Reverse osmosis water & my aquarium

[JCS]

For about a year now, when I do water changes, I replace aquarium water with reverse osmosis water from the drinking water store. Am I doing the right thing? My fish seem to like it (10 neon tetras, 2 gouramis, 2 platies, 1 chinese algae eater), but once when introducing five new neon tetras to my aquarium, two of them were dead the next day.


Any advise is good advise!

 

[Copper]

Check your water for ammonia, nitrites, nitrates, ect...make sure it's all on the level. Neons can quickly fall prey to changes in water conditions and stress. Likely they were a bit overloaded from the move and died off. If all of your other fish seem healthy, I don't see a problem using the reverse osmosis water. IME, losing a couple of new tetras from the LFS is somewhat expected.

 

[N8DOGG]

RO water is better for the fish than tap water. It takes out a lot if not all of the "bad" things (sorry is friday I can't think right now) I know its better to use it and it might have been an aclimation(how did you do this) or stress induced death. sorry for the loss.

 

[Cearbhaill]

I would probably recommend mixing RO water with at least a portion of tap water unless you are needing very, very soft water- and even then you will need to add trace elements. The RO is missing minerals that are necessary- and I have to ask- what are your hardness levels? How do you keep your pH from crashing?

 

[daveedka]

RO water definately has it's uses, and it is good pure water. If you have an issue with tapwater, it is a viable option. However it is devoid of many trace minerals and is d3evoid of KH. Therefore it can cause problems as well. I agree with Cearbhaill that mixing is the way to go. Assuming you have no plants, the traces arewn't as critical, but there still needs to be some buffer and traces available in the tank.

As far as the neons, being new fish there are many possibilities, so I wouldn't worry a lot. I do agree that you should run some tests, and make sure everything is in order including a ph test. The ph test will tell you if your tank is kh defecient. My brothers tank has a kh of 0 and the ph stays around 5.6- 6.0. I imagine if he added any new fish they wouldn't last long.
Dave

 

[JCS]

First off, the tap water in southern california tastes like cardboard on a good day, so i highly doubt it is good for aquariums, but I may be wrong.

As for the pH, I just tested it, it's at about 6.7. Later today I will take a water sample over to Fish 2000 and have them test it (I have not yet purchased a complete test kit).

 

[Seaman]

i would guess two things for the deaths, either the difference in PH from the LFS to your tank shocked them, or being that you ONLY use RO water, putting healthy fish in will immidiately begin to leach trace minerals OUT of the fish, so it could theoretically have killed the fish if lets say all the iron was leched out of the fish.

the way it works is if the fish have less iron than whats in the water, then everything wants to "equal out" and the iron is "absorbed" into the fish. Also it works in reverse, if the water (RO water) has had EVERYTHING removed from it, then everything tries to equal out and things are leached out of fish.

"Osmotic pressure can be best described as the water trying to dilute the fish's body until both sides are equal. Freshwater fish therefore have to constantly eliminate the water - mainly through respiration and urine"

theoretically that can cause major problems for fish, and put them in osmotic shock. Its not usually the actual loss of these trace elements that kill the fish its the high osmotic pressure they experience when the water is trying to "suck" these elements out of the fish.

 

[ChicoRaton]

Seaman, I believe you misunderstand the process of osmosis. The water doesn't try to "suck the elements out of the fish". Only water passes through the membrane. Therefore the water tries to dilute the elements inside the fish, and the fish excretes the excess water. I do believe you are correct about the ph and hardness shock killing the new fish so quickly.

What I'd do to your RO water is get something like kent RO Right. it'll add all the trace elements and buffers you need. very easy to use. Be sure to phase this in slowly though, as your fish are now acclimated to the RO water.

If you want a free option, you could dilute your tap water with RO water too, though "RO Right" is specifically forulated to be "right" without an imbalance of one mineral. I've never used it myself, but I've heard it works well.


HTH

 

[daveedka]

First off, the tap water in southern california tastes like cardboard on a good day, so i highly doubt it is good for aquariums, but I may be wrong.

As for the pH, I just tested it, it's at about 6.7. Later today I will take a water sample over to Fish 2000 and have them test it (I have not yet purchased a complete test kit).

Please understand, I am not saying either way whether or not your tap water is acceptable, but if it isn't and you use RO only, there are things you need to add. 6.7 ph indicates that things aren't too bad in your tank since that is about the range that RO water tests at. . In other words no crash due to biological processes. However it does indicate a lack of anything in the water. Either way it would be best to add some things back in. the RO right mentioned above is often reccomended.

As far as the flavor of the tap water, I'd reccomend downloading a report from the local water company or asking them for one if they don't have a website. Flavor like clarity doesn't mean a lot. I'm sure your tap water doesn't taste as bad as the water in your aquarium. The local water company can give you test results from which you can make you decesions, and possibly save some money on RO and some work for yourself.
HTH
Dave