Question on HOB overflow box

[wyvern]

Hi all,
My overflow box has a screw on each side that I guess is to adjust the height of the box that's inside of the tank. Does this controll how much water goes out of the tank and into the sump? For example, the lower the box with the grooves sits in the tank, the more water goes into the overflow and into the sump? I have an overflow with 3 u-tubes but, i can only get 2 to work at a time. If I lower the box, could I get all 3 to work? I know you all are thinking "well just try it..." but, the plumbing would all have to be undone and then reassembled. Thanks for any help.

 

[sign guy]

it shoud help. but first what size return pump do you have and what is your overflow box rated at?

 

[wyvern]

The return pump is rated at 1200gph. Not sure on the overflow. I don't know if the picture will help.

 

[stanlalee]

all moving the inner box up and down does is change the water level in the tank and sump. when you lower the box water only rushes faster momentarily until the sump and tank water level stabilizes again then its back to the same speed (just now you have a lower tank level and higher sump water level). The only way to increase flow thru the overflow box and tubes is with a bigger pump or reduced plumbing loss which is probably not an option. what size return pump do you have? you are going to need something along the lines of 2000gph minimum or more to comfortably feed a three tube overflow box. most 600gph boxes use one, 1200gph two so I assume your's is rated for 1800gph (if the U-tubes are 1" or more in diameter assume this to be the case). how many and what size bulkhead and drain tube(s) are connected to the outer box? what size sump do you have that can handle that kind of flow?

 

[wyvern]

The return pump: 1200gph
U - tubes are: 1.5 inches in diameter. (3 came with the box)
Sump is a Tidepool II. It's a wet/dry with a 13 gallon sump...but there is no way it can hold that much IMO.
The LFS sure saw me comming when I started this

I'm now trying to fix all the problems.

 

[stanlalee]

I'm inclined to believe the 3rd tube was just an extra. With two tubes and the size pump you have everything should work fine without the 3rd tube.

 

[sign guy]

it sounds like your pump is under powerd and the third pipe is breaking the siphone Id look at a larger pump

 

[wyvern]

Ok thanks. Next question. The ovrflow is really loud. In fact, we are now all deaf as we had to turn the volume on the tv way up so we could hear it. I was thinking of doing the durso standpipe thingy. I not sure I can do it with this overflow. I don't think there is a bulkhead. I looks like the pipe from the outside goes in through the bottom and then the pipe with the slots fits into that. I tugged on the pipe with the slots and it won't come out. I was going to buy a durso standpipe (don't think i can make one). Any suggestions.

 

[sign guy]

I dont know how to build them myself search durso in this sites search bar alot of people have built them

 

[wyvern]

ok thanks for the help!

 

[wyvern]

Originally Posted by Stanlalee
all moving the inner box up and down does is change the water level in the tank and sump. when you lower the box water only rushes faster momentarily until the sump and tank water level stabilizes again then its back to the same speed (just now you have a lower tank level and higher sump water level).

So if I raise up the box so that the grooves are just under the water level, then when the power goes out the sump won't overflow? I don't have that problem now, but if I start moving things..... As you can tell, I don't really understand the whole overflow box thingy.

 

[stanlalee]

once the water level drains below the teeth (with the power out) it will no longer go down into the sump. you just have to make sure the sump has enough room to hold that water and make sure the return nozzle has an anti siphon hole to prevent a reverse siphon which will overflow your sump.
it doesn't matter where you move the box. if you move the box up so the grooves are just under the water level in a few minutes the water level should rise in the tank (and lower in the sump). raising the box is going to slow the flow into the box which raises the tank water level because the return pump is still pumping water into the tank at the same rate. this is how you set your tank water level. once you the tank level where you like it you adjust the water in the sump lower or higher to where you want it to be.
you can make a durso type pipe to silence the overflow box. this is what life reef sells for their overflow boxes if they are noisy:

 

[wyvern]

Originally Posted by Stanlalee
you can make a durso type pipe to silence the overflow box. this is what life reef sells for their overflow boxes if they are noisy:

How would I attach it? I don't think I can pull the pipe out.

 

[stanlalee]

the bottom fitting coming out your outer overflow just screws into the pipe inside the outer overflow box (should be a rubber gasket in between. It might be tight but the pic looks just like any other bulkhead fitting. You'd have to cut the pipe extending into the overflow box short and if silencer is too big or small to attach you just get a pvc reducer/adapter from the hardware store. I werent suggesting you buy their's but the pic gives you an idea of how its done/where it goes. I just took a piece of plexiglass and cut it to the opening size of my outer overflow box and cut out a U for the U tube (read I made a lid for the back of the overflow box) and that alone cut the noise down considerably.

 

[wyvern]

I did read the thread when it was posted. I made a lid that night and it helped alot. I can't hear the noise from the overflow at the other end of the house anymore! I was hoping that a durso might reduce the noise even more. The only place I see where there is a joint is where i'm pointing. There is no gasket. From outside the box to that joint is one piece. It looks to be glued in place. Thanks so much for all your help.

 

[stanlalee]

bring your finger down another inch where the pipe meets the clear acrylic. the top pipe should screw into the lower pipe there. it looks like yours might be glued but usually there's just a fitting. IF you are sure your going to fit the silencer (and have it in hand) your gonna have to cut that pipe down to around where your finger is. try holding the pipe you have your finger on with one hand and turning the lowerpipe with your other hand. that has got to be threaded there. almost always is because thats where the hole is drilled. on most overflow boxes the inside pipe just threads into the outer pipe right where it passes thru the hole with a gasket placed on the outside of the box.
I dont really have time because I work tonight but tommorow morning I will post a pic of the spare overflow box I have seperated so you can see what I'm talking about.

 

[wyvern]

I think it's one piece and glued. There isn't a joint where my finger is. I don't have a silencer yet, but will get one. If you get a chance, please post the picture. Thanks for all the help.

 

[stanlalee]

no problem with the help. If yours is glued kinda makes it much harder to modify. Mine simply comes apart as shown:

 

[wyvern]

Well doo doo. Doesn't look like mine comes apart. I guess would have to cut the pipe out of the box. I'm not sure how successful i'd be at that. I think i'd better save up some money to replace the box and plumbing before I attempt that project. And it would probably be a good idea to have someone around incase I cut my finger off or something. :thinking: Thanks again for all your help.