we are beginning a collection of links to internal and external horizontal overflows - design, plumbing, photos, etc.
As the list of links grows... do remember to read to/through some of the older entries. Some great matter there, as these entries are sorted merely by date.
The short summary of principal benefits to an internal weir to mask/capture the drilled overflow holes for a display-sump loop:
- it concentrates the quality of surface overflow water by capturing more proteins via an extended weir rather than allowing less concentrated ("thicker" water) to simply plow through a large, unrestricted pipe opening (see Book of Coral Propagation, Volume 1 and the RC archives for a more detailed description)
- a slight, extended floor (lip) to the internal style horizontal overflow offers an easy pace to store frags or settle with invertebrates that grow to cover and hide this filtration aspect
- an external horizontal overflow is quiet and discreet, while taking up no more space behind the tank than any of a number of other common add-ons (HOB skimmer, HOB fuge, powerfilters, etc.)
- a horizontal overflow is generally regarded as less unsightly and less cumbersome than a vertical overflow tower which takes up precious floor space for the display/rockscape... as well as violating the first rule of water holding vessels: never drill a hole in the floor
http://archive.reefcentral.com/forum...ighlight=calfo
lots of pics of various horizontal overflows
http://archive.reefcentral.com/forum...83#post6093283
Selecting corals to hide internal overflow 11.14.05
http://archive.reefcentral.com/forum...92#post6064592
internal versus external choice 11.9.05
http://archive.reefcentral.com/forum...ighlight=calfo
nice pics and modification suggestions 11.6.05
http://archive.reefcentral.com/forum...68#post5983068
siphon overflow driving the box? Avoid this. 10.26.05
http://archive.reefcentral.com/forum...hreadid=690015
images of acrylic post-prod horizontal overflow 10.16.05
http://archive.reefcentral.com/forum...style+overflow
images of internal horizontal overflow
http://archive.reefcentral.com/forum...49#post5565249
external horizontal overflow 8.22.05
http://archive.reefcentral.com/forum...72#post5545672
Dampening overflow sound/noise: modification
http://archive.reefcentral.com/forum...82#post5377082
CL loop and internal horizontal overflow 7.24.05
http://archive.reefcentral.com/forum...hreadid=619904
http://archive.reefcentral.com/forum...49#post5208549
above added 6/27/05