Calling all HOB overflow box users! Question???

vlangel

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I have successfully used HOB overflow boxes since 2004 and have never had one lose a siphon resulting in a flood. I just match the flow capacity of the drain with the flow coming out of the nozzle from the return pump. However, the one weakness of a HOB overflow box is that with 1 standpipe and drain if it gets clogged there will be a flood. That has never happened to me but I wondered if anyone has come up with a way to alleviate that possibility. I see Eshopps sells a dual HOB overflow box. It appears it has 2 standpipes and drains. I wonder if its possible to cut one shorter than the other so one is a primary and one is a secondary? Anyone ever tried that?
 

tritonpower

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I used it but had trouble keeping the siphon in the 2nd tube. One would always loose siphon so I ended up just using the one tube and giving up on the 2nd. I did need to put tape over the tube because it was somewhat clear and algae grows in it and it started to clog.
 
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vlangel

vlangel

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I used it but had trouble keeping the siphon in the 2nd tube. One would always loose siphon so I ended up just using the one tube and giving up on the 2nd. I did need to put tape over the tube because it was somewhat clear and algae grows in it and it started to clog.
Does your overflow box have 2 drains or just 2 U tubes? I am thinking of only using 1 U tube and running as much flow through it as 1 drain will handle. I will modify the the 2nd drain's standpipe to be slightly higher. That way all the water should go down the drain with the shorter standpipe, unless it gets clogged. In that case the water will rise a little more in the outside box until it goes down the higher standpipe and drain. Does that make sense?

And yes, I have tape on U tube also to keep algae from growing inside it.
 
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vlangel

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vlangel

vlangel

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Mine had 2 drains
So was one of the drain standpipes higher than the other so that you had a primary and an emergency? The way I am picturing it needing to work is a taller standpipe in one of the drains does not get used because all the water would be going down the drain with the shorter standpipe. The drain with the taller standpipe would only get used if the other drain clogged and water began to rise high enough to flow into the taller standpipe.
 
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Dom

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I have successfully used HOB overflow boxes since 2004 and have never had one lose a siphon resulting in a flood. I just match the flow capacity of the drain with the flow coming out of the nozzle from the return pump. However, the one weakness of a HOB overflow box is that with 1 standpipe and drain if it gets clogged there will be a flood. That has never happened to me but I wondered if anyone has come up with a way to alleviate that possibility. I see Eshopps sells a dual HOB overflow box. It appears it has 2 standpipes and drains. I wonder if its possible to cut one shorter than the other so one is a primary and one is a secondary? Anyone ever tried that?

I have the Eshopps PF-1200 which uses 2 standpipes. On one side, I have a straight standpipe as an emergency drain and on the other side, a Durso. This overflow uses (2) U-Tubes going over the top. I've eliminated one as it is installed on a 40 gallon display.

I'll post pictures later.
 
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vlangel

vlangel

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I have the Eshopps PF-1200 which uses 2 standpipes. On one side, I have a straight standpipe as an emergency drain and on the other side, a Durso. This overflow uses (2) U-Tubes going over the top. I've eliminated one as it is installed on a 40 gallon display.

I'll post pictures later.
Thank you Dom, that would be so helpful. Are you satisfied with the performance?
 
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Dom

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Thank you Dom, that would be so helpful. Are you satisfied with the performance?
IMG_2526.jpg
IMG_2527.jpg

 
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Dom

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Thank you Dom, that would be so helpful. Are you satisfied with the performance?
Overall, yes. It is much quieter running it this way. But I still worry about a lost siphon in the U-Tube and resulting flooding.

Beside the flooding, RODI top off water will continue to fill the sum and pump it into the tank, dropping the salinity.

Any ideas about how to prevent it?
 
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vlangel

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Overall, yes. It is much quieter running it this way. But I still worry about a lost siphon in the U-Tube and resulting flooding.

Beside the flooding, RODI top off water will continue to fill the sum and pump it into the tank, dropping the salinity.

Any ideas about how to prevent it?
Is your U tube black? Mine is clear so I can see if it is running without any bubble build up. I have been using this overflow box for 8 years but I have been using overflow boxes for 20 years on my different tanks. As long as the flow coming from the return nozzle going into the tank matches the maximum drain capacity, bubbles should not build up.

I have only a 1 gallon reservoir and with my current 56g display and 30g sump (bother are covered to slow evaporation) should the ATO fail and stick on it will only dump 1 gallon of top off water into the system. That is not enough to significantly impact my reef.
 
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jattinella

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Overall, yes. It is much quieter running it this way. But I still worry about a lost siphon in the U-Tube and resulting flooding.

Beside the flooding, RODI top off water will continue to fill the sum and pump it into the tank, dropping the salinity.

Any ideas about how to prevent it?
On my 75 gallon I am using the PF-1200 overflow configured as a herbie system. One standpipe (the overflow) at 5 inches tall and the other standing at 2.5 inches tall. I use just one siphon tube since I am running at approx 450 GPH. Keeping a good flow in the siphon tube prevents any bubbles from accumulating. I have the foam sleeve on the lower standpipe to prevent clogging the gate valve. This arrangement runs very quiet. In order to prevent a flood on a siphon failure (which has never happened in over 8 years), I have a float switch in the last chamber of the sump that feeds the return pump and ATO. If a siphon failure occurs, the last chamber in the sump will be depleted quickly. I run my water level in the main tank just at the level of the bottom of the plastic rim. Doing the math shows that is over 4 gallons of space. The last chamber of my sump holds less than 4 gallons which will trip the float value before the main tank floods. When the return pump turns off, so does the ATO pump. I have tested this and seen it work as expected.
 
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vlangel

vlangel

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On my 75 gallon I am using the PF-1200 overflow configured as a herbie system. One standpipe (the overflow) at 5 inches tall and the other standing at 2.5 inches tall. I use just one siphon tube since I am running at approx 450 GPH. Keeping a good flow in the siphon tube prevents any bubbles from accumulating. I have the foam sleeve on the lower standpipe to prevent clogging the gate valve. This arrangement runs very quiet. In order to prevent a flood on a siphon failure (which has never happened in over 8 years), I have a float switch in the last chamber of the sump that feeds the return pump and ATO. If a siphon failure occurs, the last chamber in the sump will be depleted quickly. I run my water level in the main tank just at the level of the bottom of the plastic rim. Doing the math shows that is over 4 gallons of space. The last chamber of my sump holds less than 4 gallons which will trip the float value before the main tank floods. When the return pump turns off, so does the ATO pump. I have tested this and seen it work as expected.
Do you have any pics of your overflow box and sump?
 
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