Weir or No Weir Overflow box

[ReeferMan]

I am building a slim overflow box and was wondering if someone has use one without weirs. I saw some people swearing by them, but the posts were from years ago. Obviously it would be easier to make without. 

[AlanM]

What do you mean by making one with no weir? The water has to "overflow" over something, which to me means a weir.  With teeth or without.  Do you mean maybe putting an elbow with a strainer on the inside of the tank or something like that?

[YHSublime]

I think they mean teeth. You’d probably want the teeth just to keep snails/fish/anything that could block your drain without them probably will. There was an OG that used a plastic wall mail holder once, but I don’t suggest it!

[ReeferMan]

No teeth. People used gutter guard to block fish and snails. Said it skimmed better. 

[Gatortailale]

ReefSavvy makes a slim one called a ghost overflow. It has teeth on slim inside portion that is magnetic and removable for cleaning. Love it on my 36x30x24 ReefSavvy tank

 

https://www.reefsavvy.com/ghost

[AlanM]

I had a toothless weir on my 75g tank.  It was very successful, but I did get stuff going over it all the time.  Even a fish or two.  It wasn't ideal.  I eventually used gutter guard which did help somewhat.  It does allow for fantastic flow over the overflow, and is dead quiet, but you pay the price in livestock somewhat.  I recommend teeth now.  It's harder to do diy, but works better.  It cuts the flow down by more than the percentage area obscured by the teeth because of the extra surface tension, but over time can be just as quiet because slime builds up and calms down the turbulence.  That said, a DIY toothless weir can work just fine.  If you make it wide enough then the height over the weir can be very small for fairly high flow rates to lessen the chance of a fish going over.  Snails will, though.  Especially nerites.

[AlanM]

FYI, I made a weirflow google sheet long ago to calculate how high the water level will be over the toothless weir for a given width and flow rate.  

 

https://docs.google.com/spreadsheets/d/1zguJ29X4CIA6SjvPmMsB-ab2QU3ndKfI4avp4PSO-PM/edit?usp=sharing

[ReeferMan]

Thanks alot guys for the info