Over Flow BoX

[amehel0]

Hey,one thing that bothers me is why do people use oever flow boxes,

Down sides
Unsightly
Tanks Space
Make nosie
Need durso standpipes most of the time
Take in fish

Upsides

They allow for a little bit more flow through one hole but very little extra


So why?

[kar93]

A dusro is used to stop the noise and if covered the fish do not jump in there. They allow water to flow to the sump without having to risk a siphon stopping as it would on a HOB overflow. External overflows can be used as to not take up space in a tank. You build fish tanks? I assumed you would know all of this.

[amehel0]

yes but why not drill holes in the back at the top?

[Doahh]

Because it's NOISY... and it takes up about 6-8" behind the tank. People say it may be benificial to have it but I'm thinking no... With the overflow I have it also has very little surface area for water overflow.
I would rather have the in the tank thing because if designed right they are:
Silent
Large overflow area
Never take in fish
Silent (oops mentioned it again)
and they can be hidden by corals

[Doahh]

I should also add to get as much flow as 600+ GPH that in in tank overflow box could handel with a 1" hole I need 1.5" PVC

[amehel0]

yes but if used correctly holes in the back are more silent then an overflow box. i understand that it takesspace behid the tank.

[sjm817]

You must have a weir to surface skim. The water must "fall" into the box to carry surface contaminants with it. With just a hole on the back, you get no surface skimming. The water just slides through under the surface contaminants.

[Doahh]

I use an upturned elbow on mine...
There is NO way to get an overflow like that as quiet as a built in one...

[das75]

Been playing with a Herbie type drain on a 33g with no overflow chamber, just a pipe coming up off the bottom of the tank. Seems to work okay and was silent.

See no reason why couldn't have the bulkhead on the side near the top then with an up-turned elbow.

As pointed out though, a overflow does give that surface skimming.

[demonsp]

I hate mine and im sure my parrots at night hate it more.With a highly modified stockman.

[sjm817]

<a href=showthread.php?s=&postid=12495021#post12495021 target=_blank>Originally posted</a> by das75
Been playing with a Herbie type drain on a 33g with no overflow chamber, just a pipe coming up off the bottom of the tank. Seems to work okay and was silent.

See no reason why couldn't have the bulkhead on the side near the top then with an up-turned elbow.

As pointed out though, a overflow does give that surface skimming.
So does an up turned elbow. Not a lot, but its there.

[amehel0]

well on my90 the holes are abot an inch off the top and it skims the surface. i just dont get why people use them there more hassle then there worth

[Doahh]

How is it more of a hassle than a bulkhead at the top... it's more elbows and plumbing is more complicated?

[sk8rreefgeek]

not to mention some tanks are tempered

[gsxunv04]

I use an overflow so I can utilize a sump, which means I can use an in-sump skimmer and a fuge. I dont have a drilled tank so it was the only option.

PS FWIW my HOB overflow is virtually silent, I use gurgle busters

[Doahh]

Wait... are we talking about HOB overflows or IN TANK overflow boxes like AGA Megaflows?

[sjm817]

<a href=showthread.php?s=&postid=12500056#post12500056 target=_blank>Originally posted</a> by amehel0
well on my90 the holes are abot an inch off the top and it skims the surface. i just dont get why people use them there more hassle then there worth
If its just a hole in the back (bulkhead) with a horizontal exit flow, I highly doubt you have good or any surface skimming, since the physics of the design say that you wont. I've set up many systems like this and they dont skim. You have to have a vertical drop. Even my 65G fuge just has a hole in the back as you call it. It had an accumulation of film on the surface until I added a simple overflow box that provided surface skimming. It cleared up in less than 1 hr.

This is why overflow boxes (weirs) are used. Its a well proven, very standard design.

[gsxunv04]

I thought were talking about HOB's, my bad...