RO/DI system good or bad for reef tank??

Hi, someone can tell me the pros and coins of using a RO/DI system into a reef tank.

Can someone explain how a RO/DI unit works and what the differnce is between a 2 canister or 3 and what it is taking out of the water that can harm your tank? Ive always gotten free RO/DI but recently moved away from my source and have just been using dechlorinate tap and my tank appears to doing fine, but I know I eventually want to get a RO/DI I just dont know what kind?

there's also some good videos on youtube

Yup.

Edited by bfessler - October 21 2009 at 6:50pm

But it is true that RO/ID system will affects the level of trace elements, magnesium and other minerals??

In this hobby, there is no need to buy a water purification unit that includes the final step of de-ionizing. Reverse Osmosis water is perfectly fine for a good reef setup. From that point what makes more of a difference is to have 1)the biological filtration working at top capacity, 2)the water circulation at maximum efficiency, 3)the lighting matched to the organisms kept and 4)the Alkalinity, Calcium and other water parameters in balance.

Edited by Mark Peterson - October 21 2009 at 8:19pm

RO is the way to go for our reefs IMHO. It really helps keep nuisance algae and other stuff from taking over our reef tanks by limiting nutrients introduced. If you're not worried about algae, then I don't know if it matters.

So to answer your question, the Pros are:

1. Algae nutrient removal (helps to reduce the hair algae, cyano, and other stuff).
2. Harmful chemical removal, such as copper compounds.
3. Salt mixes are geared for it.

Cons:

1. Removes helpful chemicals, such as calcium and magnesium.
2. Costs money.
3. Adds to maintenance for filter replacement, etc.
4. Wastes a lot of water, even with a permeate pump.

I think DI isn't necessary for a reef. Maybe I'll change my mind at some future time, but I know plenty of people who don't use it.



There are some people with water that has 200 ppm TDS and don't use RO at all. It all depends upon what chemicals make up that 200 ppm.

I think TDS plays a huge part in all this, So let me ask this does anyone and i mean anyone know what there TDS number is and in what PPM of the minerals ar left or even whats left over? I would have to say i bet almost no one does. To say that your friends aquarium never needed any supplement doesn't mean this aquarium had all the trace elements it needed, There are many factors to consider. By the looks of the aquarium picture above there doesn't seem to be a lot of sps/lps nor calcifying corals, with mushrooms and leathers and most things in that aquarium there is no demand for calcium,alk,mag so i would say that this is very miss leading to the average hobbyist. There is also another huge problem with kold steril as the post below mentions, Unlike r/o units where you use the TDS to know when its time to change filters kold steril units need to be changed by how much water is used threw, So you must keep track of every gal gone threw this unit to know when it's time to change the filters no testing nothing!!


Here is good post i found,

Kold Steril and R/O units are two completely DIFFERENT systems,
operating on different principles and producing different results. Each
one is supposedly very good in what it does, which is different.

Kold Steril, as the name implies, offers "cold sterilization" i.e. it
passes the water through a 0.2 micron filter membrane, removing 99.9% of
all "bugs" (except viruses). The product water is bacterially sterile.
If a bit of chlorine was added at the outset, then most viruses would be
also inactivated.

The Kold Steril SYSTEM has an ion exchange membrane and activated carbon
unit added. They DO remove some heavy metals and organics but not all. However, on
the Kold Steril site
(http://www.marine-monsters.com/front/products/koldsteril.html) I could
NOT find the capacity of the system, i.e. what volume of a given water a
cartridge will process, just a warning that the manufacturer's
directions on replacing spent units must be followed to obtain the
advertised results. That gives me something to think about!

If you need sterile water, with essentially unchanged water chenistry,
Kold Steril is probably the unit of choice.

On the other hand, there are several different R/O units with different
membranes, that produce different results. All of them pass water, under
pressure, through a very tight membrane that lets smaller ions/molecules
through, rejecting the larger ones and flushing them out. The "flushing"
part generally uses 3-4 times as much water as it produces as product.
The rejected water can be used to water your garden or for hardwater
lowing fish (also good for snails and Daphnia), but it is, essentially,
a waste stream.

Depending on the membrane, temperature, pressue, etc., generally up to
95+% rejection of divalent cations can be achieved. The product water is
VERY SOFT, almost like distilled water. For most uses minerals have to
be added (or raw water blended back in) to obtain the hardness one needs
for fish to live in it.

So, if you need soft or softer water, R/O is the way to go!

REMEMBER -- the two systems are NOT interchangeable -- they produce a
different product!

 

Burt, Kold Steril doesn't remove all bad stuff, Yes it removes some but like i said above you don't know what you are getting when it comes out. TDS plays a big part of water quality so unless you know ( which i don't thing any of us really do) what PPM of minerals are before and after the kold steril unit then TDS is the only way to ensure water quality. It is crazy to think of leaving things up to chance.  I think R/O with a good salt that has trace elements in it is a far better solution then not knowing whats coming out of a kold steril unit...

Here is something to think about.

In Las Vegas where water is a premium, At Mandalay Bay and at Caesars palace there whole aquarium and shark systems use R/O water If Kold Steril was a better way to go why wouldn't they be using this?


Edited by FIRE SHRIMP - October 22 2009 at 10:50am

Eric, you slay me.