Refugium sizing

[Reelfish]

I have a 120 reef tank with a rubbermaid sump. I am adding 2 50g and 3 15g tanks to the system so one could be used as a fuge. I originally was set on using a 50 but now that they are on the stand I was thinking maybe I could use a 15 somehow any thoughts.
Bob

[gman0526]

It would work regardless, just might have to trim down macroalgae faster due to limited space.

BTW what do you want to attain by adding the refugium? There's different kinds... ;)

[Reelfish]

My main reason is to starve algae growth in the display. I will also hope to add water stability with the sand bed, feed my filter feeders and Herbivores and a home for something different possibly. I am leaning towards the 50 because of size.

[Elsherst]

Bigger is always better.

[chineseknife]

In all actuality, in order for your refugium to have any "real" effect on a large scale, you'd need a fuge about 3 times the size of your display. That's alot of macroalgae.
Although, some amount of scrubbing in a smaller area is better than none.

[gman0526]

How is that? As long as the volume of exported nutrients is the same there should be no difference as far as the size of the refuge is concerned. You take 2 pds. of chaeto from a 15 gal fuge or from a 100 gal fuge is still the same volume.

[chineseknife]

Yes, but would you only keep 2lbs. in a 100g fuge? 100g would allow more chaeto which would, in effect, scrub the water of more nutrients.
Now suppose you have a 10g nano. Attach a 100g fuge to that and you are rockin'.
Now add the same fuge to a 225g tank. Which tank do you think will be better served?
Now lets reverse that.
Add a 10g fuge to a 100g tank and see how much exportation actually goes on. And on the flipside, add a 225g fuge to a 100g tank and that fuge will scrub more nutrients, faster.
My point here is that, and as stated in post #4, bigger is always better.

[gman0526]

Macro algae growth is going to be relative to the amount of nutrients in the system not to the amount of macroalgae in the fuge.

[chineseknife]

Would you agree that 2lbs. of macro won't scrub as much as 10lbs., regardless of how much nutrients are in the water?
Little theory here...
Lets say your tank is at 20 with nitrates. Throw a 15g fuge with 2lbs. of macro in there. Now lets say that 1lb. of macro will drop your nitrates 2ppm everyday. So that would mean that to get the tank to 0 nitrates you'd have to go 5 days to remove all the nitrates.
Using the same theory, but with a 100g fuge with 10lbs of macro in it, it would take about a day to remove the nitrates.
Lets say that both of these instances had a 55g display tank, which do you think will be scrubbed more, and faster?
I'm not saying there aren't things that can "speed up" or slow down the scrubbing process, including space and lighting, and flow as well.

[icereefer]

I guess myself I would agree with the bigger the fuge the better , because for one more water volume is always better, as for macro algea know matter how much you have it's only going to export so much if you have to much it will only grow so fast. smaller refuges get better growth usually but need to be cropped more, as in a bigger refuge it tends to look like your getting better results because of more water volume the more water volume, the bigger your micro algea population you'll have,which in sense means your eco system will be stronger and more stable which makes it "look" like larger amounts of macro is better.

[chineseknife]

Hence my reasoning that a 15g fuge on a 125g tank won't do much. It'll export some, but to truly be effecient at what it does, the 50g would be much better.

[Reelfish]

The display does not have a fuge at all so any addition will be helpful I was just hoping something new was out.
How much sand? 36x18x
How much Cheato?
The display has 4" of sand that I was hoping to slowly reduce to about 1".
I think I should siphon the sand from the bottom slowly. Can I clean and reuse the sand?

[icereefer]

As for sand in your fuge, it depends on how big of a clean up crew you plan of having in your fuge, Cheato is a free floating type macro so no sand is needed, most use sand for rooting macro or extra buffer.
as for Cheato to start out with a hand full is all you need it grows pretty fast.
and if you deside to go with a shallower SB I would suggest you take small amounts out at a time so your don't putting to much of a load on your ecosystem.

[Mako8500]

OUTCH!!!!!!!!my brain hurts ,,,,so your saying take the 1 lb cheito out of main tank because its realy not doing anything but feeding the tangs?

[chineseknife]

No, it is doing something, but it's limited.