Hi All

So I was wondering if there would be any implications in filling/water changing a tropical freshwater tank with rain water rather than condition tap water. I am assuming rain water would be better as it is natural and probably full of healthy nutrients for fish and plant.

What are your thoughts?

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Q-man.

5 Gallon Tank
Java Fern, Driftwood
Fish & Chip shop ornament

In the process of constructing a 22 Gallon Tank.

first of all let me state that I use untreated tap water and just do top offs in my heavily planted freshwater and marine (with macro algae) systems. Just to give you a reference point.

Sure pure rain water may be fine and possibly a little too "fine" as some things like calcium carbonate and magnesium is actually beneficial in small quanties in replacement water.

But to me the real problem is collecting sufficient rain water without adding toxins, bad bacteria, parasites and so on. After all you have to have some kind of storage container and collection device. So the water runs over all that and then is stored as well.

So to me it is better to use tap water (in some cases ro/di filtered tap water) because that tap water is specifically treated to prevent problems for us human drinkers.

But still that's just me and my


.02

Rain water is a great way to initiate spawning in a tank.Conditioned tap water(which is highly suggested)is fine for normal use and as long as you remove the chlorine and chlorimine,most everything else will be at minimal levels and some will indeed be beneficial to the fish and plants.

BTW,as a quick note,placing unconditioned tap in a tank is pretty painful to the fish and sometimes fatal if they are in contact with enough.Look at it this way.You are pouring essentially bleach like water into the tank....

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http://bountifulbettas.blogspot.com/

"Come to the dark side....we have cookies...and filters/heaters/and water changes!"

i would agree with bev, and i know several members here do use rainwater. My understanding is that it is very soft usually, and using it entirely may present issues with pH being stable.

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"Being ignorant is not so much a Shame, as being unwilling to learn".-- Benjamin Franklin

Rainwater would work fine so long as you ae not in an urban area. Rainwater would collect any atmospheric pollutants, like NO2 or Lead, in an intense urban area. Distilled Water is the same as rainwater but doesn't have the pollutants in it.

I notice you have a very small tank, so rainwater will be easy - too easy.

it is only good for rainforest fishes, to begin with. A molly, guppy or other fish from a mineral rich environment will die in it while a cardinal, a neon or such will be delighted. You'll have to find out the origins of your fish.

It's unstable, chemically. Pure rainwater is not good, and you'll need to add some minerals for it to support life. I had 140ppm GH water in my old house, and to breed rainforest fish, I had to add 20% tapwater to 80% rainwater or the tank crashed and became too acidic.

I lived within sight of the highrises downtown in a city of 3 million, and collected up to 40 gallons on a good rainstorm. It's good to store it as a drought would mean chemically different water for your fish, and stability in water is a goal for every aquarist. You can't jump around between water sources and not kill fish. I didn't save any water for the first ten minutes of a rain, just to make sure the water coming down the eaves was clear of bird droppings, etc.

Just drop the natural idea. Nature is very complex, and rain that falls on limestone is naturally different from rain that falls in a peat swamp, and fish have evolved in very different natures. Water is a blank slate - no nutrients, and what it picks up depends on what it falls on. Pure rainwater is absolutely barren.

I use rainwater...even when i had my african cichlids. Never had any issues with, and still dont. I dont add anything to it

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Major tank shuffle happening!!

It depends where you live, i wouldnt use rain water near a big city or industrial area. Your going to get the chemicals that are in the air in your tank.

Alasse - that is really interesting. I had a lot of trouble with pH crashes when I used straight rainwater. Do you think yours was picking up some buffer from the substrate?
Mine would test at 0 ppm, pH 7.0. It really picked up minerals fast.

It makes you think - it's a good hobby for that.

The substrate is inert

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Major tank shuffle happening!!

I see an experiment coming...