Fluid Dynamics Question

jmsalt1

New member
I moved a couple weeks ago and am in the process of setting up my 90 gallon AGA tank that I had on the second floor of my previous home.

Well, the new location of the same 90 gallon AGA will be in my basement and my question stems from the potential location for my new sump and refugium. The basement floor under the original part of the house built in 1919 sits approximately 24" higher than the basement floor in the new part of the basement where the display tank will be located. They dug down deeper to make the new part of the basement more comfortable (higher ceilings). The distance from the floor to the bottom of the tank where the display is located in a custom stand in the new part of the basement is 32". I want to locate the new sump and refugium in the old part of the basement in a work area that has unlimited room for equipment, a floor drain, a slop sink and the like. I can do this by drilling through a wall to gain access to and from that work area.

Given the above, I have an 8" drop from the bottom of the display tank to the floor of the unfinished work area where I want to locate the sump. After the bulkhead and 90 degree elbow exit the bottom of the display and the bulkhead for the sump is installed above the bottom of the sump (probably 2-3" from the bottom of the sump tank) in the work area, let's assume for purposes of this discussion that the point where water enters the sump is rougly level with the point were the water leaving the display exits the factory overflow and makes a 90 degree turn and flows horizontally to the sump. Basically, excluding the unions where water exits the overflow and enters the sump, the run between the two tanks is level. Obviously, water from the display would enter the sump below the water level that would need to be maintained in the sump. I would like to keep the water column in my sump at rougly 8" deep. I should also point out that the factory overflow in the display would be equipped with a standpipe that elevates the point at which water exits from the overflow approximately 12" above the bottom of the display. I usually keep the overflow full of enough water so it is roughly half the height of the display. In the past I used a ball valve to regulate the flow and eliminate the noisy gurgling that would otherwise occur. I would then pump water back up to the display and have it come over the top edge of the tank rather than dropping down below the tank and running it back up the standard hole drilled in the overflow compartment at the factory by AGA. I would block this hole off with a bulk head fitting and cap it off.

Will I be a able to get enough flow from the display (specifically from the factory corner overflow fitted with a standpipe that elevates the point at which water exits the display roughly another 12" off the bottom of the display tank) into the sump as described above to make this set up work? Is it OK that the point of entry from the display at the sump will be 5"-6" below the top of the water column in the sump? My gut is that this will be OK, but I'm a CPA (marine biologist wanabe) not an engineer.

The supply to the refugium (elevated in the work room so the bottom of the fuge would be rougly level with the top of the display tank in the other room) would be T'd off the return from the sump to the display and would gravity feed back to the display. The elevation of the work room (2 feet higher than the floor where the display is located) simplifies an elevated fuge design and will still be very accessible and easy to work on.

Worst case scenario, if the sump can't be located in the work room, I would put it under the stand and only the fuge would end up in the work room.

Any help and comments regarding the location of the sump relative to the display would be greatly appreciated.

Regards,

Jeff
 
Jeff,

A picture with dimensions would help. The water level difference that counts will be that of the TOP of the water line in the refugium to the TOP of the water level in the overlfow. That will be the head height (or drop) of the water.

If you can locate the sump under the tank, that would be great. Put the refugium higher than the tank and pump water from the sump to the refugium. It will then flow back into the tank. (you can also pump from the display to the refuge, but you have to be careful how you set this up, as you don't want to make a mistake and overlfow the sump).

With regards to the expected flow... well that depends on the drop as mentioned above and the type and length of plumbing.


Bean
 
Bean,

A picture with dimensions would help.

I agree, a visual of the expected system layout would be helpful. I will work that up and figure out a good way to post it in the thread. I have not done that on the site before so any tips are appreciated.

The water level difference that counts will be that of the TOP of the water line in the refugium to the TOP of the water level in the overlfow. That will be the head height (or drop) of the water.

The display tank is 25" tall. So 25" - 12" (previously stated height of the water level in the overflow) leaves 13" from the water level in the factory overflow to the top of the display tank. Assume that I position the refugium so the bottom of the fuge is level with the top of the display as previously stated. If I drilled the bulkhead overflow return to the display from the fuge 12" up from the bottom of the fuge tank, this would result in a total head height (or drop) as you described above of roughly 25". The top of the water level in the refugium to the top of the water level in the display's overflow would be roughly 25" based on this initial design idea. I have the ability to increase this drop by 1)raising the height of the stand (I will be building the stand) the fuge will be sitting on in the work (mechanical) room and/or 2)drilling the bulkhead overflow in the fuge up higher than 12". I have not purchased or drilled the sump or fuge for this set up yet.

Should I be targeting a head height drop from the water line in the fuge to the water line in the display overflow greater than 25"?

Initially, I was (and probably still am) more concerned about the water level difference between the water line in the sump and the water line in the display overflow. This is because I can't increase that distance much without having a new display stand constructed or moving the sump to the alternative location under the display tank (limiting the sump and work area around it to the footprint under the stand). I can raise the fuge quite a bit in the work room so fuge height relative to the display didn't concern me as much. Any additional comments are welcomed. I will work on getting a diagram posted as well.

Thanks,

Jeff
 
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