Microbubbles
Microbubbles
Hi: I have been following your thread, while I too am setting-up a custom 225 gallon tank by AFY in NJ. I specified 1.5" drains in each of my overflow boxes. I went from a sequence barracuda to a pan world 100 to a small Gen-x (1100gph) return pump and still had bubbles. I read with detail over Melev's helpful site and now actually agree with a lower flow through the sump. My (2) tunze 6200 provide enough internal flow. Anyway, I created bubble traps just like Melev describes and still had microbubbles. I changed my plumbing, including my OM 1" flexible return nozzles, since air might be coming in via the joint spaces and still had microbbubbles. I created a double layered drip tray and still had microbubbles. I used felt socks and still had microbubbles. I was about to give up when I consulted with my friend Al Dispigna, the president of the Brooklyn Aquarium Society (the oldest, almost 100 years old, and largest aquarium society in the USA) and he immediately diagnosed the problem. My 1.5" drain pipes were simply too big. There was so much turbulence as the water flowed down the pipes that microbubbles where inevitable.
Solution: I placed reducers from 1.5" to 1" on the ends of each drain pipe and placed each in a felt bag and the microbubbles were all gone. By restricting the terminal lumen of the drain pipes upon exit, the water volume in each drain pipe was forced to back-up and increase. In fact, try placing your fingers at the end of the output of a 1" and a 1.5" and you will see and feel a more solid stream of water in the 1" drain. As simple as this sounds, the water flow is less turbulent and contains less air.
I hope this simple approach helps.
Respectfully, Dr. A
