Say you want to have a bed that is constant flood, always filled with water. Water comes in through the hose. Water drains out via a standpipe. Very easy to understand.
But if you’ve ever used a simple standpipe, you know it can be crazy loud. I experimented early on with a constant flood hydroponics system. Over time the standpipe started to gurgle noisily. It was terrible.
It was so bad, I was desperate to quiet the standpipe. I came across mention of a "Durso Siphon." Turns out this isn't a siphon at all, it's a modified standpipe that Richard Durso developed to quiet the 1500 gph flowing through the 180g Reef Aquarium in his dining room. Richard describes the reason he was driven to develop his standpipe design at his website:
"The aquarium came with a perforated pipe (a tube with hundreds of holes in it) inside the overflow chamber. This allowed the water to flow into the pipe quickly. However, this also meant that the water level in the overflow chambers was very low — about 3 inches (8 cm) deep.
"With such a low water level, water entering the overflow chamber had about a 20 inch (50 cm) drop! This sounded like Niagara Falls with about 1,500 gallons (5700 liters) per hour enter the overflow chambers. Secondly, each chamber made a gargling noise — sounded like a toilet flushing 24 hours a day. It was so loud my wife could not sleep. I had to fix it fast!
- Little to no water fall.
- Whisper quiet, no splashing or gurgling.
- Each chamber becomes a refugium.
- Chambers will not drain in a power outage.
- Pipe is self priming."
If you want to convert one of your grow beds to simple constant flood or to floating raft, here’s a quick video clip showing how it is done.