Grandiose plans of pond expansionism

I can do it in a 42L bucket, so why not a 3600L chlorine-bleached communal fountain? It can’t possibly be that difficult riiiighhttt?

The basic idea is to take this sterile environment and convert it into a self-cleaning, biologically balanced wildlife pond, replete with a variety of native plants and minibeasts that will hopefully help encourage other wildlife into our communal garden. A few conversations were had, people seemed to be very keen, and before I knew it the fountain was emptied, scrubbed and refilled.

Prior to adding delicate and somewhat expensive aquatic plants, I wanted to address the chemistry of the water. Given the previous state of the pond, I needed to sort the chlorine content first. Chlorine will evaporate off on its own given time, but modern tap water also carries chloramine, which is chlorine bonded to ammonia, and that bond makes it stable enough that it won’t just diffuse away. It needs a dechlorinating solution to shift it. If any chlorine were left, nothing would thrive, and it would take out the beneficial bacteria I’m relying on to run the nitrogen cycle down the line.

I also wanted to do an insurance test for legionella. Warm, still, stagnant water is the kind of environment it could thrive in, so I sent off a sample to a licensed testing laboratory.

While that was away I ran the water through a MARS Fishcare kit for a baseline of the nutrient load.

	reading
pH	8-9
Ammonia	0 ppm
Nitrite	0 ppm
Phosphate	10 ppm

The Legionnaires’ test came back negative. The chemistry was a mixed bag. Ammonia and nitrite both sat at zero, exactly what you want at this stage: nothing has started decomposing yet, so there’s nothing for the nitrogen cycle to work on. Phosphate, though, was pinned to the top of the chart at 10 ppm, and phosphate is what algae thrives on. The pH was high too, up around 8 to 9 where London tap usually runs 7 to 8. Perhaps this was the concrete fountain leaching a bit of lime? Although there is some sort of liner to it. At this point I was ready for the experiment to go full steam ahead.