"Bryan" wrote on Wed, 30 Aug 2006:
I'm designing a sump that I want a protein skimmer an refugium in. I plan
on planting the refugium to further eat up the phosphates. Should I put
the protein skimmer before the refugium or vice versa? Does it really
matter.

Doesn't really matter, since neither purifies the water with a single pass.
You need tank water to constantly stream past both kinds of "filters", and
each only cleans the water a little bit on a single pass.

But if you could really do it either way, you should put the refugium first
and the skimmer second, for filtering purposes. Both consume many of the
same kinds of organics. Basically, just like on land, plants and animals
are in many ways complementary. In your reef system, the fish and macroalgae
are going to be opposites. Plants consume far more animal waste than just
phosphates. They take in CO2 and make O2; they use nitrates as a fertilizer;
etc. So you want the water entering the refugium to be as "dirty" as possible.
Hence, put it immediately after the tank, and before the skimmer, in your
water flow.

That advice is for the plants. Note that refugiums are also typically sources
of copepods and amphipods, which are fabulous live food for your reef fish and
corals. For that purpose, it's a shame to grow some 'pods in the refug, only
to have them sucked up into a downstream skimmer and killed there. Some
people even claim that the return pump is too much, as it might chop up 'pods
making their way downstream. The absolute ideal for a 'pod-factory refugium
is to have it physically above the main tank, and have a slow flow of water
only gravity-drain into the main tank. That way, the maximum rate of 'pods
can grow in the refug and fall, alive, into the main tank as food.

Summary: it doesn't really matter. But if filtering is your main concern,
might as well put the refugium first, and skimmer second.

-- Don
__________________________________________________ _____________________________
Don Geddis http://reef.geddis.org/
In judo: When pushed, pull; when pulled, push.
In aikido: When pushed, turn; when pulled, enter.