Understanding Water

I've been studying water recently. Not just staring into my koi pond but trying to learn more about the science and properties of good water for koi. I thought I knew everything about the right water for koi and the processes going on and I do know enough to keep koi healthy but I was hoping to discover something more. It seems I got more than I bargained for as a quick search on Google for the properties and science of water chemistry reveals I was just scratching the surface.

Most people that keep koi know the Nitrogen Cycle inside out and the relationship between pH, and this is all we really need to know but I'm curious to understand the other processes taking place in a pond. I was never very good at chemistry or physics at school but my enthusiam to learn everything about koi has pushed me to at least try to understand it. That said water is an incredible substance with some quite amazing properties so when investigating it you feel that even someone like Steven Hawkins may struggle to comprehend all of it. Here is an excerpt that when I first read it I thought was a joke that they were going to give an explanation to in plain English, but no it continued for another 50 odd pages!

Water molecules ionize endothermically f due to electric field fluctuations caused by nearby dipole librations resulting from thermal effects, and favorable localized hydrogen bonding 567; a process that is facilitated by exciting the O-H stretch overtone vibration. Ions may separate by means of the Grotthuss mechanism but normally recombine within a few femtoseconds.

This was taken from an article about ionization of water which many koi pond products claim to interact with but which few people actually understand let alone explain. Even the scientists argue about some of waters apparently mysterious properties and reactions. I was going to write something poetic "like water is the stuff of life" but we've heard it all before and what's more interesting is the real truth about water, which when thought about is really quite odd. It's these odd things that makes life possible as we know it and the combination of hydrogen and oxygen, two common elements in the universe, form a compact molecule that easily recombines with others. Here is a website that lists 63 anomalies of water which can explain how odd water is far better than I ever could, but even some of the explanations made my brain fade. My favorites are:

• Liquid water can exist at very low temperatures and freeze on heating. Hot water may freeze faster than cold water (the reason hotwater pipes burst before cold)
• The density of ice increases on heating - up to 70K.
• Pressure reduces ice's melting point (anyone that ski's or climbs mountains can see this effect -more snow higher up)
• The speed of sound increases with temperature up to 74C.
• The refractive index of water is highest just below 0C (Best photos of your koi will be when it's warmest - Frozen in a block of ice or boiling water has less refraction but obviously your fish will have died by then:)
• Electrical conductivity increases in warmer water up to 230C (It's easier to electricute yourself in hot water, but don't try this!)

I could go on and on but this has little to do with keeping koi, although we all know about stratificaton of water as it gets colder, with ice floating in water because of the density change. The reason I got into all this is not only to gain greater understanding but also a number of people are quoting more and more supposedly scientific explanations which may or may not be true. One area which would considerably aid koi ponds is the possibility of aerobic denitrification. Recently a number of products and systems have claimed to reduce nitrates with bacteria to oxygen and nitrogen gas in highly oxygenated water. Apparently this has been used in marine aquariums but as yet I have failed to find a reliable report. This is something I'm sure will be of interest to all koi pond owners as a future development.