Using Rain As Water For My Tank?

[BubblesLotsOfBubbles]

I can indeed. I used a simple daphnia test for toxicity. Largely involved sticking daphnia in the water and making sure that they don't die. If they do, test the water to see if there's an obvious cause.
 
http/ei.cornell.edu/toxicology/bioassays/daphnia/environmnt.html
 
Some introduction to the idea there.
 
Water was fine until one day when, I found out later, a local farmer had sprayed his crops with his new machinery. Daphnia died pretty much on contact and ammonia levels were off the scale. Sadly the fields are right next to us, so if you're out at work when they do it, you get a hit to your roof without realising. You can get devices that allow the first flush of water to go down the drain, but that didn't save me from that one. I'd started testing more rigorously after having some problems that turned out to be caused by a slug falling into the tank and dieing.

 
Thanks for the reply.
 
Looks like I was being a bit naive I guess and now it seems like a real risk of comitting to a single water supply that could be made redundant at a moment's notice. When I look at the water I collect its lovely and clear so there was a heck of a temptation to use it and get those acid loving spp I could not keep previously.
 
I later read it can take a long time to cycle an acidic tank too, so all in all I think I will give preference to tap water. Not got a test kit just yet - still working on my tank stand but I'd expect that to be more consistent, pest and disease free, even if it is higher in pH and salts.

 

[Gruntle]

I thought of using rain water but the pH was markedly different from tap water (tap water was 7.6, rain water was 6.5). I figured with the possibility of contaminants (living in a city meant the chance of pollutants from the roof) I decided in the end to stick with tap water.

 

[Alasse]

I used rainwater for a number of years, thats all i had. I was from a concrete tank so it had really high PH, but otherwise was no issue at all.
 
I now have access to it again and am debating dumping the current 3ft water and adding rainwater instead.....i would love to keep a couple of discus

 

[Tongue_Flicker]

Rain comes from clouds that move all over the skies all over the country. Make sure to test it for atmospheric pollutants first!

 

[TallTree01]

How could ammonia get into rain water? Nothing living it I assume. As pure as it gets.

 

[DrRob]

Lots of things get into rain water. Partly by absorbing atmospheric pollutants (as in acid rain), but mainly by the method of collection. Generally we're getting it off the roof of a property which can wash all sorts of things into the supply, ranging from dead leaves to dead animals, along with animal droppings, plus anything any local farmers have sprayed that landed on your roof, pesticide would be the nightmare scenario here, but fertiliser will be loaded with unwelcome chemicals.

 

[BubblesLotsOfBubbles]

After 'waking up' to the potential problems rainwater may give me, I have noticed twice this week when coming down the street where I live, the smell of smoke in the air. Who knows what other danger signs I'd miss while I'm in town or alseep etc.
 
Result: I am now more pleased to know I'm going with tap water than I was when I first thought "Cool I can use rainwater off my greenhouse!".

 

[CSnyder00]

A lot of people use rain water for GBR's because of the acidity. Acid rain is very common and it's hard to get acidic water here in Pennsylvania. Most of my tap is 7.4-7.6. Were I was in my rental before, I actually had readings at 8.0+.