New to RO/DI

[Tennyson]

Hello,
I was just researching about equipment and came over RODI systems. I did a lot of researching but I just don't understand how these work and if id really need it for my tank?
Any help/summary/background info on these would be appreciated!
Also just wondring if id need one for my 46 gal, I've got a bit of an algea problem and purer water would be nice.
So are these things like for hanging on the back filtering the water? Or cleaning the water before you add?

Any links/specific models of these would be very helpful. Thanks!

[DC_40gallon]

Everyone needs ro/di water. Pure and simple it's the only way to go and that is what's probably causing your algae blooms due to the nutrients.

The work by taking cold tap wate. And putting it thru a chlorine filter, then a sediment filter then a DI filter and finally a membrane to get the last micro parts out.

The waste water with all the junk is sent one way and the other water goes into your bucket as pure water!

[Tennyson]

Ohh thiss. Okay thanks!
So are you saying that the main source of my algea problems and inpurities are from the tap water I use rather then my bioload? Or is the tap water a large part of it?

Any suggestions to a good and preferably inexpensive system?
I also read about DI? Being additional to the filtering for nitrates and phosphates etc, qnything on that?

[DC_40gallon]

Very much so. When the unit filters the water it takes out all nutrients such as phosphates and nitrates etc.

You truly get virgin water. They are a must in our hobby most of us have one.

Thefilterguys.biz

buckeyefieldsupply.com

airwaterice.com

these three are amazing sources and all three are sponsors here on reef central.

You can get a unit for your house that you can use for drinking water and tank water for $169-200 an that's everything included.

The unit pays for itself in a few short months in most cases with us.

Use ro/di water on your next water change by buying
it thru your loc fish store and do a 25-50% water change and you will see a huge difference.

We also usually promote doing a 10-25% weekly water change on saltwater tanks. Reason being is doing a change like that weekly will never let your tank build up the negative stuff that allows algae to grow.

[DC_40gallon]

I would recommend calling buckeyefieldsupply first and talk to Russ. He is a patient person who will walk you through everything in elementary terms for ease of understanding. He also makes the units himself to your needs so you get a qualityade in America unit.

[Homeytwist]

Have a look at these guys:
http://www.airwaterice.com/product/1COMPACT/Compact_75_GPD_Reefkeeper_RODI.html

Plus they have a promotion till the end of december where you get a free additional filter pack (minus the RO part).

[driftin]

...
I also read about DI? Being additional to the filtering for nitrates and phosphates etc, qnything on that?
I'm no "expert" but:
A typical 5-stage system will have a sediment filter, 2 carbon filters, the RO membrane, and then DI resin. A good RO membrane like Dow Filmtec will have a rating associated with it, say 94%. So if the TDS (total disolved solids) of your tap water is 100, the RO membrane is supposed to remove 94% of that. Leaving your RO membrane would be a TDS of 6. Then the DI resin should remove that - from 6 to 0.

The RO membrane should last a couple years if you change out the prefilters and flush it properly. The DI resin will not last that long, but it all depends on (1) how much water you make, (2) the TDS leaving the RO membrane, and (3) what you deem to be an acceptable TDS level for putting in your tank. As the DI resin is exhausted the TDS leaving that stage will gradually increase.

[Frogmanx82]

A quick explain on how the system works.

Stage 1 - a filter takes out everything larger than 5 microns or so
Stage 2 - a carbon block takes out chlorine and organics. The capacity for chlorine is much larger than the capacity for organics
Stage 3 - Reverse Osmosis filter works on the molecular level. Only water and small ions get through. Complex nitrates and phoshates are easily removed. RO units allow clean water to pass through and the "dirty water" has to be discharged to a drain.
Stage 4 - Ion Exchange resins exchange H+ and OH- ions for whatever ions come through the RO unit in order to deionize the water. DI resins have a limited capacity so their life is greatly extended by following an RO unit.

Units with more stages have doubled up on one of these 4 basic filtration methods.

[d0ughb0y]

Just to add, I recently tested my tap water, ro water, and rodi water and got this reading

tap water tds = 33 (yes SF bay area water has lower TDS than bottled water)
PO4 = 0.05 (measured using low range po4 meter)
RO water tds = 1, PO4 = 0.01
RODI water tds = 0, PO4 = 0.00

I can probably get away without the DI.

po4>0.03 will cause algae growth, therefore you will need an rodi unit.

This looks like a decent unit
http://cgi.ebay.com/RO-DI-REEF-WATER-FILTER-75GPD-AQUARIUM-REVERSE-OSMOSIS_W0QQitemZ230391392376QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item35a465a878#ht_2087wt_939

it looks exactly like that from purely h20, an RC sponsor. The wordings from purely h20 is exactly the same word for word as the ebay unit except for the h20 science brand.

[drewp808]

wow d0ughboy thats a lot of money youre paying for the DI to get it down 1 point. anyway
got mine form melevsreef.com

[d0ughb0y]

wow d0ughboy thats a lot of money youre paying for the DI to get it down 1 point. anyway
got mine form melevsreef.com

yeah I know. it was a $35 DI add on I got from BRS to add to a costco ro unit I already use in the kitchen for drinking water. the DI resin should last quite a while, I've only had it for 1.5 years.