Just done today's water tests and have to share the thrilling news. Not a trace left of all that ammonia I dosed the tank with yesterday, which means the ammonia chomping bacteria are in prime fettle. The nitrite levels are still poisonously high, but is there maybe just a hint that the purple colour in the test tube isn't quite so deep today as it was yesterday? No doubt at all that the plants have been scoffing some of the nitrates, because the liquid in the nitrate test tube is orange with just a hint of salmon, nothing like the bright pink it was last week.
Testing the water is less of a chore than I expected. The water turns such pretty colours. The low pH reagent drops can turn the water yellow (very acid) orange (quite acid) green (around neutral) and blue (on the alkaline side of neutral). For water with high pH there is a range that goes from yellow through orange to brown and then purple. The ammonia test turns yellow if there is no ammonia, lime green for trace amounts and then deeper and darker shades of green for as far as it can measure (up to 8 parts per million). I'm a fan of the nitrite test, it starts out duck egg blue, turns lavender when nitrite is detected, then violet and finally 3 increasingly deep and dark shades of purple, very pretty for a noxious water warning system. The nitrate starts yellow if the water is pure, turns marigold, then orange, then apricot, then a surprisingly hot shade of pink, which is as dark as I've ever seen it, though the colour chart that comes with the kit shows scarlet and then deep red for water containing 80 and 160 ppm.
Knowing what kind of water you have got takes a lot of the guesswork out of keeping fish happy and healthy. Most of the more ordinary tropical fish can adapt to poor conditions, but they tend to get stressed, which makes them open to infection, and their lives can be shortened by several years just by having the water a degree or two warmer than really suits them. Not that most of them seem to live very long anyway, there's even a kind of fishes that are referred to as 'annuals', like plants, because they are designed to live for a year, breed, lay eggs in the mud and die as the drought sets in and dries out their pools. Then when the rains return the eggs hatch and the life cycle starts again.
I read somewhere that one of those annual fishes was considered the most beautiful freshwater tropical fish, had a look for them on youtube and have to agree that the males are quite splendid. http://www.youtube.com/watch?v=6n3AEb1ftNI
but since they only live for a year you very rarely see any for sale, and they are expensive if you do find them. People who do breed them will sell you a bag of damp peat with some eggs in it, and you can have a go at hatching your own, which is what the person who made that youtube video had done. It all seems a bit like growing plants from seed, I'm sorely tempted.