RO UNITS: QUESTIONS AND ANSWERS

[DiscusJeff]

Yes we are on public water which uses chlorine. I take it that's my problem?

[RandalB]

Jeff,
If you haven't replaced your Carbon Block prefilter, you've probably killed your membrane.

The chlorine in your water attacks the material the membrane is made of pretty quickly. The carbon block prefilters absorb the chlorine and protect it. Unfortunately, they are only good for about 6 months under normal operating conditions (The Carbon Blocks that is..)

Sorry to be the bearer of bad news...
RandalB

[DiscusJeff]

I was afraid of that!

Do I have to buy the replacement from Kent or would any membrane be ok?

[RandalB]

Jeff,
Any TFC membrane would be fine, I personally recommend Dow Filmtec.

RandalB

[DiscusJeff]

What does TFC stand for anyways?

[RandalB]

Jeff,
Thin-film Composite Membrane

The other type is CTA or Cellulose Tri-Acetate

HTH,
RandalB

[czotalis]

Hi all.

The question i have is, how does someone store a R.O. when not using it. How long can it be out of use without the any of its parts getting damaged. Since i only have one aquarium i don't think that i will use the R.O. 24/7.

thanks chris

[Fish Freak]

Where can I get a RO unit?

Josh

[Miles]

I want to take this time to say THANK YOU to RandalB. Man he is the hook up for RO equipment and meters. Everytime I call Randal he tells me what I need and has it in the mail the same day.
THANK YOU RandalB

8) Miles

[RandalB]

Chris,
Sorry about the delay in answering your question, I thought I had notification running on this topic.

You need to run some water through your RO unit at least every 72 hours to prevent bacterial build up fouling your membrane. If you don't use it that much, keep the unit in the fridge for up to a week-10 days.

HTH,
RandalB

Josh, Got your IM...

Miles, Thanks Bro!

[Huy Nguyen]

Hi all

I have a R/O unit. It's all hooked correctly but not seem to have enough water pressure to push it to the final (TFC membrane) stage. I had the water company checked my water pressure. It is at 50 bls. at street and 50 bls. at my hose. Do you think this is the problem?
Do I need to buy R/O pump?

[nokoto]

Hi yet another question

How do you test if the membrane is damaged....

What component do you test for.


Wayne

[RandalB]

Wayne,
Check the TDS and volume of the output water.

If the TDS is higher than normal, change the prefilters. If it's still high, Check your water pressure. If it's above 30 PSI. you're membrane is probably damaged and was probably damaged by chlorine.

Decreased Water Volume
Decreased production at standard pressure and temp (after a prefilter change) usually means Scale or Bacterial fouling problem.

How to Check for a fouled (Scale or bacterially) Membrane:

1) Turn off your water and drain the RO unit.
2) Open the Membrane housing and remove the membrane carefully
3) Smell the membrane. If it smells rotten or foul it's bacterially damaged and should be replaced (Flush the housing with bleach and rinse completely)
4) If it doesn't smell foul, gently squeeze it. If it makes a crackling noise or has a crunchy feel, it's scale fouled and should be replaced.
5) If none of the above applies, check the "O" rings for damage.
6) If no damage, relubrucate the "O" rings with RO water or Silicone lube and reinstall.

This method will not detect membranes damaged by drying out or freezing the high TDS will be the only way to tell.

HTH,
RandalB

[stygian7]

I'm setting up my auto water changer. I have determined that my pH is the same out of the tap as it is after 48 hours. I plan to run the water directly into the sump for the wet/dry filter.

Here's my question: I want to mix my R.O. with tap water so that I don't have to reconstitute the water. If I use the waste R.O. water to mix with the pure R.O. water am I just mixing R.O. with dechlorinated tap water of highly concentrated tds? I don't know whether the membrane traps the solids or if it just rejects them and concentrates the waste water. Last thing I want to double check is the average production:waste ratio. If I'm thinking correctly, most R.O. unit produce about 1 part pure/7 parts waste.
Thanks in advance,
Kevin

[RandalB]

Kevin,
RO Waste is not generally extremely high TDS water. It should be about 20% higher than your tap water.

RO Units generally operate in the 4-5:1 Waste: Product range unless your pressure is low or your water is cold.

The Membrane should not trap anything, the waste should carry it away..

RandalB