Hi,

I am starting to get a tank set up for an octo and had a question about the sump. Is it possible to keep food for the octo, like crabs and shrimp, in a sump or do I need to set up a refugium as well. If this is the case, how do you set up the refugium and sump, and which needs to come first in the terms of water flow.

i believe some of the owners here have kept crabs in a partition of their sumps without a problem. i think water from your tank needs to hit the refugium before the sump in most cases, because you want it to go through the fuge while all the algea and bacteria are still in the water. all the stuff you want to thrive in your refugium gets removed from the water in the filtration in the sump.

but i've got little experience. hopefully others will chime in and fill in the gaps.

Octopus tanks do not need a refugium. It is fine to keep food in the sump as long as you don't lose it in there and be sure you can catch it again. Refugiums usually go in the sumps, so I don't understand what you mean by before or after. Also refugiums are pretty useless if you put animals in with the algae; the pods that you are giving a refuge to get eaten by what you put in there. Macroalgae is pretty much all you should have in the fuge.

Thanks for your help mike and shippo. Also, what i meant by before or after is the water flow. As in should the water flow into the from the tank to the refugium and then to the skimmer, or vise versa. But if it is OK to keep some food sources in the sump then I wont worry about a refugium. Thanks for your help.

It doesn't matter where you put it; it depends on how your sump is designed. It will still function as a filter for PO4 and NO3 wherever you put it. You have to make sure you have a sufficient light for growing the plants if you do a refugium.

Also, You're welcome :)

I could be wrong, but from what I've read refugiums are not just for growing plants, that is just one possible purpose of a refugium. Refugiums are a refuge from predation, and are for anything that will not survive in the main tank. All I would want in my refugium would be food for the octopus, dont really care about plants and algae. That way I could keep a supply of live food and won't have to make trips across town to buy live crabs and etc except for a couple times a month.

I have a HOB refugium. It's got a wad of chaetomorpha in it about 7x4x10 inches... fits snugly inside it like a filter pad, along with a 4 inch deep sandbed and live rock rubble. I keep a 20" fluorescent strip light over it, run the light 24/7 when I don't have an octopus in the tank because it raises the temperature significantly. Otherwise I run the light only at night when the display lights are off.

At any given time I can see dozens upon dozens of amphipods running around. But that's also where the bulk of my bristleworms are. Sometimes I keep soft coral frags in there. I have some Hermits in there too. I occasionally pull the macroalgae and rocks out to syphon out any excess junk buildup.

It might not be a necessity, but my tank never has any cycle issues. A refugium is a wonderful addition to a tank. If you do decide to use part of your sump as a refugium, at least go with some live rock rubble and macro along with whatever live food items are in there. It will benefit your tank.