Is DI/Distilled water ok for a fresh water tank?

[TurboFish]

New here.... Planning on doing a salt tank in the future with an RO/DI unit. But for now I have a 10 gallon fresh tank and only tap water. I keep getting this brown stuff forming on the plants and rocks. I'm assuming it's algae, and I'm also assuming my tap water is pretty bad which could be contributing to it. I have an algae eater, and he does a good job at getting everything he can reach. But it's still building up in the corners or hard to get areas. Anyways, I have a source of Deionized/Distilled water at work. Limitless supply basically. Is it safe to use that instead of tap water? I'm planning on doing a water change tomorrow but want to make sure first.

Well, maybe I should rephrase. Of course pure water is safe. BUT, do I need to add any chemicals or minerals to it to properly support the fish? I've been reading up a lot on salt tanks and those apparently mix in all the necessary minerals when you add the salt mix to the RO/DI water. Is something like this necessary for a fresh tank?

Thanks,
Brian

 

[tricksterpup]

I personally think you should be fine. When I was in college and working in the bio dept ( I was raising fat head minnows) we used Distilled water and never had to add anything. If you mean like adding salt to the water or any nutrient based product? the answer is no. Most fish are fine in clean pure water just do your water changes with this Distilled water. In time your water should be fine.

jim

 

[PumaWard]

It sounds like you have an over abundance of nutrients in your tank, like Nitrate. I wouldn't think it was your tap water, but have you tested it with your ammonia, nitrite, and nitrate test kits?
If it gives a positive reading on any of those, then it could be a contributing factor.

May I also ask what kinds and how many fish do you have in your tank? How often do you do water changes? Do you have any live plants? How long has your tank been set up?

I wouldn't use Distilled water personally, especially since your fish are used to your tap. Distilled water lacks pH buffers, generally kH, which keeps your tank from having huge pH swings. This creates a less stressful enviroment for your fish, and therefore they will be happier and healthy.

HTH

 

[TurboFish]

tricksterpup: No of course I would not add salt to a fresh water tank. lol What I was referring to was that for a salt water tank, the salt mix also has trace elements in it that are beneficial to the fish/corals. So what I wanted to know was if adding trace elements to a fresh water tank was also necessary where the water source was pure (ie: lacking any trace elements).

Puma: Yes, I probably do have too many nutrients in the tank. I assumed that was from the tap water. I have no idea what the TDS is, but I will be getting a refractometer at some point. I do use water conditioner, but that only neutralizes chlorine and chloramine. Does not remove phosphates and other things that algae thrives on. Here's the run down on the tank history....

I bought this tank for my son to have in his room (Daddy gets a 90gal reef tank soon hopefully! ). We started out with two Black Mollies after the tank was up and running for a week. Tank began it's cycle. But lasted for over a month without any sign of amonia/nitrite lowering. I think amonia was 1.5 and nitrite was 2.0 or something. Anyways, slowly algae started to grow on everything. Nutrients were probably really high at that point because the fish were NOT active AT ALL. They would hide in the rocks all day and would hardly eat either. I backed off on the feeding to just a tiny pinch once a day. Maybe it was too little too late though. Tank was so bad (algae wise) that I had to basically start over. I drained the water right down to the gravel, cleaned EVERYTHING in the tank as best I could (old tooth brushes) and refilled. Unfortunately, before I tore it down we lost one of the Mollies. He was the one that would not come out of the rocks at all. He might have starved himself. The other one would come out for a minute or two to nibble on some food. But that was it. Anyways, after it was back up, we got an algae eater and two Neon Tetras. The Molly that survived was extatic to get new tank mates! He was swimming around and looked to be doing much better. He hangs out with the algae eater sometimes, and even has picked up his habbits of munching on stuff on the gravel and rocks! Oh, I also upgraded filters from a Whisper Mini to a Penguin 125 with BIO-wheel. I was hoping the bio wheel would add to the beneficial bacteria and hopefully keep the amonia/nitrite levels in check.

Well, things have been going MUCH better. Amonia came back up to about 0.5, but last time I checked (two days ago) it was on it's way back down. Yeah! Nitrite was around 1.0 I think and should be going down as well (gona check tonight). Nitrate is around 8 to 9. I'm still getting some algae growing in the tank though. When I do the water change tomorrow I'm going to take out some of the plants (oh these are fake btw, no live plants in the tank) and scrub them again. But I want to keep this stuff from coming back! That's why I was thinking of using a better water source.

Sorry for the book! lol But that's how it's gone so far.

Brian

 

[TurboFish]

BTW, one thing that's odd is the pH seems to keep going up. I'm trying to keep it at 7.0 but it likes to slowly climb up to 7.2 and then 7.4 and even higher if I don't keep on top of it. I add "pH Down" to it every once and a while, but why is it doing this? Straight from the tap, I think the water is 7.4

Oh, and one other thing (Sorry! )... before the teardown the water had become very cloudy. It looked pretty bad for sure (cloudy water, brown stuff over everything, etc.). But since then, the water has been crystal clear. So it's definitely doing a whole lot better this second time around, but I still would like to keep the brown stuff away!

 

[OrionGirl]

Instead of using exclusively DI/RO water, you will probablyhave better results using a mixture with tap. This increases the water's ability to buffer, while diluting any toxins or negative chemicals like phosphates and silicates, both known to cause algae issues. Using just the straight filtered water, your pH won't be stable and prone to crashes.

pH down is a no-no, especially in a cycling tank. It's effects seldom last for very long, and a fluctuating pH is much worse than a stable one that is not in the 'ideal' range for the fish. Also--look at your fish. Mollies prefer hard water with a high pH, neons like the exact opposite. Somewhere in the middle will be best for the mixture.

The swings right now are the result of the cycling process. As the bacteria become established, this will settle down and can be addressed through regular water changes. Extremely large water changes require special precautions, as does disturbing the substrate.

 

[PumaWard]

Because your tank is cycling you are having a algae bloom, which is completely normal for new tanks. I would recomend getting some live, easy to care for plants like java fern and java moss which will take the nutrients away from the algae.

Since you are cycling with fish, you should be doing 25-50% water changes every day. Do not change all the water and clean the gravel as this will kill off much bacteria that may be in your tank. Any level of ammonia or nitrite that reads above 0 on your test kit is harmful to your fish. I would put 2 teaspoons of table salt in your tank, as this will lessen the toxicity of nitrites and help improve gill functions, don't put anymore in though, as it may harm your algae eater (I am guessing that it is some specie of pleco?).

Cycling can take as long as two months, sometimes more, in a new tank. Also, the cloudy water is also normal, as this is a beneficial bacterial bloom do to the over abundance of nitrites and ammonia. So, although it's ugly, it is a good thing.

One thing you may want to consider is taking a cupfull of gravel from an established tank (not from the pet store though), but make sure that the tank you are getting it from has been set up for some time, 6+ months, though a year or more is preferable. This will help to shorten your cycle by introducing bacteria into your tank.

As far as your pH, I wouldn't do anything with it. Most tropical fish can adjust to pH levels between 6 and 8 without any problems. Keeping your pH stable is more important than it being neutral.

HTH, good luck

 

[TurboFish]

Well, things are looking better in the tank now. Saturday, I cleaned the tank some (cleaned the plants, used a gravel cleaner, etc.), and did the water change. I changed about 2.5 gallons. 2 gallons of which was the DI water, the rest tap. Here's the param. just before the water change/cleaning...

pH 7.2
Ammonia 0.2
Nitrite 2.0
Nitrate 9

Ammonia was going down, but Nitrite was heading up. Yesterday I checked the params again and it's much better...

pH 7.1
Ammonia 0.1
Nitrite 0.4
Nitrate 10

Ammonia is almost gone completely, and nitrite is quickly disapearing too! I may still have a slow growth of algae.... not sure yet since I cleaned the plants last weekend. Will know for sure in a week or so. If it's still there, I might try your suggestion of getting some live plants to help remove the nutrients from the water.

Thanks for the help!
Brian