Down Draft Skimming

[fishfry101]

Has anyone tried this method and does it work. My only question is how long does the vertical tube have to be for the water to foam
ETS's & Down-Draft Skimming
Attachment 237192
By Don Carner
ETS's & Down-Draft Skimming
Another,even simpler design became popular just a few years ago. The "ETS" (Environmental Tower Skimmer) was introduced to the hobby. Also known as Down-Draft skimmers, these models use a long tube connected to a sump with nothing more than an internal baffle plate and a drain valve. Inside the long vertical tube, bioballs are placed to diffuse the high velocity water that is injected at it's top. As the water shoots down over the bioballs, it is smashed and resmashed on the tower of bioballs. By the time the water reaches the sump at it's base, the water is a white sea of foam. The baffle inside the sump creates dwell time and allows the protein-rich froth to rise up into a wide-mouthed tube with the collection cup mounted above it. These designs can process huge volumes of water and are favored by big tank owners.

 

[reefkprz]

yes they work very well. they are generally large units anywhere from 3 to 6 feet of downdraft on average and are generally used for larger tanks, or people with space to spare. they are a very effective skimmer. as the down draft unit provides bother aerobic bacterial growth and fractionation for skimming. the closest downdraft skimmer to me the downdraft unit is 8 feet tall.

 

[fishfry101]

Thanks - I was thinking of incorporating this into my sump, however if it takes a 3 to 6 foot drop that wouldn't work in my build. oh well!!!

 

[natclanwy]

They don't have to be that tall, ETSS has skimmers that are ~22 tall. I don't know that they are as effective as their larger cousins though. AquaC's foam injection method is similar and also has a compact design.

 

[reefkprz]

I dont know how effective the compact units are either, with the short drop the contact time has got to be more limited.
the 8 footer at the university skims (rough estimate here) about 20 100g fry tanks for raising the aquacultured fish so i know the units are effective the collection cup is roughly the size of a five gallon bucket. and boy does it pull some gunk, the last time I went over there I was actually discussing its performance, and Soren was telling me he had tried another large skimmer with a mesh wheel and the down draft out pulled the other for the couple months he had them both running. I dont know how scientific an observation it was but they went from considering removal of the downdraft to save space to keeping it because it performed so well comparatively. they figured it was worth the space sacrificed.

 

[atrain5851]

i have seen the smaller downdraft skimmers used on tanks as big as 210 gallons fully stocked and is very effective.