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Is the DI in RO/DI important?


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#1
jamesb2012

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I have read many threads on this site and I have just been using distilled water to top off or the ocasionally purified tap and I keep hearing that I should use RO/DI but what does de-ionization do for your tank?

I learned in biology that de-ionizing water basically removes small trace minerals but, is it significantly enough to be much more different than simply just reverse-osmosis water? Personal experience would be best to hear.

#2
phiber_optikx

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The resin traps the remaining tds left behind. Ro removes around 90%. If your tap has around 400-500 tds then you would still have 40-50 tds readout before the d.I. resin. Important yes vital? No

#3
Deckoz2302

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Of course the DI is important. Say it R-O-D-I out loud.....then say R-O out loud....two letters just aren't as cool as four

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#4
C.I._Reefer

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I'm a bit more anal about my water, probably because my tap water has detectable copper and nitrate levels, But i personally wouldn't go without DI. Before DI(after membrane) my water is 18 TDS, and after it is 0. If my TDS gets over 0-1 tds, i change my resin. There is a 99% chance you have no clue what all is in your tap water, and water is the single most critical thing in a reef tank, so why risk it? Also, tap water "filters" dont remove TDS at all, only TSS, which makes them pretty much worthless for our application.

#5
AZDesertRat

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There are things RO alone is not particularly good at including phosphates, silicates and all forms of ammonia including nitrites and nitrates. It takes the combination of the two, actually it takes the a good sediment filter to protect the carbon prefilter which in turn protects the membrane which in turn protects the DI resin. Its a complete system fromstart to finish and takes every piece to work correctly and to last any length of time. Something as simple as a membrane only working at 96% efficiency compared to 98% efficiency cuts your DI resin lifespan in IN HALF. Or a poor quality sediment filter that does not protect the carbon block so it exhausts and allows chlorine through to toast your expensive RO membrane. Or a plugged or fouled sediment or carbon filter which reduces the presure to the RO membrane, again cutting its efficiency signoficantly again eating DI resin and wasting excess water down the drain.
Every piece is critical.
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#6
bizzarro

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I'm probalby the only one out of hte norm here in that I don't even use RO/DI water anymore.

Once I siphoned out the substrate to a bare bottom there's no need to use the RO/DI. I just filter through the 3 filters with sediment and carbon. It comes out to 150 TDS, tap is 300~.

I was dealing with a bad case of HA and now all that's eradicated to where I stopped using my SRO-LX1000-S skimmer and rely on the fuge and LR for the primary filtration. The tank is only 29G.

Edited by bizzarro, 29 March 2012 - 03:56 PM.


#7
godfathernikki

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There are things RO alone is not particularly good at including phosphates, silicates and all forms of ammonia including nitrites and nitrates. It takes the combination of the two, actually it takes the a good sediment filter to protect the carbon prefilter which in turn protects the membrane which in turn protects the DI resin. Its a complete system fromstart to finish and takes every piece to work correctly and to last any length of time. Something as simple as a membrane only working at 96% efficiency compared to 98% efficiency cuts your DI resin lifespan in IN HALF. Or a poor quality sediment filter that does not protect the carbon block so it exhausts and allows chlorine through to toast your expensive RO membrane. Or a plugged or fouled sediment or carbon filter which reduces the presure to the RO membrane, again cutting its efficiency signoficantly again eating DI resin and wasting excess water down the drain.
Every piece is critical.


Listen to this guy, he really knows his stuff. He's been helping me out with my ro/di system and now im getting 0 tds with the new setup.

#8
AZDesertRat

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Tell us what filters you have that remove half the TDS, I'm very skeptical. Sediment and carbon filters are in the 1 to 10 or higher micron range in most cases so remove only TSS or suspnded solids not TDS or dissolved solids which are in the 0.0001 micron range. You might want to check tha tagain and get back to us with some photos. It takes a RO membrane and deionizing resin to remove TDS so I am crying foul here.
You may get a couple TDS reduction which is the 1 or 2 ppm chlorine residual and a couple more which could be attributed to metals, VOCs and other things the carbon removes also but not half. Sorry, I'm not buying it.
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#9
fast93accord

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My tap water is 113ppm. Out of my RO its 6ppm. Out of the DI tap on my RO system its 0ppm. So it does make a differnce... Especially when you dont know what that 6ppm consists of...

#10
nor_cal_nano

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Once I siphoned out the substrate to a bare bottom there's no need to use the RO/DI.


huh? :blink:

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#11
LebaneseDlight

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along these lines, is a 4 stage RODI sufficient or do you need a 5+ stage (I have a 4 stage from BRS)?

#12
C.I._Reefer

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It is best not to think of it in stages really. In many cases it seems a simple 3 stage RO + di (sediment filter -> carbon block -> membrane -> DI resin) is just as good or better than more "stages".

#13
LebaneseDlight

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It is best not to think of it in stages really. In many cases it seems a simple 3 stage RO + di (sediment filter -> carbon block -> membrane -> DI resin) is just as good or better than more "stages".


Well, I know a RODI isn't something to skimp on, but their (BRS) 4 and 5 stage RODIs were rates pretty comprably by peer review, so I thought the 4 stage would be sufficient. I need to get a TDS meter.

#14
AZDesertRat

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Forget the word stages exists. Look at what the stages contain, not haw many there are.
The Spectrapure forund here for $120
http://www.spectrapu...RODI-REFURB.htm
will outperform most any system on the market that costs twice what it does. Its all about the components. Look for the finest micron ranges you can find and an absolute rated sediment filter is better than a nominal rated one. Also look for reef specific DI resins over off the shelf premixed resins for longest life, best performance and lowest cost of ownership.

Add a $25 handheld TDS meter and you have an awesome reef quality system.
http://www.spectrapu...preciation.html
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