DO I reallly need....

#1
An RO/DI unit? Im starting a 20 gallon ish(maybe larger) reef tank, and I know RO is practically needed, but what about the De-Ionization? I would like to know cuz I mould rather spend my money wisely, rather than buying extra $hi! i dont need. If u know anything, please explain./
 

Joe Fish

Superstar Fish
Apr 21, 2006
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#4
Well, any nitrite is bad and too much nitrates are also bad. Test for phosphates if you can. I used tap for a while and fought a up hill battle with phosphates and nitrates. You never know what else could be in your water that will only come out down the road. When to ro/di and they were gone. The DI part will help remove just about anything else the main filters can't.
 

TheFool

Large Fish
Apr 19, 2006
323
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#5
That water report looks very good. Look at the numbers for phosphate P and copper Cu and if they're both very close to zero then frankly you can consider using your tapwater. I use mine - if you live in a metro area, or have rubbish water then RO is a big improvement, but they're not always essential. My nitrate goes up a bit at times tho', but it's not much of an issue.

The reason that nitrite/nitrate are quoted as a pair is that the many test kits can't tell them - they can do nitrite, and nitrite + nitrate, but not nitrate alone. As to what's a bad level of nitrate, well thats a long story, but anything above 5 gets risky.
 

TRe

Elite Fish
Feb 20, 2005
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ft. lauderdale
#6
on a tank that small i wouldnt be conserned with a r/o unit unless it becomes an issue.... at most grocery stores u can get r/o outa the machine just bring yur own jugs ;) on a 20g tank 5g water change is pretty good so just pick up a 5g jug and itll cost less than $2 to fill it up
 

Avalon

Superstar Fish
Oct 22, 2002
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#8
I am really happy with my RO unit. I never installed the DI. I use it for both drinking and my tanks. I like the control I have over water params. It's become one of those items I really value in this hobby, unlike a UV sterilizer (useful, but totally unnecessary).

As for measurements between RO and RO/DI, RO/DI should read very near zero when testing TDS. My RO only, with a taste filter that raises TDS slightly, reads around 80 TDS, which is still really good. About the only thing left in the water are the charged ions, which I don't think really hurt anything. I have tested KH, GH, nitrates, and pH, and KH/GH/nitrates are zero, while the pH is a perfect 7.0. While TDS is a pretty worthless measurement inside the aquarium, it is useful when testing RO water.

Having one for a 20g tank is overkill, but if you would like your own 'endless' supply of Dasani, I would recommend it. And definitely if you plan on using RO water with multiple or larger tanks.
 

1979camaro

Ultimate Fish
Oct 22, 2002
5,862
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San Ramon, CA
#9
I have RO/DI simply because it was virtually the same price ($11 extra) as getting the standard RO unit. I am really glad I have it as well; I have noticed a dramatic improvement in the health of my tank.

I followed Lotus' advice and ordered from The Filter Guys and I would recommend them if you decide to get a unit, but as others have said, on a tank of that size it is probably not necessary.
 

Joe Fish

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Apr 21, 2006
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#10
I ordered from the filter guys as well and so glad I did. My TDS meter reads 0 after the DI cartridge. I got a bypass so I can make drinking water that bypasses the DI. For smaller tanks I agree using tap or buying RO from a store would work just as good.
 

#11
Hmmm....well all of our water is well water from the pajarito plateau, and the water report i found was very bland. But my dad is the leader of the water and hydrology group at LANL, he says he can get me a full report on nearly any mineral, so ill check on that. well im glad i dont NEED to buy an RO unit, but i do plan on making it a fairly.......for the loss of words......"filled" tank. Many corals i plan on. Would it be better in the long run to get one? i just confused my self. Start over. If u were me, u knew u had well water, .4 ppm nitrate and nitrite, lets say 25 gallon w/ 10 gallon sump, what would u do?WWUD?

One more question, what are the steps in switching from tap to RO, say i got more tanks, could i just replace alll the old water with RO or should i do it slwoly? Thanx for u r help and patience. and my bad spelling...
 

Lotus

Ultimate Fish
Moderator
Aug 26, 2003
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#12
I'd say that if you're serious about corals, it would be a good idea to get an RO/DI unit, or buy RO from either the LFS or a water machine.

You can always use the RO (not DI) for drinking water for the family :) It works out cheaper than buying bottled water (if you do).

The quality of your water has a direct effect on your corals. If the water is less than perfect, your corals will probably also be less than perfect.
 

TRe

Elite Fish
Feb 20, 2005
3,645
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ft. lauderdale
#16
whether or not u decide to buy the r/o unit id still use r/o regaurdless to save from headaches down the road...thats what i was saying..in a tank that small it wont be too much of a pain to get a 5g jug filled where ever u decide to get it.... personally i use r/o from the machine at the grocrey store for top offs and as far as water changes i get my salt water from a lfs for .50 a gallon btw i use natural sea water ;)
 

Joe Fish

Superstar Fish
Apr 21, 2006
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#17
If you do not start out with ro/di you can just switch to it. When I switched I just did my normal water changes and topoffs. Eventually my nitrates and phosphates went to 0. In the long run you will save by having a ro/di. For a small tank you could probably just buy it as you need it. Top offs won't be that much until you get good lighting and it will also depend on how covered the tank is.