Overflow box not siphoning

[Johnny Reefer]

Originally Posted by TheReefGeek

Johnny, can you explain why your overflow almost flooded?

It didn't almost flood. I said I could see one comin'...meaning if I kept with the siphon overflows I envisioned a flood in the future.
Started with two overflow boxes, one U-tube in each. Did a test to see what would happen if one U-tube lost siphon. Test failed. The one siphon left couldn't keep up with the return. So, I doubled up the U-tubes. Two in each box. But then there was too much distribution and one U-tube would lose siphon over a long period of time, leaving only three doing the job. One day I noticed salt creep on the plumbing to the sump. So I shut the pumping down to silicone the plumbing joints. My sump slooooooowly continued to fill with water. Turned out water was being siphoned out into the sump through the powerhead's airline tubings. Oh ya? So how do I stop this? Check valves in the airline tubing. So I went out and bought a bunch of check valves. But I never installed them. I decided @*^%$# this. Shut the sump down, went back to a canister filter and pressed on as before until I could afford a drilled tank.
I should qualify this by saying that part of my decision was the fact that I worked away from home for long periods around that time. But still, wether one is working 500 miles away or 5 blocks away, a flood is a flood. You just find out about it sooner if you are 5 blocks away. JMHO.

Cheers,

[wetcoast]

So after my boss sent me home early today to take care of the mess I was about to deal with - I came in and noticed why my fish were gasping for air this morning, I only had one powerhead going all night due to my mucking around to see if the powerheads were broken (to answer the above question). The airstone and extra powerheads I threw in before going to work helped alot, all livestock was alive.

I decided to give it a whirl again today and everything worked as planned without issues! I just don't understand what the heck is going on here. Mind you - I don't trust it. Looking for a 65gallon tank to drill and then will sell this one.

The saga continues.

[TheReefGeek]

If a u-tube loses siphon, it just means that your pump in your return section of the sump will continue pumping water into your display.

This is not good, but not that bad either, as long as you have measured the additional capacity of your tank, and not built your return section larger than that.

In this case, all that will happen is your pump will run dry, but no flood. 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.

[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.