View Full Version : Reverse Osmosis Water?

02-02-2007, 03:41 AM
I have an RO system for drinking water. Do I want to use this water for my fish? I am running 1 trash, 2 pre-carbons, RO membrane, and a post carbon.

02-02-2007, 04:13 AM
ive heard that r-o water is bad for fish

02-02-2007, 04:25 AM
ive heard that r-o water is bad for fish

Ive seen Dr. Fosters and Smith sell R-O filters in their catalouge

02-02-2007, 04:25 AM
Thanks, my first instinct would have been to use the RO water.

02-02-2007, 04:44 AM
I always saw nothing bad with r.o, but some people say dont and others say its great. It just removes some chloramines and chlorine, so I actually dont see whynot use it

02-02-2007, 12:15 PM
RO units remove chlorine and chloramine but I think also removes heavy metals and trace minerals. What you get is PURE water. It is not bad for fish but it is not advisable to use 100% RO due to there being no trace minerals. It would probably also cause ph to be far too low. A lot of aquarists swear by it for keeping and breeding soft water fish (it does give you soft water). My understanding of how they use it in aquariums is that it is mixed with declorinated tap water to add back some vital mineral content. It is mixed in varying percentages to give the desired softness and ph. 50/50 RO and tapwater seems to be a fairly common mix. I have never used it though because I am on a water meter and I have read that RO units use a ton of tap water to get only a small amount of RO.

02-02-2007, 02:01 PM
What I understand it that you never start a freshwater tank with RO water only...

...because it's pure it doesn't contain essential elements that the fish need, and without going into a long discourse about osmosis and what not, fish will die in pure water...

...once you have a tank established, RO water is fine for partial water changes or topping off the tank...

OR...if you do happen to start a freshwater tank with RO water, you need to cycle it artifically...ie. add ammonia...and then be sure that the water quality is established before adding fish to it...and you do need to add a bit of salt...

Marine aquariums will use RO water to start a tank...esp. since the water quality is more important they want the initial water pure...BUT they then add salt to the water before they start to cycle the tank...so the process is a bit different...

02-02-2007, 02:17 PM
RO water can be very useful, especially if you are keeping fish that like soft/acid waters or if you have contaminants in your water that you want to get rid off.

The problem with RO water is that it takes almost all of the elements out of the water. Essential things like calcium, sodium, magnesium, iron etc... all get their concentrations reduced with RO treatments.

Now, if you want really soft water (like for a black water system) then that's not a problem. But for most aquarium setups, it's not ideal. You can either add dechlorinated tap water to get the levels back where you want them or you can buy salt mixes to add to the water to get things to certain levels. It depends on the quality of the tap water mostly, but it's usually sufficient.

02-02-2007, 02:28 PM
i use r.o. water in my aquarium. it's the most pure water to date. you do, however, have to replenish the trace minerals vital for the life in the aquarium(plants/fish/inverts) i use 50%r.o./50%tap water. you also have to replace the minerals to get the ph to the range you are trying to establish. R.O. WATER IS NOT BAD FOR FISH! you cannot use straight r.o. water though. make sure you test your water that comes from the home r.o. unit you have before introducing it into your tank/tanks. --jeff

02-02-2007, 10:39 PM
sooooooooooooooooooooooooooooooooooooooooooooooooo oooooooooooooooooooooooooooooooooooooooooooooooooo ooooo complicated:confused:

02-02-2007, 10:42 PM
sooooooooooooooooooooooooooooooooooooooooooooooooo oooooooooooooooooooooooooooooooooooooooooooooooooo ooooo complicated:confused:

it's not as complicated as it sounds. the most complicated thing for me when i bought the unit was figuring out the best location for it. i mounted it above my shower. i know it sounds like a weird place, and it probably is, but any overflow will just go down the drain instead of on the floor. i also picked the shower because of the water source and the water pressure. r.o. filtration's ideal pressure is 65 p.s.i.

02-03-2007, 02:02 PM
I have to agree that RO water is not bad for fish. I have never used it but know of a couple that do. One for their freshwater aquarium and the other for their impressive saltwater collection. Both have had excellent results in fact, the saltwater person swears by it.

02-03-2007, 05:22 PM
I guess the verdict is that it depends on your situation. I guess I will start by testing both the RO water and my tap water and go from there.

Thanks everybody