RO Help - Membrane not lasting

[spruce]

Hi all. Could someone recommend a decent sediment pre filter please? I use a Merlin RO, and it has been recommended to me that I also use a sediment pre filter before the RO. What is a good one? Thanks in advance.

Ask @doug atkinson from Daqua to price you up a single sediment housing with bracket in either 10" or 20". Ask him for a housing with a clear bowl together with John Guest fittings to suit your hose.

A clear housing so you can see whats happening.

 

[ShropsWindowCleaner]

Ask @doug atkinson from Daqua to price you up a single sediment housing with bracket in either 10" or 20". Ask him for a housing with a clear bowl together with John Guest fittings to suit your hose.

Super advice, will follow up on it. Thank you!

 

[Jango]

Thanks for the info. 
I have just found out last week they have been doing some work in our road with the water. So maybe this weekend I should flush the system for a few hours. No doubt that’s the problem in the fluctuations. 

Well today I’ve thoroughly flushed my membrane for an hour. My water pressure is now 76 psi. With no booster pump. My TDS Reading going through  the RO membrane  is now 5. Coming out via DI at 1 ppm. So I’m now happy with the results. 

 

[Pjj]

Well today I’ve thoroughly flushed my membrane for an hour. My water pressure is now 76 psi. With no booster pump. My TDS Reading going through  the RO membrane  is now 5. Coming out via DI at 1 ppm. So I’m now happy with the results. 

To be fair you should be getting 000 out of the resin with a low figure of 005 from the ro , what size resin vessel do you have ?. Unless the TDS meter isn’t accurate.

 

[Jango]

To be fair you should be getting 000 out of the resin with a low figure of 005 from the ro , what size resin vessel do you have ?. Unless the TDS meter isn’t accurate.

8 x 22 14 litre. The meter is inline TDS. 
changed the resin at the end of April. 

 

[Iron Giant]

Thanks for the info. 
I have just found out last week they have been doing some work in our road with the water. So maybe this weekend I should flush the system for a few hours. No doubt that’s the problem in the fluctuations. 

I would be checking the sediment filter as if they have replaced old cast iron pipes they will have disturbed a whole load of sediment and it will have come through your water supply, pic of one of mine during pipe replacement works 

 

[Jango]

I would be checking the sediment filter as if they have replaced old cast iron pipes they will have disturbed a whole load of sediment and it will have come through your water supply, pic of one of mine during pipe replacement works 

View attachment 21411

Thank you for that. I have replaced it already. In all fairness the old one hadn’t discoloured. But I changed it to be sure. 

 

[Iron Giant]

Thank you for that. I have replaced it already. In all fairness the old one hadn’t discoloured. But I changed it to be sure. 

No worries, I have found that since the work was done in our area last year I have had more issues with sediment since, no where near as bad changed my sediment filter and carbon filter yesterday after 10 weeks, I don't normally change them that soon although bought some cheaper ones than I normally use I don't know what the spec is on these though https://daqua.co.uk/combofilter.htm I bought the Spectrum carbon & Sediment Filter Combo 2nd ones down.

 

[spruce]

No worries, I have found that since the work was done in our area last year I have had more issues with sediment since, no where near as bad changed my sediment filter and carbon filter yesterday after 10 weeks, I don't normally change them that soon although bought some cheaper ones than I normally use I don't know what the spec is on these though https://daqua.co.uk/combofilter.htm I bought the Spectrum carbon & Sediment Filter Combo 2nd ones down.

10" = 15000 litres

20" = 30000 litres.

What concerns me in my experience is that it's a 1 micron filter where the sediment filter is 5 micron. I found the carbon block filter blocked up very quickly with the sediment in our water supply when I bought a different make of 1 micron.

For me changing prefilters is a pain as I do it on a table in the drive way. The Fiberdyne prefilter set listed next is less than twice the price and it's service life is more than twice as long.

 

[Iron Giant]

10" = 15000 litres

20" = 30000 litres.

What concerns me in my experience is that it's a 1 micron filter where the sediment filter is 5 micron. I found the carbon block filter blocked up very quickly with the sediment in our water supply when I bought a different make of 1 micron.

For me changing prefilters is a pain as I do it on a table in the drive way. The Fiberdyne prefilter set listed next is less than twice the price and it's service life is more than twice as long.

Thanks good sir, your figures mean I've totally maxed mine out then as processing over a 1000 litres a day 5 days a week, I was been a bit greedy with my last purchase but I had always bought the Fiberdyne ones 

 

[Jango]

No worries, I have found that since the work was done in our area last year I have had more issues with sediment since, no where near as bad changed my sediment filter and carbon filter yesterday after 10 weeks, I don't normally change them that soon although bought some cheaper ones than I normally use I don't know what the spec is on these though https://daqua.co.uk/combofilter.htm I bought the Spectrum carbon & Sediment Filter Combo 2nd ones down.

Ok thanks. I use a spectrum sediment filter and a fibredyne. Carbon. 
Everything has been changed recently, so will see how things go. 
The filters etc seem to have gone up in price quite a lot recently. 

 

[spruce]

Thanks good sir, your figures mean I've totally maxed mine out then as processing over a 1000 litres a day 5 days a week, I was been a bit greedy with my last purchase but I had always bought the Fiberdyne ones 

The problem is that we just don't know how long they will remove chlorine from our water supply because we don't know how much chlorine is in our water.

@doug atkinson did say recently that there was very little to none in the water they tested, so a cheap carbon filter will do just fine.

As I mentioned recently, the first r/o I purchased was a second hand one and only a year old. The local lad I purchased from changed the prefilters for me but hadn't changed them since new.

The membranes were damaged when I got the r/o and had to be replaced. I found that out the hard way. The replacement membranes lasted 6 years with me changing prefilters every 3 months using the same water supply as the lad I bought the r/o from.

I learnt 2 things from this;

1) I need to change prefilters more often than once a year. This is the reason I have become so fixated about changing them when their recommend service life is up.

2) Don't buy a second hand r/o as inevitably the person selling it will be asking more than its worth. You will have to replace all filters very shortly after receiving it. Better to buy it completely new from the right supplier.

 

[spruce]

Ok thanks. I use a spectrum sediment filter and a fibredyne. Carbon. 
Everything has been changed recently, so will see how things go. 
The filters etc seem to have gone up in price quite a lot recently. 

The good stuff comes from the USA. The dollar against the pound is one cause. Expect that as this Western (including Australia) conflict with China progresses we are going to have much more stuff increasing in price IMHO.

 

[Jango]

The good stuff comes from the USA. The dollar against the pound is one cause. Expect that as this Western (including Australia) conflict with China progresses we are going to have much more stuff increasing in price IMHO.

Yes I guess your right. Which brand of sediment filter do you use? 

 

[spruce]

Yes I guess your right. Which brand of sediment filter do you use? 

Spectrum is fine. I purchased a number from Gardiner's when they were selling them off. I still have one set left.

I will probably go with the combo set from daqua next (if he is still doing it) as I'm also in need of some resin when he next has it in stock.

I'm not recommending this but last time I changed prefilters I thought I would try to apply the double Di concept to prefilters. I replaced my first sediment filter with the old 'spent' Fiberdyne filter and put a new one in the second prefilter. 

I can't see it's done any harm as a Fiberdyne filter can be used as a combo sediment and carbon block.

At one time Fiberdyne filters were sold as 5 micron. As they were the same rating as sediment filters any particles smaller than 5 micron passed through both filters. Any particles bigger than 5 micron were trapped by the sediment filter. I'm about half way through this double Fiberdyne set up's service life but don't see the first filter going a red colour like I would expect to start to see by now.

I see grippatank advise the Fiberdyne filters are rated at 5 to 10 micron. My findings seem to indicate to me that the sediment in our water is between 5 and 10 micron which is just passing through both filters. I will probably go back to my usual sediment/Fiberdyne filter combo next prefilter change.

 

[Jango]

Spectrum is fine. I purchased a number from Gardiner's when they were selling them off. I still have one set left.

I will probably go with the combo set from daqua next (if he is still doing it) as I'm also in need of some resin when he next has it in stock.

I'm not recommending this but last time I changed prefilters I thought I would try to apply the double Di concept to prefilters. I replaced my first sediment filter with the old 'spent' Fiberdyne filter and put a new one in the second prefilter. 

I can't see it's done any harm as a Fiberdyne filter can be used as a combo sediment and carbon block.

At one time Fiberdyne filters were sold as 5 micron. As they were the same rating as sediment filters any particles smaller than 5 micron passed through both filters. Any particles bigger than 5 micron were trapped by the sediment filter. I'm about half way through this double Fiberdyne set up's service life but don't see the first filter going a red colour like I would expect to start to see by now.

I see grippatank advise the Fiberdyne filters are rated at 5 to 10 micron. My findings seem to indicate to me that the sediment in our water is between 5 and 10 micron which is just passing through both filters. I will probably go back to my usual sediment/Fiberdyne filter combo next prefilter change.

Interesting post. We are always looking for the best way to do things. I find the spectrum sediment filter/ fibredyne work well. I buy from Doug at Daqua too. 

 

[Paul Symonds]

So I've gone and got an Axeon HF5-4040 and the fibredyne carbon filter with a sediment filtering too, the last one was so brown. 

However I fitted it on the weekend but it still doesn't work great. The TDS of the water going in is around 300 and the water coming out of the RO is only going down to 31/32. So already get less than 90% efficiency. I still haven't checked the the mains water pressure yet, I know I need to, but I still don't understand how it's still so high. So frustrating. 

 

[spruce]

So I've gone and got an Axeon HF5-4040 and the fibredyne carbon filter with a sediment filtering too, the last one was so brown. 

However I fitted it on the weekend but it still doesn't work great. The TDS of the water going in is around 300 and the water coming out of the RO is only going down to 31/32. So already get less than 90% efficiency. I still haven't checked the the mains water pressure yet, I know I need to, but I still don't understand how it's still so high. So frustrating. 

The 3 most important factors with 4040's are;

1) water pressure,

2) water availability measured at the r/o inlet in liters per minute. This is especially important as there are some outside taps that are plumbed into the cold water system with a 'punch clamp'. Example.

https://www.ebay.co.uk/itm/OUTSIDE-GARDEN-TAP-PLUMBING-KIT-WALL-TUBE-SELF-CUTTING-STOP-VALVE-HOSE-UNION/193455221144?hash=item2d0ad46998:g:sgYAAOSw6xZetInU

The hole made is small and this restricts the water flow even although the static water pressure is good.

3) waste to pure ratio when producing water.

@doug atkinson advises that it can take flushing of around 6 hours to achieve a good rejection rate. I have noted this. In the past the manufacturers must have used a different preservative because I only flushed this current membrane for 5 minutes at the most and it produced a rejection rate of 98% from then on.

 

[doug atkinson]

So I've gone and got an Axeon HF5-4040 and the fibredyne carbon filter with a sediment filtering too, the last one was so brown. 

However I fitted it on the weekend but it still doesn't work great. The TDS of the water going in is around 300 and the water coming out of the RO is only going down to 31/32. So already get less than 90% efficiency. I still haven't checked the the mains water pressure yet, I know I need to, but I still don't understand how it's still so high. So frustrating. 

When building systems I’m finding it’s taking longer to flush out the chemicals from the membrane.  After 4 hours of continuous flush it can be still sat at 90%.

i can have it in flush all day and still not get the pass results until the following day.

When measuring ppm do after 10 mins of production as that is a true reflection.  
 

A good way to tell if the chemicals are going is as soon as you set the waste valve the waste water is no longer cloudy 

 

[ShropsWindowCleaner]

I recently purchased a second hand Merlin RO unit. I had to buy two new membranes and a new carbon block. My tap water is 270ppm. The new membranes started production at 130ppm at 40psi. I ran it for around 6 hours through my booster pump at 90psi (slightly above manufacturers recommendations)??‍. However, after 6 hours the production had reduced to 11ppm. That is a 96% reduction rate, which for a Merlin is good. The point being, as has been thoroughly covered in this thread, that water pressure and flushing is key with new membranes. As I said I use a booster pump at 90psi (it doesn’t have a pressure switch). If I run the RO at my tap water pressure of 40psi, my RO produces 40ppm water. Pressure is so important. Hope this helps. 

 

[Paul Symonds]

Ok great, thanks. If my water pressure is low and I don't use a booster and so have a relatively high output tds, does that inversely affect the membrane or just mean I'll be using more resin? Thanks