Cyanobacteria are the most primitive organisms known to have a daily cycle of gene activity. Even without light, they continue to switch on genes for photosynthesis during the day.
A refugium is used such that the populations of such fauna as isopods, amphipods and copepods is not totally eliminated by preditation by the fish.
The fauna has a place to live and multiple without being eaten by the fish. It is quite easy for the fauna to move freely into the main display tank in some way, but such that not all the population is lost.
Until now the only sort of refugium that you can find in the books is either one as a completely separate tank plumbed to the main tank, one that hangs on the side of the main tank, or one situated within the main display tank as a separate section. This is all fine and dandy, but it would be better if there was a more simple solution. One day someone was talking on the #reefs IRC channel that they were going to put a PVC pipe in their tank with the strainer type end caps to act as a refugium. And from that the following refugium was developed.
Side view of the in tank refugium.
All it involves is as a cage of eggcrate situated in the main display tank, with the eggcrate acting as a substrate for algae to grow on for the fauna to feed on, and to keep the fish out and eating the fauna. Thanks to the people that were involved in the idea development.
All this is required to build it is:
? x ? Eggcrate
This was left over from when making up the reef support that is in the sand bed.
20 x Cable Ties
These are to join the pieces of eggcrate together. Perfect for the job, making the joins secure, and if required to pull it apart by cutting the ties.
The final design that was settled on is very much like a house. A sloping roof is used to try and maximise the surface area that will get light and allow more algae to grow. Two levels of eggcrate are placed withing the roof section to ensure that no fish can get in, and also provide additional surface area. Within the bottom section, live rock can be placed, to provide a more natural region where some additional fauna can live.
Firstly 4 pieces of eggcrate 10cm wide and 20cm long were cut out. Three of these make up the roof, and the remaining one the floor. The three were fitted together into a triangular shape, using two cable ties per join. Inside this the two additional levels were fixed, being 3cm and 7cm wide, and 20cm long. Two walls were then cut out, being 6cm wide and 20cm long. These were attached then the floor, and that is all that is to it. This particular size was choosen such that it fits in a spot behind the reef and next to the overflow. Fragments of live rock were also packed into the bottom section, this also helps to weight down the structure as eggcrate is slightly bouyant.
Front view of the in tank refugium.
So, did it work and was it a success? I would say that it did help, but now I think there are better ways of doing it. It actually provided a very good grazing area for the mandarin that I had, since it was the only fish that could fit through the eggcrate holes. And it did tend to spend a significant amount of time feeding in and around it. If I was to do it again, it isn't in the tank currently and hasn't been for several years, I would set up a separate tank. Or, if it has to be something like this again, something more like a rectangular box of a larger volume.
Comments
DIY In Tank Refugium Written by
on 2007-08-31 12:08:14Hi,
I am very interested with this article on DIY In Tank Refugium. I just have a question about the plant, like caulerpa algae, that is grown inside this in tank refugium, I read somewhere that the algae might contain highly toxic phosphate as that is the nutrient that is feeding on the plant. So there are not suitable for any fishes ?? If the plant is in the tank and other fishes may pick on them .. do you think it is safe for the fishes ??
Re: algae Written by
on 2007-08-31 12:10:10Phosphate is not toxic to fish. Reason phosphate has a bad name as it can be the limiting nutrient for problem algae, so if you reduce the level then you can help to control the problem algae, if you have some.
Not all fish will eat it though. Plus, take care as it is actually illegal to have Caulerpa taxifolia in some areas of the world.
Write Comment
Please keep the topic of messages relevant to the subject of the article.
Personal verbal attacks will be deleted.
Please don't use comments to plug your web site. Such material will be removed.
Just ensure to *Refresh* your browser for a new security code to be displayed prior to clicking on the 'Send' button.
Keep in mind that the above process only applies if you simply entered the wrong security code.
