[SPE]

filling up over weekend checked my tds and had creeped up a bit.
so have changed the pre filters and ordered new resin.
Have heard it said before that the rubber seals inside the ro itself can sometimes not seat in correctly and let water pass, going to check this too and want to know what the sealant is I need to buy that you coat the rubber o rings with ?? (if any) thanks, Simon

[mikecam]

filling up over weekend checked my tds and had creeped up a bit.
so have changed the pre filters and ordered new resin.
Have heard it said before that the rubber seals inside the ro itself can sometimes not seat in correctly and let water pass, going to check this too and want to know what the sealant is I need to buy that you coat the rubber o rings with ?? (if any) thanks, Simon

The pre filters are not going to improve your TDS. But its still a good idea to change them regularly. I'm not sure why you're trying to seal your RO membrane and changing the resin. Are you measuring your TDS after the resin?

[SPE]

filling up over weekend checked my tds and had creeped up a bit.
so have changed the pre filters and ordered new resin.
Have heard it said before that the rubber seals inside the ro itself can sometimes not seat in correctly and let water pass, going to check this too and want to know what the sealant is I need to buy that you coat the rubber o rings with ?? (if any) thanks, Simon

The pre filters are not going to improve your TDS. But its still a good idea to change them regularly. I'm not sure why you're trying to seal your RO membrane and changing the resin. Are you measuring your TDS after the resin?

I'm fully aware of that but thanks anyhow.
Maybe mentioning my tds rising confused the question a little, changed the filters as part of regular maintenance.
It was a quick question about a lubricant for the rubber o rings in the 4040 and did'nt want to get into a too long winded post as I was just out the door to work.
I went into a plumb shop and bought some silicone grease in the end.
but since you've asked Mike ( I do appreciate the help on here)

Hf5 4040
tap 248 ppm
tap pressure 50 psi
after ro 45 ppm
after di 10 ppm (have new resin on order)

reason I've bought the silicone grease is I am going to look at the condition of the seals in the membrane housing.
a product of 45 ppm seems very high for a 4040 ro and an hf5 one at that which is supposed to deal with lower pressures well. and yes I flush the membrane regularly.
People with a similar tap tds and 4040 to mine reputedly get lower readings after the ro in single figures. This is why I think something is not quite right.

If all seems ok then I guess I have two further options, membrane is on the way out (doubtful of this only about 3 years old and flushed each time and pre filters changed regular) or I need a booster pump to imrove its efficiency.

Thanks,
Simon

[luther1]

If your membrane is 3 years old then that is your problem unless you only purify a bucket full a week. Fine tune your waste to get a better reading. You will go through alot of  resin with that reading,even if you doubled up your di's. How many litres a week do you produce? Mikes right about the seals,they're made to last a lifetime so won't be a problem there.

[luther1]

Btw,you should be getting a tds reading of 6ish out of your ro with a tap ppm of 248. So i would say its definately your membrane,as i'm sure would Mike

[SPE]

ok thanks, I use 1200 - 1500 ltrs a week on average, but I dont think I ever got anywhere like 6 from it even when new more like 18 - 20

[luther1]

At 50/50 your membrane is producing 3000ish litres a week for 3 years then you've certainly had your moneys worth out of it. Try adjusting your waste to get it down though,'cos even new it was too high

[SPE]

Thanks Luther for your input.
I understand what you are saying about the waste tap, but I usually run it fully open and it still produces pure and quite quickly too, sure at 50/50 it produces even more but is this normal, should any pure be produced when the waste (throttle as in gaps instructions ) is fully open ? both the pure and waste have 1/2" hoses attached to them,
thanks, Simon

p.s. I have also read somewhere this evening that the self tapping type taps that you can screw onto mains pipework do not give as much pressure as your true mains pressure, any truth in this as thats how I have mine plumbed in ?

[mikecam]

It does sound like your membrane is due for a change.
Couple of points....
50 PSI is low pressure, and even though a HF5 is designed for low pressure its designed for 70 PSI, so at 50 PSI you aint gonna get the best out of it.
Anyone running a 40/40 at 50% waste and 50% product ratio will shorten the membranes life.

[luther1]

1/2" hose is fine and sometimes even with the waste fully open you will get a dribble out of the pure. The self tapping taps do reduce pressure because of the reduced bore

[SPE]

1/2" hose is fine and sometimes even with the waste fully open you will get a dribble out of the pure. The self tapping taps do reduce pressure because of the reduced bore

ok thanks luther its more than just a dribble though
what if I was to put a tap on the pure outlet from the ro ? ie; when the waste is fully open I could shut off the pure meaning all water would flow as waste, would this improve the flushing ? will definately look into getting a proper tap plumbed in and hopefully that will improve the pressure, looks like I'll just have to bite the bullet and buy a new membrane, shall get onto gaps  thanks to you too mike for the advice, Simon