A question of sump + power outage (backflow)

[Anonymous]

the n00bie guide has this line:

In regards to a sump, you must consider the fact that when the power goes out on your tank, water will back siphon into the sump, down to the level of the return opening. In order to prevent much backflow, holes need to be drilled at or just slightly below water line on the return end. But, the sump must have enough residual volume to accept the backflow of water without spilling over. That means that the sump should be run less than full during normal operation.


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Question: Holes need to be drilled in WHAT on the return end to prevent backflow? Can someone essplain this to me pretty please? The power goes out in my neighborhood about once a month and I have to make sure that when it happens: 1. the tank doesn't keep siphoning and 2. when the power comes on it's going to not pump water all over my floor

Here's what I'm considering so far: an Oceanic 54g Corner dealio with the Sump/Fuge Combo from Coral Reef below in the cabinet.

... though this is horribly expensive for a buncha acrylic! I used to have a job forming this stuff. I could make this thing in about 10 minutes in the shop! What a rip this hobby is. Heh.

Well thanks for the help.
-me

 

[Anonymous]

Hole on the return path anywhere above the waterline, preferably somewhere within the tank so that when power is on, water coming from the hole does not goes where you don't wanted. Basically, the hole is there to break the siphon by letting air coming into the return pathway.

 

[Anonymous]

Above the waterline in the sump, right? Not above the waterline in the aquarium, correct?

Just a little hole?

 

[hdtran]

Above the waterline in the aquarium.

Look at your return line (from sump pump to main tank). If you run that return line to a spraybar underwater (like many folks do), what would happen if the power were to go off? You'd siphon water from the main tank, through the return line, into the sump.

So, you drill a hole (actually, several holes, to prevent a snail sitting on top of your hole, when the power goes out, to, umm, suck?) in your return line in the tank, just at the tank waterline.

You rely on the fact that water from tank to sump goes thru an overflow, so when power goes out, the water overflows until the level goes down sufficiently that it no longer overflows.

You need to also do a "dry run" (if I may use the phrase). Once you're set up, just unplug the power, and see how much water drains into your sump. Then, plug up the overflow (e.g. simulate snail-in-overflow), and see how much your sump pump pumps back into your tank.

 

[Anonymous]

Cool, thanks. I don't have any of this set up, nor have I ever, so it's a little tough to visualize all of it.

 

[hdtran]

Try sketching something...

Is your tank reef-ready (e.g. drilled in the back or bottom & overflow boxes glued on the inside), or are you going overflow siphon boxes?

 

[Anonymous]

The tank I am going to purchase isn't reef ready, but the local shop says they can convert it for $70.00 ($40 for parts and $30 for labor).

 

[Anonymous]

Of course, if your return line don't extend deep in the aquarium you don't need to drill any holes. Mine just extend about an inch into the aquarium, so when the power goes out the aquarium just drains down an inch. As long as the sump has plenty of room to hold it, not a problem.