HOB overflows

[Aimulator64]

Hello again! I’m going to be considering a sump for my undrilled 30 gallon tank. I currently have an aqua clear 50 but would really like to have a media reactor for phosphates and a protein skimmer as well. Someday lol. What I want to know is:

Since it’s obviously beyond dangerous to drill a filled tank even untempered, what is the best Syphon-operated overflow box? I am looking for opinions based on what keeps the most consistent flow rates, what stays in place the best, what’s the most restart-friendly, etc. and for those who have used that kind of box, what do you use for a return setup from the pump? Most through the glass boxes have plumbing for the return. Thanks again!

 

[KyOsIBa515]

CPR makes one that is pretty solid. Incase of an outage it has an air pump to help resiphon. However, if at all possible I would relocate whatever you can. Drain the tank and drill it. Even though HOB’s work still a lot of what if’s. Hate to see you with a mess on your floor.

I was faced with the same problem. To drill or not to drill? Since drilling is pretty hard to find someone to do it for you because there is no guarantee it becomes 100% diy. Being I am running just a fish only for now I opted out of drilling it. If I ever do a full blown reef again I will drain it and drill it. Best of luck!

 

[Aimulator64]

I think a HOB can work fine and is probably less likely to leak than a through the glass, and based on physics the box itself can’t overflow on the back if the siphon breaks. Only problem would be the return pump flooding the tank if the siphon breaks, so I would have to keep a smaller pump reservoir in the sump to prevent that. It seems like dialing in would take some fine tuning. Normal overflows just work no matter what unless you return more than it can actually handle lol

 

[sde1500]

Eshopps or lifereef. Both will start after an outage without need to use a supplemental pump. I’d avoid any that need a pump. 3 years running on my eshopps overflow and it not once has had an issue.

 

[Galaxy reefer]

I've had cpr overflow boxes and never had any issues. If you do go with cpr or a model with a pump to help restart the flow keep in mind you will need to clean the pump every so often. I usually run mine in a vinegar solution to make sure no build up is occurring inside the pump every few months.
Second when you plan your sump height in the last chamber, make sure you run a flood test both ways. The return pump failing and the overflow box failing. I've got mine so if either one or both fail the display tank or the sump will never overflow.
It took some time but it's well worth it. Hope this helps.
Bob

 

[KyOsIBa515]

I think a HOB can work fine and is probably less likely to leak than a through the glass, and based on physics the box itself can’t overflow on the back if the siphon breaks. Only problem would be the return pump flooding the tank if the siphon breaks, so I would have to keep a smaller pump reservoir in the sump to prevent that. It seems like dialing in would take some fine tuning. Normal overflows just work no matter what unless you return more than it can actually handle lol

Even normal overflows can fail. When I had my 75 like an idiot ran the return nozzles too low in the water and had a check valve fail and had a mess. Opps my bad. My wife loved that one.

 

[jrill]

To prevent overflows I use a Aqua Auto AutoAqua Smart Level Security. That way if the siphon breaks it turns off the pump and sounds an alarm. Flood averted.

 

[Montiman]

Another option to stop the return pump from flooding the display in case of a failure would be using one of the reef octopus VarioS pumps with the float valve protection.

 

[Hermie]

my recommendations,
get an overpowered return pump (500+ gph) of a quality brand (personally I have eheim)
for the overflow either eshopps or lifereef simply because less parts to break
if bubbles are accumulating in your siphon tube, either get a smaller tube or increase your return pump's flow (which is why you should get an overpowered one in the first place and dial it back)

 

[Aimulator64]

Tanks for all the suggestions everyone! I’ll probably get the eshopps overflow and put a ball valve on the return pump.

 

[Retro Reefer]

Tanks for all the suggestions everyone! I’ll probably get the eshopps overflow and put a ball valve on the return pump.

Good choice, IMO for the price eshopps are hard to beat.

 

[vlangel]

I have always used overflow boxes (since 2004) and eshopps is my favorite. I like the variable flow DC pumps because you can match the flow to precisely the drain capacity. You want the flow fast enough that no bubbles build up in the U tube but not so fast that a siphon is started at the standpipe and you get the flushing noise. When the flow is precisely match to the drain capacity, the siphon will always start without fail.
I do not like using an aqualifter pump to make sure a siphon restarts because once when a power surge went through our house the aqualifter was fried by it and the siphon did not restart. Fortunately I was home.

 

[jd371]

Eshopps or lifereef. Both will start after an outage without need to use a supplemental pump. I’d avoid any that need a pump. 3 years running on my eshopps overflow and it not once has had an issue.

Same here, going on 4 years without any issues. HOB's are finicky to set up correctly but once done you shouldn't have any problems. The only drawback with HOB's is the overflow and U-tube need to be removed a few times a year for cleaning, and out of the box they are noisy but can be corrected with a diy Stockman Standpipe (plenty videos on Youtube on how to make one).

I have always used overflow boxes (since 2004) and eshopps is my favorite. I like the variable flow DC pumps because you can match the flow to precisely the drain capacity. You want the flow fast enough that no bubbles build up in the U tube but not so fast that a siphon is started at the standpipe and you get the flushing noise. When the flow is precisely match to the drain capacity, the siphon will always start without fail.
I do not like using an aqualifter pump to make sure a siphon restarts because once when a power surge went through our house the aqualifter was fried by it and the siphon did not restart. Fortunately I was home.

People run into problems with HOB's when the above is not followed.

 

[beaslbob]

An HOB overflow can be made from $20 worth of pcv and is just as reliable as any overflow HOB or otherwise.

I also use a maxijet with the "bubbler/aerator" tube to suck out air from the syphon part. One of the two larger sizes. You probably need a power head and that would serve two purposes.

I have attached a schematic type drawing to show the basic idea. You do need to add some way of priming it and adding the maxijet type thing also. But it should point you in the right direction.

Any comments feel free to pm me and of course ask questions here as well.

my .02

 

[Aimulator64]

An HOB overflow can be made from $20 worth of pcv and is just as reliable as any overflow HOB or otherwise.

I also use a maxijet with the "bubbler/aerator" tube to suck out air from the syphon part. One of the two larger sizes. You probably need a power head and that would serve two purposes.

I have attached a schematic type drawing to show the basic idea. You do need to add some way of priming it and adding the maxijet type thing also. But it should point you in the right direction.

Any comments feel free to pm me and of course ask questions here as well.

my .02

I like this idea, but am curious how you construct a box for both inside and outside the tank from diy materials. Your water level in the diagram appears to be above tank level

 

[Richard Hercher]

Watching this thread, I’m looking to add a basement sump to my non-drilled 75G display tank. Any suggestions on how to keep the return pump from flooding the display tank about 14 feet away if a HOB overflow fails?

 

[beaslbob]

I like this idea, but am curious how you construct a box for both inside and outside the tank from diy materials. Your water level in the diagram appears to be above tank level

The top of the tank is above the letters water level (power on). During power out the level falls to the power out level ins is stopped at open to air upsid down u tube. Water is then trapped in the pvc pipe from the bottom pipe in the tank up over the top, down then up again to the open to air point. When power returns the water level increases and at the open to air point if overflows and goes down the drain.

there is no box inside or out. The square around the pipes was just to point out the overflow/water tarp. The entire thing is pvc pipe. The tank's water level is maintained at the "open to air point". You can add another pipe around the in tank to the surface with "teeth" to maintain the tank level there and provide surface skimming. Much like the in tank dams for drilled tanks. Or even just add two elbows and run a pipe back up to the surface.

One person had fun just experimenting with some pvc in the kitchen sink. He seemed proud and amazed when it actually worked. LOL

still just my .02

 

[beaslbob]

Watching this thread, I’m looking to add a basement sump to my non-drilled 75G display tank. Any suggestions on how to keep the return pump from flooding the display tank about 14 feet away if a HOB overflow fails?

Doesn't require an hob to fail. Drains can fail due to blockages for instance.

three basic sump adjustment/tests:

1) insure no floods power out. (display stops draining before sump floods)
2) normal operation returns when power returns.
3) with drain failure (siphon break, blockage, etc) the sump runs dry before display floods.

After the third test, return system to normal operation and mark the water level in the sump. From that point on never never add water to the system above that line.

As you can see the key is for the sump to run dry before the display floods.

FWIW Same thing applies to ATOs. What I recommend is to run the ATO pump signal lines through float switches on the display. And if the display rises above some point turn off the ATO.


my .02

 

[Aimulator64]

The top of the tank is above the letters water level (power on). During power out the level falls to the power out level ins is stopped at open to air upsid down u tube. Water is then trapped in the pvc pipe from the bottom pipe in the tank up over the top, down then up again to the open to air point. When power returns the water level increases and at the open to air point if overflows and goes down the drain.

there is no box inside or out. The square around the pipes was just to point out the overflow/water tarp. The entire thing is pvc pipe. The tank's water level is maintained at the "open to air point". You can add another pipe around the in tank to the surface with "teeth" to maintain the tank level there and provide surface skimming. Much like the in tank dams for drilled tanks. Or even just add two elbows and run a pipe back up to the surface.

One person had fun just experimenting with some pvc in the kitchen sink. He seemed proud and amazed when it actually worked. LOL

still just my .02

I see what you are going for. So essentially this is simply a pipe sticking into the water and secured somewhere else to prevent the trap elbow from dropping below desired water levels. Water level could essentially be fine tuned based on the pipe elevation if kept level. I can imagine putting another upside down elbow in the tank pointing up with slots cut in it for skimming, but would have to get creative with a Guard so I don’t suck in fish.

On a side note, does pvc cement have any negative impact when exposed to seawater?

 

[SAVEtheFISHIES]

I kept African cichlids for years and just made the switch to a full blown reef tank. I have a 125 gallon tank that is not reed ready. I didn’t not drill the tank so I use a HOB overflow. I use the Deluxe CS102 with kid and aqua lifter by CPR Aquatics. It works amazing and keeps your tank at full siphon.