Refugium size and nutrient export

[PDR]

I have been reading a lot about refugiums and what I have failed to learn is how a larger refugium increases nutrient export.

For this example lets assume chaeto is being used for nutrient export and one fuge is 12x12x12 and the other is 24x24x12 (almost 4x the volume).

What about the larger fuge would increase nutrient export? The amount of chaeto that can grow? Does a larger amount of chaeto grow faster/remove more nutrients or does it grow at the same rate regardless of the size of the chaeto ball? Is it related to turnover?

Can someone help me understand this?

Thanks!

 

[OriginalUserName]

IMO the main limiting factor on most fuges is the amount of light. Bigger fuge does let you have more chaeto but if it isn't lit properly it's not going to add much.

Check out the brs tests on fuges/lights

 

[PDR]

IMO the main limiting factor on most fuges is the amount of light. Bigger fuge does let you have more chaeto but if it isn't lit properly it's not going to add much.

Check out the brs tests on fuges/lights

Thanks for the reply. I totally agree that lighting is the most important aspect of having a successful fuge. I have watched all the BRS videos.

It seems that it is common advice that a fuge must be x% of your display volume in order to be effective. My main question is why?

If I had a 75 gallon tank with a 10 gallon fuge, how would a 30 gallon fuge increase nutrient export assuming light and flow were the same?

 

[Skep18]

I suspect if 1 ball of chaeto can grow "X" per month then 2 balls of the same size/weight can grow "2X" per month. Each piece of plant can grow. If there is more plant, there would be more growth.

As per above, this is all predicated on one much have sufficient light, flow, nutrients, etc. to permit this growth.

 

[PDR]

I suspect if 1 ball of chaeto can grow "X" per month then 2 balls of the same size/weight can grow "2X" per month. Each piece of plant can grow. If there is more plant, there would be more growth.

That's the only thing I can think that would make a difference. What's confusing to me is it seems to be common practice to remove large portions of chaeto at a time (basketball size reduced to baseball size for example). If more chaeto is the key, wouldn't it be best to keep as much chaeto in the fuge as possible at all times? Wouldn't removing that much greatly decrease the effectiveness of the fuge?

 

[OriginalUserName]

That's the only thing I can think that would make a difference. What's confusing to me is it seems to be common practice to remove large portions of chaeto at a time (basketball size reduced to baseball size for example). If more chaeto is the key, wouldn't it be best to keep as much chaeto in the fuge as possible at all times? Wouldn't removing that much greatly decrease the effectiveness of the fuge?

It's a balancing act. If you never remove it then you aren't exporting many nutrients, if you remove too much, then you are limiting yourself because it can only grow so fast. On my small cube fuge I have settled on more or less removing 30% of the chaeto when it gets to the point where there isn't a ton of room and where presumably I'm starting to get some die off because it's shading itself and limiting flow.

 

[HolisticBear]

What's confusing to me is it seems to be common practice to remove large portions of chaeto at a time (basketball size reduced to baseball size for example)

Triton advocates for letting your fuge naturally break down, yet in my mind the risk vs reward with a fuge is very clearly on the side on ensuring your fuge is healthy and has room to grow. On one side, if you over trim, you may get less than maximal nutrient export (sort of minor), yet if your fuge completely dies and dumps all that into your tank, you tank will be wrecked potentially requiring weeks and weeks of work to recover.

Typically your fuge won't suffer a massive die off, but if can happen if nutrients go to zero, you increase lighting and nuke it, or it gets so packed and dense that stuff dies off (this is usually ok, cause small die off). So removing chaeto is an export, but compared to GFO/Carbon export, fuge export is living thing, and it's good to err on the side of caution and keep it healthy.