Pure Refugium

Hi I have a three tier system. I want to make the top tank into a refugium. Its function will be a pure refugium to feed I hope corals below it. The dimensions are 875 mm by 600 wide by 300 high with a water level of 250 mm. The question is what substrate do I put in it, how deep?
I have crushed coral available from "sugar grain" size to "chicken bone" size.
Perhaps those of you with experience of refugiums could help?

 

Rod i read somewhere that the size of the gogga's depends on substrate size. If possible try and do a mixture of textures in the same tank obviously partitioned. Also anything from 7.5 to 15cm will do the job i'm sure.

 

use playsand !!! i think this is the most cost effective subtrate available for the marine industry !!!

 

Good questions Rod, I have the same thing I need to ask, setting up a Ref. 1200x60x45 water level will be at about 40...?

 

I am not concerned about the cost. I want the best substrate. If I am going to do it, I want to do it once. My own view is that crushed coral is more natural for the inmates!

 

Well Playsand is what I got to use - sugerfine Aragonite I think would be your best bet but man it would cost like 8k....

 

I am talking crushed coral, not brand name araganite.

 

Personally rod, i`d filter through coarse mesh and use the fine stuff, for a refuge you dont have to go deep, 5cm max.

 

Alan how deep would you say is too deep. In my case I have a water level of 400 or so and can't change that, I am worried if I have too much water ontop of the DSB then alot of debrits will settle on it, so could I go 30cm deep?

 

Ok I'm gonna set it up then gonna come rob you of some sand to seed it with

I'll bring Mr Koekermoer with me as I do not belive he has not seen your tank!

 

Hi reefers

Do not confuse Rod's question here. He want to do a refugium.

Rod from my humble experiense and you must please come and look, go medium to course crushed coral similar to your current substrate in your frag tanks. You know the amount of life in there with shallow water as you want the copes and nutrients to overflow into your display.
Carl

 

Guys, i think it is important to differentiate between refugia and dsb!

1.) refugium---------> Refuge from predation for microlife to proliferate and their population to spill over to your display and serve as a food source for tank inhabitants. And to secondarily serve as a area where nutrients are processed into biomass by the population of microlife..

2.)DSB----------> Deep sand bed with a primary function of denitrification through creation of low oxygen envionment with some microlife which will end up as food in the display to feed corals and fish as a secondry function.

Now to answer your question: Substrate in your refugium should be as fine and soft as possible, as there is a direct correltion between particle size/shape and sandbed infauna. The finer, softer and rounder the substrate, the greater variety and quantity of microlife it will support.

If we follow this trend then surely silty mud/clay should be best??? Like the type found in mangroves swamps.
Well yes it would, IF we were trying to establish mangrove biotopes, ie areas of low flow, major detritus settlement, sulphur producing bacteria at shallow depths and a rich biodiversity. You are however stiving for a refugium to feed a reef, not an area to trap and process masses of nutrients. Personally i feel that mangrove swamps are too far removed from reefs to directly provide food to reefs.

Oh yes, your question............(s)

A few people would advocate the use of a dsb in a refugium, guess the thinking would be that if one cycles nutrients and the other provides live food, them surely the two combined in one space would be better.........

Yes sure, a dsb in a refugium will not negatively impact a refugium...........
HOWEVER, a refugium in a dsb will reduce the efficiency of the dsb.

Remember, with a DSB you are effectively trying to create an oxygen gradient by optimizing flow and reducing settlement of detritus to achieve better diffusion.

A popular way to add surface area for critters to colonise (and some added nutrient removal) to a refugium is by using some algae, preferrably something like chaeto. By having algae in a refugiums, you are slowing flow pathways and increasing detrital settlement.

I.e. interfearing with flow pathways and diffusion.

IMHO a pure refugium (as you are planning) would consist purely of an environment free of predation, which would encourage proliferation of micro and meofauna.

The optimal substrate would be aragonite, as there is no other substrate which can compete in terms of surface area and shape. (of course budget comes in to play here) Stick to a shallow sandbed, and keep a seperate dsb, with higher flowrates than in the refugium. Some small pieces of liverock should be included to provide extra biodiversiy and surface area.

If you want to, add some chaeto, although i believe this is best used in a seperate area as not to impede flow or cause too much detrital settlement an the shallow sandbed of your fuge.

Large pieces of crushed coral is an effective detritus trap, which will have to be siphoned regularly, impeding development of microlife colonies. (lets not even look at the potential as a no3 factory)

 

What would the lighting needs be for a fudge? And what period?
Nice tread..

 

Hi, thanks to all for the input. Starting it up today, by cutting the main feed to the top tank, and putting in a dedicated pump to feed the refugium, this begs another question. What flow should I give it?

 

Rod according to Anthony Calfo, you should consider moderate to strong but deffused water flow. For those of you that want to check this its on page 66 in his book "Reef Invertebrates" He also believes if the water flow is to slow we will create something almost to the effect of stagnant pools, not good as you can imagine.

 

Irie Ivan

Great post and to the piont.

 

It all depends on what you would like in your refugium. There is no doubt that lit refugiums house a higher populations of microlife.... At the potential expense of having to deal with algae.

Low output lighting is sufficient, unless you intend housing algae for nutrient removal, instead of increased pod real estate.(and reduced flow..)

Lighting a refugium on a reverse daylight cycle, will definitely help a great deal towards combatting night time pH drop in ur system, but this has always seemed unnatural to me...

With enough flow from tank to sump and heavy skimming = air gas exchange = oxygenation of water, I have a pH swing of only .05 at night.

 

Dammit, now you have me really thinking !!

Nice thread

Muz