Waste/pure ratio

[TimB]

Hi all, I have an RO4021 system, believe its a low pressure membrane but not certain.

Last month or so I've noticed production of pure dropping off. I put water through membrane at 100psi. Both sediment and carbon filters are new, and membrane is 4 months old, and resin 2.

Pure is coming out at 1 or 2 after Di and 15 from membrane so quality is good. But the flow is sooo slow and definitely slower than a couple of months back.

I get 1 litre pure a minute and approx 2.6 waste a minute. Used to be a litre pure in 40 secs. What on earth can I do?

 

[Pjj]

Hi all, I have an RO4021 system, believe its a low pressure membrane but not certain.

Last month or so I've noticed production of pure dropping off. I put water through membrane at 100psi. Both sediment and carbon filters are new, and membrane is 4 months old, and resin 2.

Pure is coming out at 1 or 2 after Di and 15 from membrane so quality is good. But the flow is sooo slow and definitely slower than a couple of months back.

I get 1 litre pure a minute and approx 2.6 waste a minute. Used to be a litre pure in 40 secs. What on earth can I do?

It could be that the water is now colder making it thicker thus slowing down your production rate. Depending on your TDS your waste seams a bit high to product ?.

 

[TimB]

It could be that the water is now colder making it thicker thus slowing down your production rate. Depending on your TDS your waste seams a bit high to product ?.

That's my worry. The waste is much higher. Weather did cross my mind but its not really colder here in suffolk than it was in March when I started using it.

My main worry -other than it taking a third longer to fill my van- is damage to the membrane lifespan over time.

 

[TimB]

It could be that the water is now colder making it thicker thus slowing down your production rate. Depending on your TDS your waste seams a bit high to product ?.

Tds out of tap is mid 300s, and 15 out of membrane.

 

[Pjj]

Tds out of tap is mid 300s, and 15 out of membrane.

@spruce is your man to work out membrane efficiency, can you manually adjust your ratio pure/waste ? Or is it pre set ?

 

[Pjj]

Just looking at your pictures what’s in the blue housings ? And what size do vessel dI do have ? Also looks like you have booster pump is pressurising mains pressure not just going into the ro ?

 

[TimB]

@spruce is your man to work out membrane efficiency, can you manually adjust your ratio pure/waste ? Or is it pre set ?

I turn that red valve in picture by waste outlet, to force pressure back up into membrane. Thr guage shows 100psi in pipes just before membrane.

If i turn the valve more, then it should improve ratios a little yes, but the psi/ bar reading goes through the roof just twitching it.

 

[Pjj]

I turn that red valve in picture by waste outlet, to force pressure back up into membrane. Thr guage shows 100psi in pipes just before membrane.

If i turn the valve more, then it should improve ratios a little yes, but the psi/ bar reading goes through the roof just twitching it.

Ok the booster pump might be to powerful for your set up you need the right pump depending on membrane type high or low pressure maybe @spruce or @doug atkinson could advise better than me . I would try reducing the waste a bit and see how it goes .

 

[spruce]

I would wait until @doug atkinson sees this post. Where did you buy your r/o from? The reason for asking is that I thought Champ membrane housings were no longer available and haven't been for quite a long time. Do you know what membrane you have @TimB ?

Low pressure Axeon membranes (HF5) work within 50 to 100psi. Axeon high pressure membranes (HF4) work between 80 and 105psi.

What do the production figures look like if you switched the booster off?

Let's say your tap water was 350ppm and your pure before di was 15, then we can work out the rejection rate or how efficiently that membrane is working.

350 - 15 = 335

335 divided by 350 = 0.957

0.957 x 100 = 95.7% efficient using your current setup.

I believe the water in Ipswich isn't good.

Kettles beware - Ipswich has the UK’s hardest water

Ipswich has the hardest water in the country according to a new study - leading to higher costs repairing and replacing kitchen appliances.

www.ipswichstar.co.uk

Apparently, Ipswich has the highest level of calcium carbonate in its water in the country. Calcium is known to block the membrane pores. Maybe you might need to invest in a water softener (more drama) to remove those calcium deposits and replace them with sodium deposits. Sodium is much kinder to membranes than calcium is.

Sorry!

 

[TimB]

I would wait until @doug atkinson sees this post. Where did you buy your r/o from? The reason for asking is that I thought Champ membrane housings were no longer available and haven't been for quite a long time. Do you know what membrane you have @TimB ?

Low pressure Axeon membranes (HF5) work within 50 to 100psi. Axeon high pressure membranes (HF4) work between 80 and 105psi.

What do the production figures look like if you switched the booster off?

Let's say your tap water was 350ppm and your pure before di was 15, then we can work out the rejection rate or how efficiently that membrane is working.

350 - 15 = 335

335 divided by 350 = 0.957

0.957 x 100 = 95.7% efficient using your current setup.

I believe the water in Ipswich isn't good.

Kettles beware - Ipswich has the UK’s hardest water

Ipswich has the hardest water in the country according to a new study - leading to higher costs repairing and replacing kitchen appliances.

www.ipswichstar.co.uk

Apparently, Ipswich has the highest level of calcium carbonate in its water in the country. Calcium is known to block the membrane pores. Maybe you might need to invest in a water softener (more drama) to remove those calcium deposits and replace them with sodium deposits. Sodium is much kinder to membranes than calcium is.

Sorry!

I have an HF4 membrane from Daqua. The housing is old, but originally from Daqua as well. Bought second hand.

Other window cleaners in ipswich don't seem to have the problem. Their membranes last years without softeners, although yes, the water here is trash.

I don't know what the numbers would be with booster off, but tap pressure is only 40 or 50 so I needed a booster.

 

[scottish cleaning service]

Do you flush the membrane?

 

[TimB]

Do you flush the membrane?

Yes, before each use. Usually 5 mins, but sometimes 10 and sometimes only a couple of minutes.

 

[TimB]

Would calcium build up affect pure/waste ratio like it has, but not affect TDS?

I hadn't replaced the black carbon filter in about 4 months before I did so recently. Was told by a few that it wasn't necessary until TDS changed. Maybe a stupid learning mistake, but could that have damaged the membrane by not changing it every 2 months? My usage is somewhere up to 7000 litres a month total - waste and pure combined.

 

[spruce]

Would calcium build up affect pure/waste ratio like it has, but not affect TDS?

I hadn't replaced the black carbon filter in about 4 months before I did so recently. Was told by a few that it wasn't necessary until TDS changed. Maybe a stupid learning mistake, but could that have damaged the membrane by not changing it every 2 months? My usage is somewhere up to 7000 litres a month total - waste and pure combined.

If calcium deposits block the membrane pores, then it's going to reduce the amount of pure output. That in itself will change the pure to waste ratio. I think you should phone Doug this morning and talk to him.

 

[TimB]

If calcium deposits block the membrane pores, then it's going to reduce the amount of pure output. That in itself will change the pure to waste ratio. I think you should phone Doug this morning and talk to him.

Thanks Spruce. I'll call him tomorrow as I have enough produced to finish my week, and maybe he'll see this by then. I cann't understand why TDS is still good, but this calcium thing may explain that.

It's a learning process and if I've wrecked the membrane, so be it. It won't happen again. The thing I struggle with is the not knowing or understanding why something isnt working. Hate throwing money at stuff just in the hope it will work. Thanks for the advice.

 

[spruce]

Thanks Spruce. I'll call him tomorrow as I have enough produced to finish my week, and maybe he'll see this by then. I cann't understand why TDS is still good, but this calcium thing may explain that.

It's a learning process and if I've wrecked the membrane, so be it. It won't happen again. The thing I struggle with is the not knowing or understanding why something isnt working. Hate throwing money at stuff just in the hope it will work. Thanks for the advice.

I'm not saying what the problem is, as I don't know. If the problem is calcium related, then I don't know why other windies in your area aren't complaining.

 

[Part Timer]

I'm not saying what the problem is, as I don't know. If the problem is calcium related, then I don't know why other windies in your area aren't complaining.

Isn't a 4021 membrane more likely to get blocked up with such a high TDS and high calcium. Would think he'd be better with a 4040?

 

[doug atkinson]

What is the product code of the filters as it may be the micron rating. If you got it from me then they are okay.

 

[TimB]

What is the product code of the filters as it may be the micron rating. If you got it from me then they are okay.

Hi Doug. I'm not sure as I bought them second hand, but kev - who also lurks on here and is who I bought them from- bought everything from Daqua so I'd be surprised if they aren't.

 

[doug atkinson]

Reading your first post you stated the pre-filters were new so did you not replace them.

 

[TimB]

Hi Doug. I'm not sure as I bought them second hand, but kev - who also lurks on here and is who I bought them from- bought everything from Daqua so I'd be surprised if they aren't.

The last filters I put in, I threw the packaging away so don't know product code. I will be taking everything apart tomorrow and seeing if something is wrong with the waste valve area.

Water is entering at 100psi and coming out way too fast at the waste outlet, but not the pure one. If needs be I'll throw my hands up and look at a 4040. A friend runs one of those so I'll have company.