranes I had in my 450GPD were Filmtec. I didn't have a booster pump but 1 liter in 30 secs is up in 4040 territory with an HF5 membrane, 50psi water pressure and no booster..

What membranes did you use to get those results Doug?

The new Spectrum membranes which are made from new membrane sheeting technology. Normal membranes you wouldn't get that but putting that amount of pressure would damage the membrane.

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39 minutes ago, doug atkinson said:

The new Spectrum membranes which are made from new membrane sheeting technology. Normal membranes you wouldn't get that but putting that amount of pressure would damage the membrane.

I thought you gave up on Spectrum because you weren't happy with their performance/had too many complaints.

What pressure are you talking about please?

Edited by spruce
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doug atkinson
2 hours ago, spruce said:

I thought you gave up on Spectrum because you weren't happy with their performance/had too many complaints.

What pressure are you talking about please?

They launched a new brand. From feedback from customers they are getting a better flow rate. Time will tell how long they last but performance seems to be good and they compete against the lower priced membranes. Pump was a 1.5gpm with open flow 150 psi. I only did it to check a flow restrictor on it to see what ratio I would get which was 50/50.

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9 minutes ago, doug atkinson said:

They launched a new brand. From feedback from customers they are getting a better flow rate. Time will tell how long they last but performance seems to be good and they compete against the lower priced membranes. Pump was a 1.5gpm with open flow 150 psi. I only did it to check a flow restrictor on it to see what ratio I would get which was 50/50.

Some of the blue water sailing yachts have on board water makers which are basically salt water desalinizes. They use much smaller diamt r/o membranes and housings and they have pumps driven by electric motors that deliver 600psi pressure.

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