Carlson Type Surge Device
This is a DIY carlson surge device I put together. The box is about 12 x 4 x 12, and hangs on the wall above the aquarium. The siphon tube is built using 1 1/4" PVC pipe and elbows. The elbows are cut down to keep the tubes closer together and create a better "U". Water is fed into the unit from my sump with a quiet one pump. It enters the surge device through the black fitting near the top of the box. I had to change this to a 1/2" PVC pipe extended to the bottom of the box to quiet it down. The elbow pointing up is for a safety over flow. The device works by creating a siphon. The box fills with water until it covers the top of the "U" tube. Once the water covers the "U" a siphon starts and empties the box. The black fitting on top of the "U" tube is a siphon break, once the water empties below this tube it draws air and breaks the siphon. The box then starts to fill again and the whole process starts over. This empties about every 60 seconds with the quiet one pump.
I also built the out put using 1 1/4" PVC pipe. I mounted to the wall next to the aquarium and is connected to the surge device with "bilge" hose. Back pressure is an issue with the device. I have read on other web sites that the vent on the out put must be submerged for the unit to function correctly. I have found the opposite to be true. I had to drill a hole just above the water surface so the air can escape the drain line as the unit fills.
The surge does work, but I feel there are serious draw backs. One is the noise. Its very loud. The noise comes from both the siphon sucking in air as it breaks, and then from the aquarium overflow as it tries to keep up with the two gallons of water pouring in. It also produces a lot of air. I do believe this is from the air in the line, and it is pushed out until a full siphon is created. Air in the aquarium and noise are not a welcome thing to most reefers. I could live with the noise if the air issue could be taken care of, but right now I really do not feel the amount of surge provided is worth the drawbacks that come along with the design of the unit. It does empty and fill without fail. I have the pump plugged into the timer for my actinic lights so the unit shut off at night. I am going to build a different out put to try to allow the air to escape before it enters the aquarium, and allow the water to "pour" in, more like a dump bucket before I remove the unit and try something else.
