HOB Overflow Flooding solutions

We have all read the flooding stories related to HOB Overflows and I would like to know if anybody has a solution to the problem. The most common story is the power goes off and when it comes back on Overflow loses siphon and you wind up with gallons of water on your carpet. I know there has to be a solution to stop this from happening but I am new to this and want to set up a 75 gallon with HOB and need a solution. There has to be a way of cutting off both the return pump and the overflow box when the power comes back on or stopping the overflow box if the return pump fails so please give me your solutions or ideas.

 

The best solution to keeping the HOB overflows from flooding is to go to a drilled tank.

 

That would be great if I had a predrilled tank but I do not so I need any solutions for a 75 gallon tank that will use a HOB overflow.

 

Buy an Eshopps.

The only time mine ever looses siphon is when I take the U tube out do clean it.


If you buy a CPR or any weir style you had better buy an aqualift pump to go along with it or you'll have problems eventually with siphon loss.

 

I disagree. HOB overflows are normally due to user error.

Drill a 1/8" hole into the return just below the water's surface in your DT. This will stop a reverse siphon from starting. Keep the overflow box tha is in the DT just low enough to skim the surface. This minimizes the amount of water that will enter your sump. The most important thing to do is make sure your sump can hold the excess water. You can check this by turning your return pump off and allowing the return to break siphon and the overflow sucking in the excess water.

A HOB overflow should not lose siphon when the power goes out. As long as it is set up properly, your siphon will not break. They are designed to not lose their siphon. The water wil stay in the u-tube as long as there isn't an excess of air bubbles in the u-tube. All you have to do is start the siphon properly the first time and you are set.

Like I said before, when the HOB overflows are set up properly they do not overflow.

 

Thanks for the info reefmonkey and xmetalfan that will help. On another thread somebody suggested using a check valve, do you use one of those also?

 

I never used on on my 50. I drilled the small hole into the return just below the surface of the water. A check valve will work better by not letting any water enter the sump from the return line, but the watter will still enter through the overflow until the water level is below the teeth. Putting one on the overflow box is pointless as it needs to allow water to enter the sump.

 

The hole that you drill in your return.....make sure you take a paper clip or something and clean it out when you do tank maintenence. Mine will clog up with salt after a few months. YMMV

 

Are you meaning an air check valve? If so no. I don't have any external tubes to pull air out of my U tubes. Don't need them. I run airline up the utube and draw the air out to start a siphon. The siphon is never lost during power outages from either weather or when I shut down for maintenance.
If you decide to drill a hole and aren't using an aqua lift, you should super glue a check valve into the hole otherwise air will be allowed to get back into the system and will break the siphon. If you go with an aqua lift pump on a set up I highly recommend you have a diaphram kit on hand as they are prone to wear out quickly ime.

 

Anyone whose HOB overflow fails after a power outage has a badly designed overflow. They should never lose siphon when designed correctly.

The way it works is that the water level equalizes on both sides (inner and outer) of the U Tube, keeping the siphon from ever breaking.

A check valve does nothing for you. The only thing it may prevent is the return line from overflowing via siphon back into the sump in the case of a power outage, but that would be another problem solved by effective design. Just keep the end of the tube over the top of the inside box of the overflow.