External overflow questions....

[saltwaternewb]

Been thinking about whether to drill or not to drill and in an effort to keep a clean equipment free (as much as possible) tank I was wondering about a reverse overflow. Instead of have an overflow box IN the tank and one large hole drilled, how about a line of several small holes that drain in to an overflow box attached to the back on the OUTSIDE of the tank, the the box be drilled and the overflow is inside of that box in the form of a standpipe. My question would be how many holes (four?) and what size should they be (1/4") ? Also, I would do two holes for the return. What size holes should be drilled for the return? I am sure it has been done like this a number of times but I have not seen anyones tank with this setup so if anyone knows of some, could you please let me know and maybe post a link so I can check them out. Thanks.

 

[saltwaternewb]

Anyone have any thoughts on this?

 

[fly guy]

is the tank acrylic by chance??

If so you could do the creme de la creme...and go with an external toothless coast to coast overlfow. nothing in the tank but reef, and the absolute best surface skimming ability possible.

One of my tanks is set up like this...and i wish the other was. It could be done with glass as well but i would never recommend anyone doing it after the tank was built as the entire back wall needs to be shorter than the other three.

anyway......you might want to check out the overflow thread two posts below this at the moment...I posted soemthing i did for a friend that surface skims well, could be done with only one hole drilled and the actual part of the overflow in the tank isnt really visible or obtrusive at all. all that is needed is PVC.

Your hole idea would surely work, but would require a whole lot more holes than 4 1/4" holes, and i say that having no idea how big your tank is. Figure this.......you want any overflow set up to have at LEAST 150% capacity of how much water you are actually moving. a 1" hole in theory has the ability to drain 600 gph. I say "in theory" as mounted on teh back wall like that with the water level moving with flow.....you wouldnt get that out of it. it will take roughly 16-1/4" holes to equal the surface area of 1-1" hole. So if you were planning on running 600 gph thrpough your sump......and wanted to do it that way, I would suggest drilling 30+ 1/4" holes if 1/4" was what you wanted. If your tank happens to be a fairly thin walled glass tank........not exaclty all that safe to try

 

[saltwaternewb]

It is acrylic and will be about 26g. I just guessed 1/4" holes but after drawing a couple different size circles on paper, 1/2" holes look like they would be better but not so big to be distracting. I even thought about a slot but the idea of the majority of the rear panel being lower than the other three is very intriguing. I guess any tank that can be converted though by adding a new shorter rear panel to the inside of the tank. I am hoping to do another larger tank sometime around the end of the year so this idea might be a good one to try.