I see, yes that makes sense....


On Sat, 26 Jan 2008 08:10:35 -0500, Wayne Sallee
wrote:

I'm assuming that you are referring to the box that
is in the aquarium.

It's because the water level in the box is lower
than the water level in the aquarium, and when you
lower the box into the water, it has more pressure
to push the bubbles through. By increasing flow
rate, and/or decreasing U tube diameter, you
decrease the chance of bubbles staying in the U
tube. By the way, if you were to experimentally
remove the inside box, you would get more water flow
through the U tube, but as soon as the water in the
tank reached equilibrium, the water flow would be
back to where it was originally.

Wayne Sallee



gaijin wrote on 1/25/2008 9:54 PM:
Thanks for that, I will give that a try. Do youhave any idea why the
bubble dissappears whe the box is removed from the tank?

On Fri, 25 Jan 2008 20:54:03 -0500, Wayne Sallee
wrote:

Oops that should have said 1/2 inch, instead of 1 inch.

Wayne Sallee



Wayne Sallee wrote on 1/25/2008 8:25 PM:
That's why built in overflows are so much better. Remember that next
time you are purchasing a tank. So many stores push the overflow box
because it's easier for them to make a sale, and the customer is none
the wiser. In the mean time, here is a little trick that I found to
help. Cut you a piece of vinal tubing that is narrow enough to easily
slide through the U tube. Cut that piece of vinal tubing 1 inch in length.

Tie a piece of fishing line to it, and stick it into the U tube. Then
with the water flowing through the U tube and down the overflow, adjust
the position of the 1 inch tube to a position that helps keep the
bubbles from becoming a problem.

Wayne Sallee



gaijin wrote on 1/25/2008 8:13 PM:
I have always had a problem with my hang overflow unit. The siphon
always gets an air bubble in it and eventually gets big enough that
the siphon is in danger of breaking and the water level in the tank
gets very high.

While tinkering around today, I noticed that if I remove the overflow
part of the box that sits inside the tank that the air bubble
dissapears and the water flow greatly increases. Anyone have any idea
what this means and does it give any hints as to a possible fix.
Does it mean that the overflow box is too small? I have used over
flows before and I just don't know why this one is giving me this
problem.