Overflow box not siphoning

[Johnny Reefer]

Originally Posted by TheReefGeek

To solve this, use a float switch set to turn the pump off if the water level drops too low. Add a second as back-up, and there should be no way to flood.

I just think that the more gizmos and gadgets one has, the more things they have that could malfunction and go wrong. The external system I had, I decided, was getting too complicated with to many "parts" and thus an increased potential for one of those parts to malfunction. The simpler, the better. IMHO.

For the cost of the external box(es), the powerheads, the check valves, the switch, etc. ...why not just pay a little extra and get a drilled tank and buy some peace of mind at the same time?

BTW...I disagree with there being such a thing as a flood proof external siphon overflow system. Sorry.

Cheers,

[TheReefGeek]

Sure it can, just make the drain section of your sump small enough that your tank can take the extra water without overflowing. This would be flood-proof in my mind. (yes, anything CAN happen, your baffles could fall over at the same time or the overflow could leak, which is as likely as your tank coming unsiliconed, so it is no more likely to flood than a tank just sitting there with water in it)

You are correct though, drilling is better, I reccomend drilling all tanks when possible. But if you have an external overflow box and are currently using it, might as well make it as safe to use as possible.

[Johnny Reefer]

Originally Posted by TheReefGeek

Sure it can, just make the drain section of your sump small enough that your tank can take the extra water without overflowing. This would be flood-proof in my mind. ....

Well sure...in theory. But I think for most of our systems that is impractical and undesirable. My sump is a 33 and I figure it's got net 25g in it. I want to put a skimmer in it eventually. If it were any smaller this would be impossible. Also...with 25g of water in there would mean that I would have to have the 180 main tank water level about 4" from the top of the tank. Somewhat aesthetically unappealing. The overflow box(es) would have to be lowered that much further down into the tank, as well, in order for the water to flow into the box(es).

Cheers,

[TheReefGeek]

You dont understand. It is not the whole sump volume, just the return section..... You could have a 100g sump, but a 5g return section.

[Johnny Reefer]

Originally Posted by TheReefGeek

You dont understand. It is not the whole sump volume, just the return section..... You could have a 100g sump, but a 5g return section.

Oh yes, I see. I didn't read the "drain section" part of your sentence.
Glad you agree with the drilled tank being better idea.

Cheers,

[TheReefGeek]

Yep, just for people who already run external overflows, there are some precautions that can and should be taken to minimize the risk: (some of these may apply to CPR style overflow, but I have no personal experience with them)

1. High flow through a u-tube to discourage air bubbles from accumulating in the top of the tube. Do not rely on a pump that can fail.
2. Ensure both ends of the u-tube are submerged even when the power goes out, so that siphon is maintained and flow will resume when power does
3. Observe daily, and clean as needed especially if algae forms in u-tube
4. Tank should be able to "absorb" return section of sump
5. Float switches to prevent pump run-dry is advised for all sump setups.
6. Float switch to cut return pump off when display level rises too high would be good as well.



I own my own diamond bits to drill with too.