From a Hydroponic standpoint, does refugium size matter?

[Fritzhamer]

As I was endlessly tinkering under the tank this week and contemplating all the sump changes I could make, I started thinking about another project I'm working on. The other project is a hydroponic setup using fish to add nutrients to the water that the plants will take up. Our refugiums are really the same concept, just without roots as the means of gathering nutrients.

It seems to me that the limiting factor for our refugiums is (surface area) exposure to light. In a narrow fuge I can grow more cheato if it tumbles. Without tumbling I need a fuge with more surface area as the deeper cheato will be shaded by the light drenched cheato at the top.

In my fuge I run a mix of about every algae I could get my hands on. I regularly mix it up and stir it around. Still though I have the issue of deeper shaded algae not thriving the way the light drenched algae does. A larger fuge (deeper) would do very little, to me it seems, in allowing me to grow more algae. If anything I think that a submerged light would be more beneficial given any space constraints.

In order to grow more algae mass I'd need a larger surface area and possibly more light. Maybe measuring fuges in gallons is a pointless endeavor as length and width (plus flow) are likely far more meaningful than depth + flow. Has anyone tried a submerged light? I run about 10% of my volume as fuge and its pretty shallow. I don't find space to be a limiting factor for me but I think the 10% vs 20% vs 5% to be an irrelevant conversation by this theory. It should just come down to flow plus surface area as I understand it.

Thoughts?

 

[rkpetersen]

Isn't that what's basically happening in an algae reactor? Creating more efficient illumination than you would get with most regular sump setups with overhanging light.

So I would guess that a properly designed submerged light would be a fantastic addition.

Also you don't necessarily have to have your chaeto roll to get fantastic growth, if you're willing to turn the mat over manually every day or two.

 

[davocean]

I agree, op basically described an ATS

 

[Fritzhamer]

I’m not though. In my ten gallon fuge I have an algae mass that would fill a five gallon fish tank submerged. This is after trimming back. In order to run a reactor I’d need a ten gallon bucket which just isn’t as practical to me as my fuge is.

My point is that our 10-20% fuge volume is as irrelevant a number as “how many watts per gallon do I need for sps?”. If my fuge were four inches wide but the same volume I wouldn’t be able to sustain the same algae mass.

Having a shallow fuge with a large surface area would sustain a larger mass. If the goal is to maximize the effectiveness of the algae mass, large surface area would be better. Yes reactors are effective but this has more to do with thinking of a fuge in hydroponic terms, how do we get the most growth possible.

If I were farming cheato, culverts, etc. I’d probably grow it on sheets with the water an inch deep or so to maximize growth. Having a ten inch deep fuge that was 12x6 just isn’t the same in terms of possible output. Even with a submerged light.

 

[rushbattle]

It’s just algal surface area receiving enough photons to photosynthesize. A chaeto ball spinning effectively increases surface area because it’s rotating and exposing all the surface area to light. So surface area of fuge is just a proxy for surface area of algae lit well enough to grow in its current environment.

 

[rishma]

I’m not though. In my ten gallon fuge I have an algae mass that would fill a five gallon fish tank submerged. This is after trimming back. In order to run a reactor I’d need a ten gallon bucket which just isn’t as practical to me as my fuge is.

My point is that our 10-20% fuge volume is as irrelevant a number as “how many watts per gallon do I need for sps?”. If my fuge were four inches wide but the same volume I wouldn’t be able to sustain the same algae mass.

Having a shallow fuge with a large surface area would sustain a larger mass. If the goal is to maximize the effectiveness of the algae mass, large surface area would be better. Yes reactors are effective but this has more to do with thinking of a fuge in hydroponic terms, how do we get the most growth possible.

If I were farming cheato, culverts, etc. I’d probably grow it on sheets with the water an inch deep or so to maximize growth. Having a ten inch deep fuge that was 12x6 just isn’t the same in terms of possible output. Even with a submerged light.

Technically you are right. The volume doesn’t matter much (Of the display Or refugium). But it’s a fair proxy just like Watts per gallon was fair when we all used the same kind of lights. Not exact or accurate but helpful. There are tons of real variables like Surface area, algae mass, pur/par, nutrient concentrations, flow rates, many more. No doubt it’s complicated. I think it’s much easier for people to target around 10 or 20% of their tank volume rather than get to target all the many variables. I’m sure we’ll evolve on this subject over time.

 

[fermentedhiker]

I think your conflating two related but not necessarily identical things. Fuges aren't all cheato(or whatever free floating macro you fancy) grow chambers. A refugium can lots of things from remote DSB, filter feeder areas, cryptic areas, mangroves, and yes macros, and often it is more than one. I suspect that classic volume compared to display was as much a practical matter more than a verifiable ideal. The actual dimensions of a fuge area are often limited by the size of the stand, other equipment in the sump, and layout. At the end of the day a guideline is a place to start not the ultimate answer for anything.

Also the issue of shading in a deeper area for macro algae can be overcome with a more powerful light. HPS or high powered LEDs can easily penetrate through a mass of chaeto and keep the stuff on the bottom green and happy.

 

[Fritzhamer]

I hear ya. I technically have several refugiums; my overflow is covered with rigid black acrylic making it a cryptic zone. There is no doubt lots of life in there. Perhaps fuge was the wrong term for this post but I was thinking of it in terms of the Triton method and as a means of nutrient export.

I get the space constraints of under the stand management point. My favorite posts are people showing how much they’ve packed under their stand. Most of my tank tinkering is me trying to find more efficient layouts for under my tank.

The line of thinking in the post has had me rethinking how my fuge and sump was planned. In my experience just using a brighter light doesn’t work. Just like in the display, if I’m getting 500 par on the sand I’m probably getting 1500 par near the top. None of my algaes have appreacited super bright light, they would ultimately bleach even when slowly acclimating to the stronger light. The limiting factor wasn’t par but perhaps available nutrients or maybe there was just too much light.

Again thinking in terms of maximizing growth, if that’s what we’re looking to do, maybe we’re thinking of these algae grow chambers in the wrong way. Maybe the design we should be evolving to is wide, long and shallow.

 

[fermentedhiker]

I hear ya. I technically have several refugiums; my overflow is covered with rigid black acrylic making it a cryptic zone. There is no doubt lots of life in there. Perhaps fuge was the wrong term for this post but I was thinking of it in terms of the Triton method and as a means of nutrient export.

I get the space constraints of under the stand management point. My favorite posts are people showing how much they’ve packed under their stand. Most of my tank tinkering is me trying to find more efficient layouts for under my tank.

The line of thinking in the post has had me rethinking how my fuge and sump was planned. In my experience just using a brighter light doesn’t work. Just like in the display, if I’m getting 500 par on the sand I’m probably getting 1500 par near the top. None of my algaes have appreacited super bright light, they would ultimately bleach even when slowly acclimating to the stronger light. The limiting factor wasn’t par but perhaps available nutrients or maybe there was just too much light.

Again thinking in terms of maximizing growth, if that’s what we’re looking to do, maybe we’re thinking of these algae grow chambers in the wrong way. Maybe the design we should be evolving to is wide, long and shallow.

From a maximizing growth from chaeto or something similar is you goal. I think one of the earlier posts about chaeto reactors address the issue. By lighting the reactor tube all the way around they ensure even par without tumbling in a relatively small area. Assuming you can fit one under the stand this would free up the chaeto fuge in the sump for something else. Not Triton but a modified version.

 

[Fritzhamer]

From a maximizing growth from chaeto or something similar is you goal. I think one of the earlier posts about chaeto reactors address the issue. By lighting the reactor tube all the way around they ensure even par without tumbling in a relatively small area. Assuming you can fit one under the stand this would free up the chaeto fuge in the sump for something else. Not Triton but a modified version.

For sure you can maximie growth in a reactor but this isn’t a large scale endeavor. My algae mass is about the size of a volleyball after trimming it back. A reactor, for me isn’t as efficient a production method for my scale. I understand that people get great results and it seems a super efficient means of growing small scale algae growth farms. A friend of mine ran one twelve years ago or so in a shipping barrel for his 120. That was a cool setup that probably most people won’t be able to reproduce.

Even if I were to run a reactor in a five gallon bucket it would be a lateral move for me. It would also take up more space. What would be ideal would be to find some use for the space under a fuge in our sumps. Perhaps a DSB. If only the first four or so inches of the fuge have any value and most of us have deeper and taller fuge areas...

I’d love to see a sump design that had a second story with a large and shallow fuge “pan”. They way we used drip plates way back in the day. Some six inch deep (perhaps) area where macro algae can be farmed which would then overflow out to another chamber.

 

[fish farmer]

I’d love to see a sump design that had a second story with a large and shallow fuge “pan”. They way we used drip plates way back in the day. Some six inch deep (perhaps) area where macro algae can be farmed which would then overflow out to another chamber.

Interesing thought. Much like a raceway used in trout production. If you run a deep raceway with x amount of flow, wastes tend to build up quicker. Run a shallower raceway, you have better turnover with the same amount of flow. Lighting options, instead of strong narrow point lighting, you could run strip lighting. You could even add baffles to the design and possibly get a tumble.

Although I recently modded the flow through my refuge area which would be considered "deep" and all my cheato it now up against the wall. Perhaps by adding upright rods along the pan would keep the chaeto in place.

 

[fermentedhiker]

I think that has been done by some, although perhaps not for the same reasons/goals etc... I used to see when I was researching cryptic fuges some people had setup something they called hybrid or combo or something like that fuges. Some had DSB underneath the cheato and some created eggcrate platforms with cheato on top and rubble underneath. Not sure how successful they were.

 

[garbled]

On one of my fuges I have an LED basically strapped to the side near the bottom lighting the algae up from underneath. I've been thinking for my next fuge, which will be really deep, to wrap the bottom 3-4 inches in red led string lights like people use for DIY algea reactors.

 

[Fritzhamer]

On one of my fuges I have an LED basically strapped to the side near the bottom lighting the algae up from underneath. I've been thinking for my next fuge, which will be really deep, to wrap the bottom 3-4 inches in red led string lights like people use for DIY algea reactors.

That’s really interesting. That’s a great idea! I think I might remove the rubble from the bottom of my fuge and place led strips underneath lighting from the bottom up.