Air in Tank

[kellane1]

Hi all,
I am the Ranger at a stocked impoundment in Cairns, Australia and am currently in the process of setting up a display tank for our visitors, the tank is 6' x 2' x 2.5'. I am running a Aquasonic pump as a return to the tank,and it pumps 62 L/M.
The sump is gravity fed by a "hang off the back weir".
Which leads me to the issue that I am having and the hope that you guys can help me resolve it.
The tank has now been cycling for three days and it is a milky colour due to a massive amount of air in the water, I think that this is due to the fact that the weir is creating a vortex and sucking a lot of air into the sump and then the impellor in the pump is fractuating the air bubbles and making them minute and dispersing them throughout the tank.
Is there an easy fix for this?
Thanking you all in advance and I look forward to your replies.

 

[Fishyfanatic]

I am moving this post from the Site Help forum. I'm not exactly sure if this is a saltwater or freshwater tank so I'm just moving it to Saltwater since it deals with sumps .

 

[melosu58]

It needs to be in the general Hardware and equipment discussion. I`m moving it there. What is your overflow rated at? It could be that your pump is pulling out the water faster than your overflow and it`s sucking up air. Just a guess.

 

[kellane1]

Hi,
Unsure what you are referring to by overflow, if you mean the sump, the dimensions are aprox 600mm x 400mm x 410mm, the sump is baffled and there is plenty of water in the last baffle from which the pump returns water back to the tank.
If you are talking about the weir, it is a home made effort by a friend of mine, I guess you could say that it is shaped like a W, but I have noticed that where the outlet pipe from the weir runs into the sump, there is only about 50mm of water at any one time for it to take from. I think that this is because of the level that the weir sits in the water, because of this small amount of water and the 2" outlet i think that this is why it is vortexing and pulling air as well.
Hoped this clarified

 

[melosu58]

Yes I was talking about the weir. We call it an overflow here. Maybe you can lower it in the tank to get more water in it. How about where the return pump is. Is the water covering the pump completly up.

 

[kellane1]

Unfortunately I cannot lower it into the tank any more than it is, And from what I can gather if it was possible to do this then it would just pull more water through it and lower the tank level until it was at the same height, the return pump is not a submersible, it is an external pump, I have just put a 20mm holesaw through the sump with a skin fitting and it pulls directly from that.

 

[cmor1701d]

Is the pump inlet in the sump completely under water?
Is there a vortex in the pump intake area that is sucking air from the surface down into the pump?
An overflow (weir) has gallons/litters per hour rating. The return pump needs to be matched to that rating so that you have equilibrium. You do not want the return pump driving more water back than the weir can deliver to the sump.

Assuming they are matched, how far apart are the baffles in the sump. Can you post a diagram of the sump layout? The baffles should eliminate the bubbles from getting to the return section of the sump.