Neptune Aquatics

Internal Overflow: Flood Prevention

Hi All,
As I set up my new 75g reef tank with internal overflow and integrated return system, what steps (if any) do I need to or should I take to ensure that future flooding is prevented?
Thanks for any tips/advice.
Dennis
 
I have my return pump lifted off the sump floor. If the overflow clogs (or in my case looses the siphon) it will suck air before flooding the tank.

-Gregory
 
Depends upon where you mean for flooding.

If you mean flooding from the display tank out to the floor, then simply have an emergency drain line, one that is NEVER used (underwater) and if your main drain gets clogged water will rise and the emergency will take over (and hopefully you notice the clog before the emergency clogs up :D). Also having screens near (but not on) pipes will help keep critters out (snails are notorious), you don't want the screen actually on the pipe though because that's a sure fire way to make sure it clogs up.

If you mean in the case of a power outage. #1 thing you can do is to make sure your sump is properly sized. I often (and I've been guilty of this) the chamber that pumps water back into the tank is extremely small compared to the rest of the sump. So when you lose power you'll fill that one, up, and the other chambers are already full, and sploosh all over the floor. Also you can help yourself by making sure your baffles are not terribly high, leave some room. Test it all by yanking the power cord on your return pump and see if you'll flood (better to see it when you're actually home!).

Siphon breaks can work too, however make sure you drill them large enough compared with your pipe size, a pin hole siphon break... will not break a siphon. It needs to be able to suck in enough air such that the siphon breaks, and I often have seen them too small. Or they're clogged up (especially light can shine on the pipe). I find it easier to simply have my return pipe just below the water's surface, not so high that you cause bubbles to form, but high enough that pipe itself is a siphon break :D

Bottom line, multiple redunancies help a lot more than a single one. Having a siphon break/high pipe PLUS enough room in the sump incase either fails.
 
Hi All,

Thanks for the great advice. In doing Google searches, I learned about the siphon break. I am confused though. Can someone please spell out for me in "newbie" language where exactly to drill these hole(s)? I think the intention is to drill in the return pipe just above or at water line in the display. However, my return comes up through my overflow chamber. Maybe when I fill the tank up for the first time, this will make sense. As it stands, my water in the display will need to be quite high for the overflow to function. I have the return adjusted so that the flow would be underwater (if my tank were filled). By the way, I am reading drilling two siphon breaks is better in case one gets clogged at the wrong time. Thoughts?

My display tank is 75g (36x24x20). My sump is 30x14x16. The first chamber is where the flow enters from the display in to a sock filter. My skimmer is in this first chamber too. The baffle is high enough to keep the skimmer motor submerged. The center Refugium chamber is pretty big - the biggest of the three chambers. Does this seem adequate?

Raising my pump up is a challenge because the baffle from fuge to pump chamber is not super high and my pump needs to be fully submerged. The pump is somewhat elevated being on a mount with suction cups that add probably a half inch to an inch of distance from the chamber floor.

And as long as I'm on here...I'll add a question (thanks for reading):
I have two powerheads and I want to situate them ideally. I am thinking with my return flow just situated at or slightly below the surface, I would place one powerhead on the right of the centered overflow chamber attached to the back of the tank and aimed across and down and then place the other on the left of the overflow and aimed across and down. Both would be in the middle - upper portion of the back of the tank. Would this seem to be logical placement - good placement?

Thanks again, All, for the insights and support.

Dennis
 
tuberider said:
Drill a siphon break and keep it free from debris.

Yep..these really work and are needed. I just upgraded my setup and forgot to drill the holes. The next day our power went out (what god did I piss off? We rarely loose power) and I lost approx 10 gallons that back flowed into my sump and onto the floor while I was at work.

(I didn't post it 'case I was too embarrassed :8) )

-Gregory
 
Here you go! I have changed a few things...replaced the pump in the return chamber to an Eheim 3000. I have also completed some plumbing since I took these early photos. I will be taking more photos soon and I'm also pondering starting a video blog of my progress.

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I'd also recommend a clear check-valve attached to your return pump. That way, you won't have a siphon through your return line if you lose power or if the pump seizes. The clear ones are more expensive, but you can see if there is a problem developing.
 
99sf said:
I'd also recommend a clear check-valve attached to your return pump. That way, you won't have a siphon through your return line if you lose power or if the pump seizes. The clear ones are more expensive, but you can see if there is a problem developing.

I'm not disagreeing with the need for such a beast. I'm just saying to be careful.....when I was researching these I was told by multiple people that even the clear ones ½” and over are very unreliable and should only be a fall back measure and not be considered a primary safety feature. Mine failed (only 24 hours old) and my sump flooded. It was not clear though.

-Gregory
 
This is what I do. I have flooded the floor but that was mostly leaking CA reactor.

1) My sump has enough capacity so that if it siphons, I can handle several gallons
2) My Oceanic overflow has two holes drilled in it for standpipes. One standpipe is the actual overflow, the other standpipe is SUPPOSED to be the return. Instead I took the return pipe and cut it to a level just above the overflow pipe. If the overflow pipe clogs, the water level will rise a bit and then flow down the emergency pipe. I did not put any "stockman or durso" attachment to the emergency pipe so that it would make a loud sucking noise, thus alerting me to trouble.
3) My return pump also sucks air and blows bubbles all over the tank if the sump return compartment gets low, indicating possible a leak in the main tank or sump. This is also hideously loud and alerts me to trouble.
4) My return pipes hang off the sides of the top of the tank glass using PVC pipe like an upside down J or U shape (hooks onto the top), I drilled a hole JUST around the water level on the water-side of the J. So the idea is that when the return pump is working, water returns normall, though a bit of it comes out the siphon break hole. If the return pump stops, the siphon break hole will allow air into the lines and stop any siphoning of the main tank...you MUST KEEP THIS HOLE CLEAN! Make it large enough to not easily clog! Algae loves these holes! If you don't like it shooting water, you can actually add an air hose to it and direct the airhose somewhere (like into your overflow compartment).

Some people put a flood alarm on the floor near the tank, I should probably do this!

V
 
GDawson said:
99sf said:
I'd also recommend a clear check-valve attached to your return pump. That way, you won't have a siphon through your return line if you lose power or if the pump seizes. The clear ones are more expensive, but you can see if there is a problem developing.

I'm not disagreeing with the need for such a beast. I'm just saying to be careful.....when I was researching these I was told by multiple people that even the clear ones ½” and over are very unreliable and should only be a fall back measure and not be considered a primary safety feature. Mine failed (only 24 hours old) and my sump flooded. It was not clear though.

-Gregory

Good point... don't rely solely on the check-valve. I've had great luck with the clear ones (no failures in a bit over 3 years), but it sounds like Greg isn't the only one to have a problem with a failure.
 
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