Overflow Question

luke33 · 12/15/2006, 02:35 PM

I'm fairly new to the hobby and don't have a sump up and running yet. I have a 125G fowlr tank and have my sump/refugium design all ready, but my tank isn't drilled. I've heard nothing but horror stories of HOB overflow's and haven't heard anyone speak about this. Could i hook up a internal pump to my intake and push the water into the sump this way, then have an external return? If not why not, because it seems like you wouldn't have to worry about overflow this way if power turned off and on? Maybe a few thousand people have asked this but hopefully someone will answer me.
THanks a ton!

staticx · 12/15/2006, 03:01 PM

Not a good idea to have a pump in your tank pushing water out and then another pump returning water. It would be too hard to get the pumps to match each other. You would be more likely to have a overflow with two pumps then you would with a hang on the back overflow. Hang on the back overflows are fine to use, You just have to make sure your sump can hold enough water if your pump stops working. Some people say they loose the siphon but I have never lsot the siphon. Do you have a glass tank or acrylic

sir_dudeguy · 12/15/2006, 03:12 PM

honestly i see no reason to fear using HOB overflows. I've got one on my 40 and i honestly dont get why people get the impression they're not safe. I unplug my return pump...the water stops going into the sump as soon as the box in the tank and the box behind the tank equalize (so maybe like half a gallon goes into the sump after i turn the pump off....no flooding there..)

I plug the pump back in and it starts going again. The only way i can think of that there would be a problem is if you somehow have air getting into your U-tube to break the siphon...but theres not even any air/bubbles anywhere near my over flow, so again, i dont see where that comes from.

The only thing that would possibly start leaking would be like the bulkheads or if a pipe isnt on tight enough...but heck..my old tank itself started leaking for no apparent reason. So if someone is worried about the actual plumbing starting to leak...why not worry about the tank leaking too lol?

Like staticx said tho, you do not want a pump shooting water down to your sump, and another shooting it up back to the tank. Disaster waiting to happen right there....One will eventually slow down a bit more than the other (if you ever did manage to get them putting out equal flow after you calculate the head loss that is) and there will be a flood.

sir_dudeguy · 12/15/2006, 03:13 PM

oh and on that last bit...what if one pump dies completely for no reason? I've had several pumps do that...just die. But the other still keeps going? Think about that

luke33 · 12/15/2006, 03:20 PM

I have a glass tank. Very thick glass. My concern would be if i had an overflow and the siphon stopped after a power outage, there would be a flood once power started. I understand the extra sump area for just in case. Thanks for the feedback, but i'm still curious if anyone has ever tried this and if there is a way to make it safe.

luke33 · 12/15/2006, 03:26 PM

What type of overflow would you suggest for 1200-1800 gph that would have a syphon that would not break? Thanks!

aquarius77 · 12/15/2006, 03:33 PM

https://www.aquatraders.com/index.as...ROD&ProdID=146

they ship fast and wont let you order something that is not in stock, cheap too!

luke33 · 12/15/2006, 03:56 PM

Thanks aquarius! Thats a ton cheaper than a cpr! Nice

12/15/2006, 02:35 PM	#1
luke33 Moved On Join Date: Dec 2006 Location: Indiana Posts: 8,375	Overflow Question I'm fairly new to the hobby and don't have a sump up and running yet. I have a 125G fowlr tank and have my sump/refugium design all ready, but my tank isn't drilled. I've heard nothing but horror stories of HOB overflow's and haven't heard anyone speak about this. Could i hook up a internal pump to my intake and push the water into the sump this way, then have an external return? If not why not, because it seems like you wouldn't have to worry about overflow this way if power turned off and on? Maybe a few thousand people have asked this but hopefully someone will answer me. THanks a ton!

12/15/2006, 03:12 PM	#3
sir_dudeguy Registered Member Join Date: Mar 2006 Location: Portland, OR Posts: 10,841	honestly i see no reason to fear using HOB overflows. I've got one on my 40 and i honestly dont get why people get the impression they're not safe. I unplug my return pump...the water stops going into the sump as soon as the box in the tank and the box behind the tank equalize (so maybe like half a gallon goes into the sump after i turn the pump off....no flooding there..) I plug the pump back in and it starts going again. The only way i can think of that there would be a problem is if you somehow have air getting into your U-tube to break the siphon...but theres not even any air/bubbles anywhere near my over flow, so again, i dont see where that comes from. The only thing that would possibly start leaking would be like the bulkheads or if a pipe isnt on tight enough...but heck..my old tank itself started leaking for no apparent reason. So if someone is worried about the actual plumbing starting to leak...why not worry about the tank leaking too lol? Like staticx said tho, you do not want a pump shooting water down to your sump, and another shooting it up back to the tank. Disaster waiting to happen right there....One will eventually slow down a bit more than the other (if you ever did manage to get them putting out equal flow after you calculate the head loss that is) and there will be a flood. __________________ TAKE...LUCK!!!

12/15/2006, 03:13 PM	#4
sir_dudeguy Registered Member Join Date: Mar 2006 Location: Portland, OR Posts: 10,841	oh and on that last bit...what if one pump dies completely for no reason? I've had several pumps do that...just die. But the other still keeps going? Think about that __________________ TAKE...LUCK!!!

12/15/2006, 03:01 PM	#2
staticx Moved On Join Date: Nov 2006 Location: oregon Posts: 825	Not a good idea to have a pump in your tank pushing water out and then another pump returning water. It would be too hard to get the pumps to match each other. You would be more likely to have a overflow with two pumps then you would with a hang on the back overflow. Hang on the back overflows are fine to use, You just have to make sure your sump can hold enough water if your pump stops working. Some people say they loose the siphon but I have never lsot the siphon. Do you have a glass tank or acrylic

12/15/2006, 03:20 PM	#5
luke33 Moved On Join Date: Dec 2006 Location: Indiana Posts: 8,375	I have a glass tank. Very thick glass. My concern would be if i had an overflow and the siphon stopped after a power outage, there would be a flood once power started. I understand the extra sump area for just in case. Thanks for the feedback, but i'm still curious if anyone has ever tried this and if there is a way to make it safe.

12/15/2006, 03:26 PM	#6
luke33 Moved On Join Date: Dec 2006 Location: Indiana Posts: 8,375	What type of overflow would you suggest for 1200-1800 gph that would have a syphon that would not break? Thanks!

12/15/2006, 03:33 PM	#7
aquarius77 Moved On Join Date: Sep 2006 Location: Highland, Il Posts: 2,198	https://www.aquatraders.com/index.as...ROD&ProdID=146 they ship fast and wont let you order something that is not in stock, cheap too!

12/15/2006, 03:56 PM	#8
luke33 Moved On Join Date: Dec 2006 Location: Indiana Posts: 8,375	Thanks aquarius! Thats a ton cheaper than a cpr! Nice