Water Experiment

My experiment is now into its third week and slightly disappointingly there's still no sign of any algae. Last weeks weather was very dull and grey though, not ideal for growing algae. So far all I've added is a total of 4 koi pellets. They take on average 2 days to sink and so far only the first one has finally broken up. Earlier in the week the water did become a little milky in colour, which could have been a bacterial bloom but things now look much as they did at the start. This weekend I did a few tests to see if anything was going on.

pH
The first pH reading was 7.5 and quite surprisingly it's now 8.4! I was expecting if anything a move the other way towards acid. Thinking my first test was wrong I have re-tested the tapwater and water left to stand, and got the same results as before. To some fish keepers this may seem obvious but something in tapwater probably CO2 or chlorine, effects the pH. I have heard that carbon water purifiers can lower the pH in much the same way. This means that the pH hasn't changed because of anything in the experiment, but due to it being left to stand.

Ammonia & Nitrite
I have successfully created water that would be deadly to most life, let alone koi. This is a boast I don't want to make too often, but it's good to see a result. Ammonia levels are close to 1 mg/l which at a pH of 8.4 would quickly prove fatal. Equally deadly the nitrite readings are off the scale at over 2 mg/l. The fact they are both present confirms that the koi pellets are being broken down and some nitrification is going on, but it may take a few more weeks to achieve an equilibrium. Although the total ammonia concentrations are much higher in industrial waste water treatments, higher levels can even inhibit the bacteria that feed on it. With nitrite approximately double the ammonia, the next step is establishing enough nitrite oxidising bacteria. I would hazard a guess that the ammonia levels, if not coming down are being controlled.

Nitrate
Nitrate is up to 50 mg/l double what the start level was. I'm not totally sure how this has happened, but I suppose some oxidation of nitrite must have occurred. This is not an unreasonable level to have in a koi pond, and with limited ways for nitrate to escape most people rely on water changes to keep it down. With nitrates in my tapwater measuring 25 mg/l, it's fairly obvious that quite large amounts are needed to control the rise.

Nitrate is often blamed for causing algae but like other plants it is just one of several requirements needed. Algae has even been known to survive in distilled water when all the other components are strong. The levels in my tapwater are more than enough so I will give it a bit more time before looking for clues.

Conclusions so far
I've been really surprised how quickly it has taken for the water to become toxic. Admittedly it's only 10 litres and there's a very small surface area, but this is bigger than some goldfish bowls and the filter pump turns the water over quickly. This just goes to show how polluting koi food is and how even if the water looks clear it may not be suitable for koi to live in. One reason for the rapid bacterial activity could be due to the probiotics in Saki-Hikari, but I have no way of telling. Visually there is no discernible difference between the two brands of koi food that I have used. This is something I may test in another experiment.

Having only added 4 pellets of food I was worried that without any koi present, part of the cycle was missing and ammonia would be in short supply. There is a technique that some koi and tropical fish keepers use when starting up a new pond or aquarium called a 'fishless cycle'. This is useful because the fish are spared the extremes of ammonia and nitrite as the filter establishes itself. Without the fish an ammonia source has to be added, in my case with the koi pellets, but for those whom don't wish to waste expensive koi food a cheaper and more controllable option is to add ammonium chloride or ammonium hydroxide. These are often found in household cleaners but don't use any with scents or surfactants, only 100% ammonia.

With plenty of nutrients in the water I think I can cut feeding, and possibly change a small amount of water, if ammonia levels don't come down. There are modifications I can make to the set up and I have plans to do other tests, but for now I will keep things simple and see what happens.

Getting Started

My water quality experiment has been running for a week now but there's very little visible change. This is not surprising considering it was started as a sterile environment with raw tap water and the only things added have been dechlorinator and three Saki Hikari pellets. This is what many koi keepers go through when filling their ponds for the first time and is often referred to as getting the pond to cycle. This means establishing a colony of bacteria in the filter which break down the waste products that build up into safer compounds, ammonia being the most harmful to koi. The cycle part refers to the nitrogen cycle, of which ammonia as a compound of nitrogen is part of.

A koi pond filter can take anywhere between a week to over a month to fully cycle depending on the conditions. Around 20 days is about average to establish a working bio filter but it may take many more months before it's at full strength and mature. This is why new ponds can experience problems often called new pond syndrome when too many koi are added too early. Nearly any body of water will not remain sterile for long and even chlorinated tap water will not kill all organisms, the reason you shouldn't clean contact lenses in it, but there are ways to speed things up.

The quickest way to seed a bio filter is to introduce some media from an already established filter. For most people this isn't an option and it could be a source of introducing disease so the next best thing is to buy a product that contains a ready culture of bacteria. These can be great to get things going or as a boost but they don't contain the true nitrifying bacteria needed for an efficient and stable koi pond filter. The nitrifying bacteria Nitrosomonas and Nitrobacter (Nitrospira is in fact more common as the nitrite reducing bacteria in water) are much slower developing and being autotrophic need a steady supply of the chemicals ammonia and nitrite to feed on, so are very difficult to store alive. Until these bacteria gain in numbers it's best to carry out regular water changes and only introduce a few koi with light feeding to start with.

In my experiment I've not added any bacterial products as I wanted to let things develop naturally and not be influenced by an abundance of certain strains. Most of these products contain heterotrophic bacteria which can feed on a variety of things and are responsible for mineralising organic waste into ammonia. They can do some of the work for the nitrifying bacteria but given a choice they prefer organic waste because it releases more energy.

Without any koi the only source of ammonia so far will be from the food pellets but these first have to be mineralised by hetertrophic bacteria. Having tested the water the ammonia levels are registering at around 0.15 mg/l which in a pond of koi would not be healthy but it does suggests that bacteria are present. One of the sources of the bacteria could have been in the koi food itself as Saki Hikari contains a probiotic to aid digestion. I'm going to switch foods to see if this makes any difference but it maybe something worth investigating later on.

Autumn pond maintenance

Listening to the news today it's been reported that the UK has had the longest period of warm weather on record. I doubt this is all to do with global warming and sooner or later things will get back to normal. Now then, if you haven't done so already, is the time to get your koi pond ready for when the cold does eventually arrive.

The koi are definitely benefiting from the warmer weather as they continue to feed, but this should be reduced and only once or twice a day. Feeding koi a wheatgerm based food helps their digestion and the lower protein reduces any waste that the filter has to cope with. As the temperatures drop and your koi become less active so do the bacteria we rely on so heavily to keep the pond healthy. Luckily for our koi the growth of bad bacteria is also slowed but to help prevent any problems we should remove the sources of pollution before they can get a chance.

One of the biggest headaches this time of the year are leaves falling in the pond. They seem to be hanging on to some of the trees later this year, as though they like us are not quite ready for this weather to end. The most effective way to keep leaves out is to cover your pond with a weather proof cover or net. These both provide benefits but to some they can prove unsightly and not practical with every shape and design of pond.

The option then is to regularly remove them yourself or with a skimmer. Most leaves floating on the surface won't cause many problems and can even look rather nice, something the Japanese take great delight in, but if left to build up they can block pumps and later decompose effecting water quality. One variety of koi the Ochiba Shigure is even named after its appearance resembling dead leaves on a pond.

If you don't prevent the leaves from entering your pond then make sure the skimmer is regularly emptied or alternatively remove them yourself with a net everyday. This can be a pain but if removed now come spring you will have less problems to deal with. The greatest risks are leaves settling at the bottom or in quiet areas and then turning stagnant. A pond vacuum is very useful for this as well as cleaning out any other areas of the pond that collects dirt. There are a number of bacterial products that claim to remove waste and mulm from a pond before winter, but what needs to be remembered is that they will be less effective the colder it gets and should never be a substitute for good old fashioned cleaning.

Koi Water Treatment Experiment

Back in August I wrote about a new water treatment for koi ponds called Aqualibrium, which while I believed it could be effective in removing algae I was also sceptical about some of its other claims. Well the nice people from Aqualibrium contacted me and along with some more information sent me a bottle to try. I must say going on the first impressions, the aluminum bottle looks good but what I and many other koi keepers really want to know is does it work?

Now never one to turn down a free gift I was interested to give it a go, but the primary reason someone would buy this product in my opinion would be to get rid of algae and blanket weed, neither of which is a problem for my pond. This time of the year is not really ideal for trying a koi pond treatment as the temperatures are going down and with daylight hours getting shorter most algae will tend to die back by itself anyway. Having tested all the parameters of my pond water I realised that any improvements in quality would be difficult to detect without expensive and very sensitive equipment. The problem then is how do you test an algae treatment when you haven't got any algae? To be fair to Aqualibrium and in the hope of getting some dramatic results I've decided upon setting up an indoor test rig that will be more controllable.

Using a large vase of water I hope to recreate in miniature the conditions found in some koi ponds, starting by growing algae which shouldn't be too hard. With most of the organisms present except for the koi it will be possible to pollute the water beyond a point that would normally be tolerated. Before I start this experiment I have to say that I'm not a scientist and there may be a few flaws in my plans so even if the results are conclusive this shouldn't be taken as definitive proof. Really this is just a bit of fun and although I have a few theories I'm not totally sure what's going to happen.

Starting from scratch with fresh tap water and new filter media I shall go through the process of establishing a bio-filter which often causes problems for many beginners when setting up a koi pond for the first time. As Aqualibrium works by activating the microbes already present in a pond we need to first establish a healthy culture of the right bacteria. One of the main reasons that a pond turns green is because of the build up of nitrate levels produced from the nitrifying bacteria. By including a small filter in the vase that supplies an abundance of nitrates and given plenty of day light, algae should easily grow. I'll try to explain the processes involved in more detail later on.



I'm using a small aquarium filter that I replaced the foam with Fluval Biomax - a highly porous ceramic media, because this media provides a very large surface area for bacteria to grow on while it shouldn't trap the algae as it develops. By regularly feeding the system with koi pellets and testing the water I should be able to monitor any changes. Starting with chalky London tap water with a pH of 7.5 there are as one would suspect few impurities worth testing for but it's worth mentioning that nitrate levels are between 25-50 mg/l. This is perfectly fine for koi but it does show that when doing water changes you may not be reducing the nitrate concentration in your pond as much as you think. In fact in some ponds the addition of more nutrients in fresh tap water can be the cause of algal blooms.


To avoid this possibly becoming like watching paint dry I will update when anything significant happens. As well as a test of Aqualibrium this will also be a good opportunity to explain and try out certain theories of how a koi pond filter works and how you can improve yours.