Newbie Ro water question
 

This sounds really stupid. But what is it? ??


I have just been using tap water and mixing it in a 5 gal bucket and letting it sit for 24 hrs before i add it for water changes.

Copied from About.com:Chemistry.


Diffusion is the movement of molecules from a region of higher concentration to a region of lower concentration. Osmosis is a special case of diffusion in which the molecules are water and the concentration gradient occurs across a semipermeable membrane. The semipermeable membrane allows the passage of water, but not ions (e.g., Na+, Ca2+, Cl-) or larger molecules (e.g., glucose, urea, bacteria). Diffusion and osmosis are thermodynamically favorable and will continue until equilibrium is reached. Osmosis can be slowed, stopped, or even reversed if sufficient pressure is applied to the membrane from the 'concentrated' side of the membrane.
Reverse osmosis occurs when the water is moved across the membrane against the concentration gradient, from lower concentration to higher concentration. To illustrate, imagine a semipermeable membrane with fresh water on one side and a concentrated aqueous solution on the other side. If normal osmosis takes place, the fresh water will cross the membrane to dilute the concentrated solution. In reverse osmosis, pressure is exerted on the side with the concentrated solution to force the water molecules across the membrane to the fresh water side.

Reverse osmosis is often used in commercial and residential water filtration. It is also one of the methods used to desalinate seawater. Sometimes reverse osmosis is used to purify liquids in which water is an undesirable impurity (e.g., ethanol).

So basicaly its just more pure water with less crap in it. lol. srry im realy new to all of this. i had freshwater tanks my whole life. just basicaly did ph tests on my freshwater and did water changes never had anything to complex. Are the RO set ups expensive? is there cheaper diy systems you can do?

Not trying to hijack but I was just wondering; if reverse osmosis is used in residential use then why do people do this themselves?

For all my tanks water changes I dont use anything, I just mix a little bit of hot and cold water and then top off. No algae problems at all yet.

you must have good water where your at then eh? Im having abit of hair like algy breaking out now. :S

[quote=if reverse osmosis is used in residential use then why do people do this themselves? QUOTE]

Because it's not at the municipal level, the units are added privately.

If you can get good enough water out of the tap then great! Just keep in mind that water quality can swing greatly with winter run off, heavy rains carrying pesticides and extra chemicals added to the water supply to combat the poor water. If you aren't having any phosphate problems at the tap source then maybe your algae problems are being caused by excess feeding. I would run a few tests before buying an RO unit, although you :wink:can get a descent RO/DI set-up for around $200 new.

As I posted, that was copied from another site. I would highly recommend using RO water. IMO of the tanks i've seen in person there is a noticeable difference between the ones that do use it and the ones that don't. The better water quality does make other things alot easier to try to manage.

It's a good idea to get informed as to the quality of your tap water if using it directly for your system. That's really the best way to determine what kind of filtration/treatment is appropriate for the water you're using for your system. I used tap water for close to two years and have experienced an improvement in my system since switching to RODI water just over a year ago. The TDS (total dissolved solids) in my tap water is typically around 210. I reviewed the documentation available from the regional district to see where my tap water comes from and what is in it. Most water suppliers, whether private or city/municipal will have this info available on line these days. I've heard that you folks on the coast, Vancouver etc. have very low TDS to start with from your source, something around 10. You can probably do without RO filtration with TDS that low quite easily, but it's still a good idea to find out what those TDS consist of. The thing about using RO water is that you're starting with a known element with virtually no contaminants when mixing up your salt water. Using tap, you never quite know what you're adding to your system that may contribute to undesireable consequences in the long term.

Find below a report on my local water from a few years ago. While it contains some good numbers for pH, calcium and a few other minerals beneficial to a salt water aquarium, there are traces of a lot of other stuff that I really don't want to take a chance on. The 1 micron poly pre filter on my RODI system gets gummed up substantially within a month or two of water changes. Another thing I've noticed since switching to RODI water is that my Alk is much lower than it used to be when using tap water, too low in fact, but my critters, especially GBTA have never looked better.

North Kalamalka Lake Intake Water Quality 2008
Water System: Greater Vernon Water
Source: Kalamalka Lake
Facility: Kal Lake Pumpstation
Sampling Point: Kal Lake Intake
Date: 7/14/2008
INORGANIC Results (mg/L unless noted)
Aluminum <0.050
Antimony <0.0030
Arsenic <0.0050
Barium 0.027
Boron 0.021
Cadmium <0.00010
Calcium 40.6
Chloride 5.38
Chromium <0.015
Copper <0.0030
Cyanide < 0.01
Fluoride 0.24
Iron <0.20
Lead <0.001
Magnesium 19.8
Manganese <0.0050
Mercury <0.00030
Molybdenum 0.005
Nitrate (as N) 0.069
Nitrite (as N) <0.010
Potassium 5.07
Selenium <0.0050
Sodium 18.4
Sulphate 51
Uranium 0.003
Zinc 0.011
PHYSICAL Results (mg/L unless noted)
Alkalinity (as CaCO3) 152
Colour <5 TCU
Conductivity 409 microS/cm
Hardness (as CaCO3) 183
pH 7.8
Total dissolved solids 238
Turbidity 1.0 NTU
UV Transmittance @254(%) 91%

your TDS is 238?!!?!?
i just tested mine from the tap and its 12

Your out of tap TDS is 12 ?!?!?!? You almost don't even need to use RO/DI :-) Or at least save some money and skip one of the stages/filters :biggrin:

I'm wondering if my tds meter is wrong. Mind u I'm walking distance to the dam

Is that a good or a bad thing? :biggrin:

Bet you thats wrong. I doubt a natural water body would be anywhere near that low. So much **** gets dissolved into the water so naturally/easily. (not trying to bash or anything lol but im just saying i think your meter is out to lunch, specially if thats from the tap).

And you think 238 is bad... My well water is 1200... and a friend of mine, his well water is around 3000! Haha. And our TDS meters are not wrong because those values have been tested in duplicate by different units!

Like I mentioned earlier, some of you folks on the west coast are blessed with very low TDS source water. I think it might be due to the fact that there's so much rain, which is quite soft water, and your reservoirs primarily collect rain water. Your TDS reading is most likely accurate. If your meter is a dual type, you can try switching the probes around to see if you get any significant variance in readings between the two. Or beg, borrow another meter to validate your own. And rejoice, your DI media, if you have it, will last a very long time.

One of the big advantages of a DI system is that is produces fairly consistent results which means you have a solid, year-round baseline to work from when it comes to the water you put in your tank.

Sometimes moving even a few blocks across town can give you different water and blam! algae bloom.

It removes one level of mystery in the hobby. I'd recommend you make the (relatively small) investment and get the filter.