Tid Bit of truth about RODI filters

[Dave ESPI]

Reverse Osmossis DE-IONIZED WATER....

 

its Supposed to be De-ionized Reverse osmosis water.

 

I looked at ( and called a few manufactures....)2 of my units.

the 3 stage is simply RO.

the 5 stage is RODI.

The way they are designed to work, the DI is supposed to go before the tfc membrane. HERE IS THE DILLIO.......

DI water is... well missing an ion right>??

WELLLLLLLLL in Many metal (Iron, copper, brass, ) pipes, it pulls ions back out and will contribute to rusting them faster than normal oxidation. In Silicon plants, there are regulations that make the waste water have to re-add some ions. THERE IS INDEED TRUTH TO THE FACT THAT PURE DI water is a solvent. AFAIK, RODI is safe to store provided the container is food grade.

 

HERE IS THE MEAT OF THE POST.

The waste lines on rodi units spill 4:1 or 3:1 unused waters to the drain while only a little bit is actualy pushed in the lines as useable. This is why a pressure boost pump is recommended.

It can reduce waste to 2:1 in good units.

The DI part in 90 % of the units available is the last stage, in order to NOT waste DI resin life, or to add DI water with an empty vallance shell wanting an electron to fill the ionic imballance. If not supplied, it can corrode a 1/4 inch plate of iron to the thickness to paper in less than 32,000 gallons flow with DI water. WOW, that doesnt seem like ever possible, but it can be accomplished in less than 5 years. At a 4:1 ratio, its 32,000 waste to 8,000 gal RODI produced. I USE 8000 gal in one year. Of course The average reefer will never hit this mark, but then again.....

 

SOME RODI have a waste line that runs continuiously.

When purchasing one, make sure they have an auto shut off switch or that feature built in.

Also I have seen some units selling fer around 129-155.00 on Ebay as of recently. Be aware these are decent components of systems (many are made from parts from Applied Membraines)

BUT they dont include crap like, tightner wrenches, shut offs, connectors, extra RO line, bypass line adaptors or mounting brackets. You will spend around 60.00 MORE for the accessories that make having an RODI handy and a NEAT CLEAN presentation of a unit. if ya want parts and lines all over the place, by all means, just buy the pieces and sit it on the floor.

Be sure to run a plumbing line that is pvc to a natural drain area if the DI is NOT the last stage.

Puting the DI before the TFC or TFE membraine will make the membraine last longer, but at the cost of yer pipes.

Just food fer thought.

[ross76053]

Crap, Dave....where were ya a few days ago with I installed my new DI?

 

No biggie...I can easily change the lines. I've got a buddy in the business who gave me a hospital-grade DI unit fer nuthin'. Can't find a trace of anything in the water.

 

Thanks fer the info.

[Christopher Marks]

Putting a DI before RO is silly though. It would be exausted after about 50 gallons, and cost one heck of a lot to replace that often.

[Dave ESPI]

This is true in 3 stages Chris, not in 5 stages. From what I have been told, there is a pre RO canister that traps all the crap. Also, TFC and TFE membraines also are a variable in the quality of the unit. I would tend to agree with your logic though from a first impression.

[gobies]

Gah. I'm savin' up for a Kati/Ani system.

[Pikelet]

There is something very sexy about having a 3 stage RO/DI sitting on the kitchen counter next to the sink with coloured tubes running all over the place and a bucket on the floor.

 

Neatness is the sign of a poor lateral thinker.

[Dave ESPI]

I just couldnt leave well enough alone......

To add to Piks commentary.....

Do I make you Horny Baby ! Do I ? ? !! YEAHHHH!!!!

ahh yesss water sports......