So what is this thing called Good Water Quality?

There is a lot about good Koi pond water quality that we know about. There is even more that we don't know about.

Good water quality is thus something that we 'think' is beneficial to Koi.

Good water quality in a Koi pond

OK, so now you understand why we need good water quality but what is good water quality really?

I have defined good and excellent water quality as two different things. Good water quality will enable a Koi to survive in reasonable health. This is the state of most Koi ponds that I have seen. Very few demonstrate excellent water quality which is that in which a Koi prospers (you can see that they're happy).

It may be easier to start with what good water quality, from a Koi's point of view, isn't.

Good water quality is not necessarily crystal clear water. It may be, but crystal clear water is not a guarantee of good water quality.

Murky water may or may not be of good quality.

It isn't full of harmful bacteria. There are few pathogens and no poisons.

Now it starts to get interesting.

Good water quality is water that is suited to Koi. Of the things that we do know about, we know that good quality water will have a zero level of ammonia, a zero level of nitrites and increasingly a lower and lower level of nitrates. Nitrates up until recently have been thought to be of little consequence below 80 mg/l.

Koi produce two types of waste - inorganic ammonia and organic solid wastes. Both are dealt with differently as you will see. Organic compounds are simply those chemical compounds that contain carbon. Inorganic compounds do not contain carbon.

Water is such an excellent solvent that it can dissolve some organic compounds, which further complicates things. Typically however this is only a small percentage of the organic wastes produced.

Inorganic compounds, ammonia, produced by Koi are completely water soluble. You will never see them. This is often the source of much confusion - if you can't see it how do you know it's there? Or how do you know how much is in the water? And, how do you know when it's all gone?

This is the reason that any good Koi hobbyist will equip themselves with a good quality water test kit that measures important parameters such as these. It is essential to know exactly what is happening in your Koi pond when it comes to these measurements.

Good water quality will have no dissolved waste organic or inorganic compounds. It will also have no waste solid organic compounds. In other words, good quality water will have zero waste. Zip. Nothing. Ever.

An important aspect to this then is that it is not acceptable to have good water quality only half the time. This means that during the other half the water quality is not good!

And what happens when you feed your Koi? You do actually have to feed them you know! Yes, you guessed it. These darling living jewels stuff themselves silly and promptly turn into little swimming ammonia factories, releasing clouds of poisonous ammonia at an alarming rate into the pond. They also produce significant quantities of solid organic waste, some of which dissolves into the water.

This is bad news. Unfortunately it's a fact of life that we as Koi keepers have to deal with and promptly.

And it's now that your once pristine water quality is fouled up completely by the very things that you so enjoy keeping.

In all my years, I have yet to see a potty trained fish.

Excellent water quality in a Koi pond

We haven't even touched on excellent water quality yet! I have only defined good water quality as being completely free from wastes. Excellent water quality is not only free from wastes but it has good dissolved oxygen content. It has good levels of trace elements and it has excellent pH, and pH buffering capability. It is water that is not too 'soft' or too 'hard'. It is water that has a low pathogen count, has a low fungal count. It has a low viral count and a low heterotrophic and disease causing bacterial count.

Exceptional water quality has all this and more. It has the qualities that we haven't even measured yet, that we simply don't know about that Koi will appreciate. All that we do know about these particular as yet un-researched qualities is that they are not necessary for keeping Koi alive. They might play an influence on the Koi's colour or the Koi's comfort levels but that's as much as we know. At least up until now.

You cannot have excellent water quality if you do not have good water quality to begin with. Your pond must be able to swiftly remove all waste from the pond. This fundamentally the most important process in any Koi pond and the one which should take up most of your attention. If you neglect it your Koi will pay a heavy, terrible price and you will not be able to control any of the parameters that are required for excellent water quality.

By now, you should be a little confused. I have deliberately not explained any of the water parameters in much detail but in the next section on our swimming ammonia factories, I will go into some detail on the important processes which should help clarify the issues.