HOB overflow box help

ok so im alomost ready to set up my sump. but i worryed about the power going out and having my sump overflow..So is it possible if the power goes out for the overflow box to keep its shipon and over flow the sump tank if so how do you prevent it....i already know how to keep the return line from over flowing the tank so thats not what this question is about...PLEASE ANYONE THAT CAN HELP

 

I have an HOB overflow and there is no way that I know of to keep siphon if the power fails. You just need to make sure that the water level of your sump and tank don't exceed the rim. If my power goes out my tank will pump about a gallon through so I know it won't overflow. It's a balancing act that takes a little time to get right. I hope this helps and sorry in advance if it didn't!

 

My eschopps overflow keeps the syphon if the power fails, when it comes back on the "U" tube just keeps goin as if nothing happened...

 

I have never lost a siphon either. Check out this video from a fellow 3reefer.

YouTube - how to prime a aquarium overflow box

 

I'm a little confused about your post--a little more detailed and clear explanation would help. I’ll give it a shot, but excuse me if I touch on something you have already figured out. I have an Eshopps u-tube overflow and HAVE lost siphon when I had my sump off for a day. I don’t how it lost siphon, but the u-tube was empty when I finally restarted my pump. Maybe the cat stepped on it, who knows..

Prevent the sump from overflowing in a power outage – drill 3-4 small holes in the return line about ½” under the water line. This will limit how much water can be back siphoned through the return pump. Multiple holes are to still allow function if a snail or other object is blocking one or two of em.

Prevent loss of siphon – your overflow box will have two sides: the inner skimmer chamber and the outer drain box. The outer drain box should also have two or more sections within it divided by a small wall. The tip of the u-tube used to flow water from the inner skimmer box to the outer drain box must sit below the top of this small wall of this chamber in the outer drain box, keeping it under water at ALL times. This is what retains the siphon. Sounds like you may have a different style of overflow box though, or a DIY.

Preventing overflowing of display tank – This one scares me the most and you say you have it under control, but are asking about how to maintain siphon..?? If your siphon breaks in the overflow box and your power is turned back on, your return pump will keep pumping water in the tank and none of it will drain—eventually overflowing your tank until the sump’s return chamber is run dry. A great DIY on how to prevent this overflow can be found here http://www.3reef.com/forums/i-made/diy-display-tank-overflow-return-pump-kill-switch-105442.html This safety float has saved my butt three times in the last couple months.. dunno what I would do without it.

 

The overflow boxes similar to the eshopps design have that little wall/chamber(as mentioned above) that should preserve the siphon once the pump is off and back siphoning has finished.

Your tank shouldn't over flow either, because the skimmer box will stop taking in water once the water level drops below the teeth/lip of the skimmer box.

Not to thread jack or anything. but I started up my sump yesterday too and I just CANNOT get the overflow and pump to match water flow. The water level in the sump either drops too fast, too slow, raises too fast, too slow. Basically I just can't get the flows to match. help?

 

I think by "tank" you mean sump. But you're correct, the sump's water level shouldn't rise very much as long as you're using an internal skimmer box AND drilled your relief holes in the return line just below the water line.

What kind of overflow box (type and flow rating) and return pump do you have? Do you have any type of foam pre-filters installed in your outer drain box? Do you have any ball or gate valves installed in your drain or return plumbing? What size plumping do you have? Is it hard or soft line? Any bends, elbows, or any restrictions?

Your overflow box flow rating should be above the return pump. The overflow box will only flow what it's given and should match the return pump AS LONG AS the overflow boxes total flow capacity isn't exceeded. Your actual return flow will change a little with temperature, salinity and other changes, but your overflow box should automatically adjust.

 

Oh yes, I meant sump .

I'm using an Eshopps PF-nano rated for 200GPH on my 20gallon. I'm using it with a Maxijet 1100 pump rated at 300gph. I know its a bit high, but I figured with the height, it should even out. But granted the height from the sump to my tank is maybe only about 40". The only foam I have in my drain box is the foam that goes over the pvc that came with the overflow. I have one ball valve installed on the return. The plumbing I used is just clear vinly softline @ 3/4" for the overflow and return. No restrictions really. The only bends would be two 90 degree bends for the return outlet going over the rim of the tank.

So you think my pump is too strong?

 

Put a ball valve on your in and out line

 

I have a ball valve on the return back to the display tank. What exactly would a ball valve on the overflow to sump do? Not being sarcastic, i really dont know