The OKC club owns the towers that do the initial filtration. They are filled with catalytic carbon, which lasts a very long time. From there, the water travels into a Dosatron, which proportionally injects Amquel or Clor-am-x, at a rate (1:1500) sufficient to remove the latent ammonia in the city water as well as overdosing slightly for the ammonia from the koi in the tanks. We mix about 24 gallons Amquel for each system (using dry Amquel). Usually, we run 4 identical systems.
Each system supplies 10 gallons per minute and feeds about 10 show tanks. This gives a good enough supply of constant fresh water exchange in each tank to keep the koi happy.The waste water exits the drain of each tank through a standpipe and goes to the sewer. Make sure your sewer lines can handle 40 gallons per minute of waste water - very important
That about covers the water system. Obviously, city water parameters will be different and require a different appropriate Amquel mixture.
Phew...
Michael