Lee Calladine's video: Purge out your bottom drain

Hi its Lee from the Japanese water gardens, in this video I am going to be explaining how you can avoid a blocked bottom drain on your Koi pond. The bottom drain draws in water and solids off the very bottom of the pond into the filtration system were they can be settled out or mechanically sifted. The water level in the pond is the same as the water level in the filtration system. After the water has passed through the filtration system it is pumped back to the pond. We refer to this as gravity fed filtration. Fitting a bottom drain in your pond is the single biggest step in the right direction you can take when constructing your Koi pond. But if it's not kept clear it can become a major headache. As part of your regular pond maintenance you will need to perform a purge on the pipework. The purpose of the purge is to flush out any sediment that has settled in the pipe and not passed into filtration system. If the purge is not done sooner or later the amount of sediment will increase to such a degree that it will completely block up the pipe and you will have a difficult job getting it clear. To purge your pipe work you will need to switch of power to your pump, UV and any other pond equipment with the possible exception of your air compressor. You will then need to isolate you filter from the pond. Hopefully when your pond was constructed you installed a set of valves for just such an occasion. In our case we have a four ponds connected to our filtration system, each pond has its own valve. We have two separate returns each with an isolation valve. When all the valves are closed we can drain down the water in the filtration system without affecting the pond water level. Opening up the drain on our vortex chamber drops the water out of the bottom and flushes any solids that have accumulated in the vortex to waste. To clean up the sides of the vortex I also have a brush to hand to give the chamber a good scrubbing down whilst waiting for the water to drain away. When the vortex chamber is empty we are ready to perform the purge. Opening bottom drain valves let's the water flush through quickly. With the vortex standing empty and the ponds still full of water there is a significant amount of water pressure it pulls out any debris that has accumulated in the bottom drain pipework. You will see the water starts clear then turns murky for a few seconds as the debri from the pipes is expelled. When the water from the drains is running clear the valves can be shut and the vortex will empty out again and flush away all the sediment. After the dirty water in the vortex has drained away the valve on the bottom can be closed. To restore the pond to normal operation the bottom drain and return valves are opened up. The water level in the filter will rise to match the level in the pond. If a large amount of water has been lost to waste it will be necessary to refill with fresh mains water before the pumps can be turned back on. In our system a ballcock automatically sets the level. When the water level allows the power can be turned back on to the pumps and UVs. The filter and pond is back up and running. The bottom drains are all clear of sediment! I hope you enjoyed this video and will subscribe to the channel. Leave any questions in the comments below. Its bye for now from Lee at the Japanese Water Gardens.