[Granny]

Hi
Been using this Pentair PRF (Merlin) the water is about 280 out of the tap the product is 20 and that's it.
The flow rate is fine for me as I don't use a lot of water.
I think it's because of low pressure I don't know what the pressure is but there is no Woooooosh when you turn on the tap and the toilet is slow filling.
I've been using Double DI with water at 100 TDS for 10 years so I can live with 20 TDS.
My question is:
Will the low pressure and high output TDS shorten the life of the membrane or will it prolong the life of the membrane because it's not purifying to it's max potential?

[AuRavelling79]

Hi
Been using this Pentair PRF (Merlin) the water is about 280 out of the tap the product is 20 and that's it.
The flow rate is fine for me as I don't use a lot of water.
I think it's because of low pressure I don't know what the pressure is but there is no Woooooosh when you turn on the tap and the toilet is slow filling.
I've been using Double DI with water at 100 TDS for 10 years so I can live with 20 TDS.
My question is:
Will the low pressure and high output TDS shorten the life of the membrane or will it prolong the life of the membrane because it's not purifying to it's max potential?

In general terms the higher the pressure the better. I have a meter and a pressure gauge on mine. My pressure ranges from about 50 psi to 70 psi.
Most important is changing the carbon filter.

In Bristol TDS is usually about 300. During September my input was up at over 400. I think Bristol uses rain water from the Welsh hills and from Somerset and when it's dry weather the TDS goes up.

There was a time when I was getting 10 - 12 from my PRO but at the moment it is about 20/22.

Now we've had some rain I noticed the TDS has dropped from low 400's to mid 300's.

I will be running the RO over the weekend and I'll post some figures.

[Granny]

So 20 doesn't seem so bad then,  better than  what's coming out of the tap.
Don't understand this bit.
"Most important is changing the carbon filter."
I thought it was the Chlorine that killed the membranes.
Or is the carbon filter also a Chlorine filter?

[mac74]

So 20 doesn't seem so bad then,  better than  what's coming out of the tap.
Don't understand this bit.
"Most important is changing the carbon filter."
I thought it was the Chlorine that killed the membranes.
Or is the carbon filter also a Chlorine filter?

Yes the carbon filter is the chlorine filter.

[Don Kee]

So 20 doesn't seem so bad then,  better than  what's coming out of the tap.
Don't understand this bit.
"Most important is changing the carbon filter."
I thought it was the Chlorine that killed the membranes.
Or is the carbon filter also a Chlorine filter?

It’s made out of carbon, it filters chlorine.

[Spruce]

So 20 doesn't seem so bad then,  better than  what's coming out of the tap.
Don't understand this bit.
"Most important is changing the carbon filter."
I thought it was the Chlorine that killed the membranes.
Or is the carbon filter also a Chlorine filter?

...... and it needs replacing regularly.  Accordingly to the info I have its every 38,000 litres the r/o uses, which is waste plus pure.

[Granny]

Thanks a lot.
I don't really want the added complication of a booster pump and I'll keep an eye on the Carbon Filter but it's guess work estimating 38000 litres, now I know why one of the housings had red tape on it.
It's for the carbon filter so you know which one it is without having to open them all up!

[AuRavelling79]

Thanks a lot.
I don't really want the added complication of a booster pump and I'll keep an eye on the Carbon Filter but it's guess work estimating 38000 litres, now I know why one of the housings had red tape on it.
It's for the carbon filter so you know which one it is without having to open them all up!

I just wrote membrane, membrane and filter on each chamber in permanent marker.

I also bought a flow meter and a pair of half inch john guest fittings to take the guesswork out of it.

[mac74]

So 20 doesn't seem so bad then,  better than  what's coming out of the tap.
Don't understand this bit.
"Most important is changing the carbon filter."
I thought it was the Chlorine that killed the membranes.
Or is the carbon filter also a Chlorine filter?

...... and it needs replacing regularly.  Accordingly to the info I have its every 38,000 litres the r/o uses, which is waste plus pure.

So at that 38000L filter expire figure would i be right in thinking,
If it was taking me 3000L of water to make 1000L of pure in a IBC tank, (2000L waste meaning a 3:1 ratio) i would have to change the pre filters after say 12/13 full 1000L fill ups?
Cheers m

[Spruce]

So 20 doesn't seem so bad then,  better than  what's coming out of the tap.
Don't understand this bit.
"Most important is changing the carbon filter."
I thought it was the Chlorine that killed the membranes.
Or is the carbon filter also a Chlorine filter?

...... and it needs replacing regularly.  Accordingly to the info I have its every 38,000 litres the r/o uses, which is waste plus pure.

So at that 38000L filter expire figure would i be right in thinking,
If it was taking me 3000L of water to make 1000L of pure in a IBC tank, (2000L waste meaning a 3:1 ratio) i would have to change the pre filters after say 12/13 full 1000L fill ups?
Cheers m

Yes, but as Malc says, you need to instal a water meter before your r/o so you know when the service life of your prefilter is up. I never know how much water I draw from my IBC tank to top up my van. I usually just  fill the tank to the 3/4 mark these days. Sometimes I might put in 250 litres and other times 400 litres. There is no way I could estimate with any certainty when my prefilters were due a change just on my pure usage.

[AuRavelling79]

A half inch flow meter and a pair of John Guest fittings will set you back about £25.

[mac74]

A half inch flow meter and a pair of John Guest fittings will set you back about £25.

Good call, im going to do that.

[Granny]

A half inch flow meter and a pair of John Guest fittings will set you back about £25.

I must be thick but I can't find what I need to do the same, any idea of where I can get one?
Ta
Granny

[mac74]

A half inch flow meter and a pair of John Guest fittings will set you back about £25.

I must be thick but I can't find what I need to do the same, any idea of where I can get one?
Ta
Granny

Ive had a look on the net, but i think most read in cubic litres not litres? so 1 notch would mean 1000L maybe? Also not sure if can reset them ether?
Hopefully one of the above guys will give us a link?
Cheers m

[Granny]

A half inch flow meter and a pair of John Guest fittings will set you back about £25.

I must be thick but I can't find what I need to do the same, any idea of where I can get one?
Ta
Granny

Ive had a look on the net, but i think most read in cubic litres not litres? so 1 notch would mean 1000L maybe? Also not sure if can reset them ether?
Hopefully one of the above guys will give us a link?
Cheers m

Hi Mac
I've gone for this one mostly because of the choice of fittings.
https://www.ebay.co.uk/itm/353633665253
I'll let you know how I get on.
Granny

[mac74]

Yes, let us know, i wonder if you can reset them?
Cheers m

[windowswashed]

When it's noticeable that the RO is slowing down producing much less purified water in the same amount of time as normal then it's a good indication it's time to change the carbon filter, works for me.

[mac74]

When it's noticeable that the RO is slowing down producing much less purified water in the same amount of time as normal then it's a good indication it's time to change the carbon filter, works for me.

Tbh mate i reckon that may be to late?
I have a pressure gauge's on the in and out of my 2 x 20" pre filters, and i think that you would see a pressure drop on the out when they start getting clogged up, but NO? its the same new and when i change them, 80psi pumped. Spruce above says 38000L per change, and i think he knows his stuff, meaning 12/18 1000L fill ups give or take on your waste ratio. I think the water gauge is the way to go, hope granny above lets us know how he gets on with his 

[AuRavelling79]

A half inch flow meter and a pair of John Guest fittings will set you back about £25.

I must be thick but I can't find what I need to do the same, any idea of where I can get one?
Ta
Granny

Ive had a look on the net, but i think most read in cubic litres not litres? so 1 notch would mean 1000L maybe? Also not sure if can reset them ether?
Hopefully one of the above guys will give us a link?
Cheers m

Hi Mac
I've gone for this one mostly because of the choice of fittings.
https://www.ebay.co.uk/itm/353633665253
I'll let you know how I get on.
Granny

That's the one I have. The numbers to the right (in red) are litres. As in 1 (Black) plus 999 Red is 1,999 litres. The little red dial measures out one litre.

I believe you can go inside and reset them but I just stick a bit of masking tape on it saying change filter at XX,000 litres.