Russ wrote:
I'm sure that this subject pops up in waves, but as I'm new to online
forums/groups/blogs/whateveryouwanttocallit...

Has anyone had luck with external denitrification filters that don't
need to be fed? If so... Can we talk about the design?... Thanks...


"DSB in a bucket" a la Anthony Calfo worked for us in our 29g. Put 10"
to 14" of fresh, clean sand in a 5 gallon bucket -- any type of sand
should work, even silica-based or pool filter sand, although oolitic
sugar-fine aragonite seems to work the fastest. Drill a bulkhead about
an inch or two higher than the top of the substrate for the water to
flow out from back into your tank/sump. Make sure there's just enough
flow over the sand to keep solids in suspension (pre-filter water
through poly wool or whatever first to minimize detritus build-up) and
advection will take care of the rest.

Anthony has discussed this method in-depth on a few of the popular
reef boards (reefcentral.com, marinedepot, etc...) and also mentions it
in the 2.5 hour lecture video recently posted to the reefvideos.com
podcast.

Ours was higher than the tank, fed it with hose on a ~200gph powerhead
and just let it gravity feed back into the tank. Nitrate went from
20ppm to undetectable in about 6 weeks.
Cheap, effective, and easy to set up (or take down if you have
problems).

FYI I'm looking to start a custom 32 gallon reef in a friends house
and was just playing with a few ideas on ways to make her life easier...

I heard of a 55-gallon tank being used instead of a bucket (and a LOT
more sand obviously), it dropped the nitrates to undetectable in a
2000g display tank at some fish store.