5 year old membrane comes back to life

[Elite Aquaria]

I have an RO unit that I have not used in over 5 years. There still was some water in the carbon canister and the membrane was moist. I could not believe it. I fired it up a few minutes ago and to my amazement I was getting 8 microsiemens out of this 100 gallon per day unit. Reject water is about 200 uS. Tap is 150-170 uS. The membrane has some mildew on it. Looks like I got lucky.

Dan

[Ardan]

Just be careful, there might be bacteria growing on it and can be transmitted to the water.

hth
Ardan

[Elite Aquaria]

I was a little concerned about the bacteria also at first. I am just going to mix with some of my tap water and aerate for 24 hours. I am sure that the chlorine and chlorimine in my water will kill off any bacteria. Then I will treat the chlorimine with Prime.

Dan

[RandalB]

Got lucky dude...

RandalB

[Elite Aquaria]

RandalB,

Do you think this will be a problem?

Dan

[RandalB]

I personally wouldn't drink the water from it, but it may be OK for the fishies. Throw away all the other filters tho...

RandalB

[Elite Aquaria]

Any way to be certain? Would you use it or just by a new RO. Since A new RO is alot cheaper than a few Pair of Discus. Before I fired up the old one I was looking at the Typhoon III series from Walter. The price for the base unit is $199 and the extreme is $269.

Dan

[RandalB]

Nope, but the fact that the conductivity is so low is a good indicator.... Why get a new unit? Replace all the filters and you'd be good and safe to go. Rinse out the unit with a little bleach water and no filters, replace with new, good to go.

RandalB

[Elite Aquaria]

RandalB,

I currently will be using tap water but later will switch to well water once the well is completed. While I am using the tap water I will be running my water through a cubic foot of carbon then into my three stage RO unit. I was thinking of a 10 micron sediment filter for stage one then a 1 micron carbon filter for stage two.

When I switch to well water I was going to go through the cubic foot of carbon into 10 micron sediment stage 1, 5 micron sediment stage 2, 1 micron carbon filter for stage 3. I will be adding a stage.

What would you change?

Dan

[RandalB]

I'd say you wouldn't need the 1 Micron Carbon block after all that prefiltration. If you feel you want to keep a carbon block, 5 micron should be fine. I have found too much of a pressure drop through the 1 microns, and the membrane manufacturers (Dow specifically...) only require 5 micron.

RandalB

[Elite Aquaria]

RandalB

How about 10 micron sediment filter for stage one then a 5 micron carbon filter for stage two. Sounds like I will not ever need a third stage when I switch to the well water. The reason why I ask is I need to buy a new filter bracket and I have the option to buy one that holds 2, 3 or 4 canisters.

Dan

[RandalB]

Sounds good to me....

RandalB

[Elite Aquaria]

RandalB,

I just came across the RO & DI Articles you wrote in for the simply library. Fantastic write up and pictures. However, I have a few questions. Here are the two arrays for all members to see:

First Array
1.) 25 micron spun polypropylene sediment
2.) 5 micron spun polypropylene sediment
3.) 1 micron solid carbon block
4.) 100 gallon FilmtecTM membrane
5.) In-line OmnipureTM K2533 Polishing Filter

Second Array
1.) 5 micron Polypropylene Prefilter
2.) 1 Micron Carbon Block Prefilter
3.) 75 gallon FilmtecTM membrane
4.) Dowex C100E Mixed bed DI resin cartridge
5.) In-line OmnipureTM K2533 Polishing Filter

These units are equipped differently. I am sure this is due to the specifications of the two customers feed water. What I want to understand is why and when you use different prefilters. Additionally, what is the purpose of the In-line OmnipureTM K2533 Polishing Filter?

I am going to assume that Array one was for a well water feed and array two was for a tap water application. Please help to educate.

Dan

[RandalB]

Been a while on those, but I believe that one was in fact a well application with high sediment content and dissolved organics (Omnipure polishing filter..). I think the other was an RO/DI that was going to be used for drinking water (omnipure again) also.

I don't use the 1 microns anymore since I tested the pressure with and without it and found the higher pressure drop with the 1's.

RandalB

[Elite Aquaria]

What would be your filter Array for a Well water application and a Tap water application today?

Dan

[RandalB]

Depends on what's in the water...

RandalB

[Elite Aquaria]

I have no Idea what is in my well water yet so lets just do the tap.

Chlorine/Chlorimine
uS is about 140-160
Kh is about 3-4
PH around 7.6-7.8

Dan

[RandalB]

Sounds like Chicago Tap water...Without the additional info:

10,5 Carbon, 5 Carbon or 10, 5 Carbon, 5 GAC (cloramine removal).

Now since you are running "a foot of activated carbon" you can go with a 10 Micron Sediment and a 5 Micron Carbon or just the 10 Micron Sediement to keep carbon fines out of the membrane/unit.

RandalB

[Elite Aquaria]

Are the GE filters sold at Home Depot ok to use? They have a sediment and Carbon filter.

Dan

[Elite Aquaria]

10,5 Carbon, 5 Carbon or 10, 5 Carbon, 5 GAC (cloramine removal).
RandalB

I do not understand what you are saying here...What is the difference between the Carbon and the GAC???

Dan

[RandalB]

Carbon is a carbon block, GAC is Granulated Activated Carbon. Also, HD's filters are generally OK.

RandalB

[Elite Aquaria]

Do carbon blocks and GAC perform different functions?

Dan

[RandalB]

Nope, but there are treated types that are better for chloramine removal than blocks.

RandalB

[Elite Aquaria]

What are Blocks better for? I assume that my canister is GAC so it would be better for the chloramine removal.

Dan

[RandalB]

Carbon Blocks are best for chlorine and heavy metal. GAC is generally not recommended for RO prefiltration unless there is chloramine present and it's treated for chloramine removal.

RandalB

[Elite Aquaria]

Randalb,

Thanks for all the help...So I guess I will just go with a 10 micron sed, 5 micron sed, 5 micron carbon when I switch to my well water...I may add a GAC as a polishing filter.

Dan

[RandalB]

:thumbsup:

[Buckeye Field Supply]

I do not understand what you are saying here...What is the difference between the Carbon and the GAC???

Dan

Remember that activated carbon, be it in a block or granular form, whether common or catalytic, works in the presence of chloramine by splitting the chlorine and ammonia. With sufficient residence time, the carbon will adsorb the chlorine. It won't however treat the ammonia that has been split from the chlorine.