Help me understand how a refugium outcompetes other algae

[TheGrimReeferTx]

Hello reefing family. I am unable to wrap my head around how a refugium or algae scrubber "out-competes" other algae. Let me explain.

For ease of understanding let's make complex life simpler. Algae needs 3 things to grow carbon, phosphate, and nitrate. To assist with the nusances algae in my tank I add a refugium and run it 16 hours a day. In doing this the refugium is a great competitor for nutrients in the aquarium. But I try to keep a balance in my aquarium, I have decided I need a certain level of nutrients in the water. As I notice decreases in phosphate and nitrate I dose them back to the desired level.

Since none of these amounts are hitting zero and starving out other algae how then is my refugium or algae scrubber out-competing anything? I have been racking my brain for days. What am I missing?

 

[lapin]

As you said it competes for nutrients. If it’s too large it will consume too much.
Not sure at what level you are keeping nutrients at. Might be time to prune it back a bit to create a better balance.

 

[Silly clownfish]

I’ve asked myself a similar question. I struggle to keep “good” algae alive in my fuge, but often have one or more types of algae I don’t want in the display- at least in some areas.

 

[Garf]

Hello reefing family. I am unable to wrap my head around how a refugium or algae scrubber "out-competes" other algae. Let me explain.

For ease of understanding let's make complex life simpler. Algae needs 3 things to grow carbon, phosphate, and nitrate. To assist with the nusances algae in my tank I add a refugium and run it 16 hours a day. In doing this the refugium is a great competitor for nutrients in the aquarium. But I try to keep a balance in my aquarium, I have decided I need a certain level of nutrients in the water. As I notice decreases in phosphate and nitrate I dose them back to the desired level.

Since none of these amounts are hitting zero and starving out other algae how then is my refugium or algae scrubber out-competing anything? I have been racking my brain for days. What am I missing?

It works through a mechanism of magic and wishful thinking.

 

[Miami Reef]

If the algae in the refugium or scrubber can deplete nutrients or trace elements, then it is theoretically possible for the algae in the display and reactor to become limited and not continue grow.

Realistically, we input food daily which supplies both nutrients and trace elements. Most people would opt to dose nutrients if the NO3 or PO4 get too low, so I don’t think it’s a probable expectation.

Algae needs very little detectable nutrients and trace elements to grow.

 

[larreef]

A refugium doesn’t do anything.


It’s other algaes/micro flora/ etc that can outcompete nuisance algaes in a BALANCED tank.

 

[Cthulukelele]

I think most people describing it as "outcompeting" other algae are using shorthand. It's a form of nutrient export taking away C, N, and P that would have otherwise remained in the water column. If someone's nutrients are bottoming out and they're dosing nitrate and phosphate and still have a DT algae problem it likely isn't going to help, but it's there as a tool to lower nitrates/phosphates to a lesser extent.

 

[VintageReefer]

A turf scrubber will severely limit the growth of display algae. A refugium could do the same but most fuges are undersized to handle this task alone.

Turf algae grows faster than other types and absorbs 5-10x the amount of phosphates compared to an equal amount of cheato.

Scrubbers consume excess from the water, limiting the amount leftover for other algae to use. My scrubber is a 4x2x2 box with 1000 par of red 660nm led lighting, less than an inch from the algae, in the spectrum that grows algae best. It’s an ideal environment for algae, and it grows much easier than the display

 

[TheGrimReeferTx]

I think most people describing it as "outcompeting" other algae are using shorthand. It's a form of nutrient export taking away C, N, and P that would have otherwise remained in the water column. If someone's nutrients are bottoming out and they're dosing nitrate and phosphate and still have a DT algae problem it likely isn't going to help, but it's there as a tool to lower nitrates/phosphates to a lesser extent.

That has been my understanding. I just couldn't wrap my head around the "outcompeting" it can only do so if using all of something that isn't allowing other algae to grow. That being said, I appreciate everyone's responses here. I knew it wasn't as magical as some made it sound!

 

[Reefering1]

The problem with starving the algea away is that you might also be starving the corals too. As said above, they are just 2 of the many tools to export nutrients(and fuges have additional benefits).

 

[VintageReefer]

That has been my understanding. I just couldn't wrap my head around the "outcompeting" it can only do so if using all of something that isn't allowing other algae to grow. That being said, I appreciate everyone's responses here. I knew it wasn't as magical as some made it sound!

You can believe what you want…but I will tell you, my scrubber killed all my cheato (basketball size amount, growing healthy pre scrubber). And a scrubber is the only method of nutrient management and control I use on my tank, and this tank has been running 4 years with no water changes, I stopped using a skimmer about 1.5 years ago with no negative effects. I don’t use carbon or vodka or gfo or anything. My scrubber is my only filtration. I only add top off water with all for reef 2x a week. Top off + glass cleaning is my only maintenance


My scrubber is dialed in for my system, my nitrates are always 0-2, phosphate always 0-.02

You would say by the numbers my corals are starving. Wrong. Everything uses the same water. It’s a free for all for nutrients. My corals take what they need. My scrubber aggressively takes what it needs. There is very little leftover for pest algae, but it does exists. And the free amount in the water is near zero, but that’s after everything already gets what it needs.

Non existent of my corals are starving. I’ve grown all this out over the last 1, 2, 3, or 4 years depending on the piece.

Do I have algae in the display? Yes. But very little and it’s managed and under control.

 

[VintageReefer]

That has been my understanding. I just couldn't wrap my head around the "outcompeting" it can only do so if using all of something that isn't allowing other algae to grow. That being said, I appreciate everyone's responses here. I knew it wasn't as magical as some made it sound!

Maybe instead of outcompeting you could say “limiting” or “reducing”

 

[RocketEngineer]

Ok, there’s a big piece missing from this discussion: algae eaters. In the display, you have a bunch of critters eating algae. In the refugium these algae eaters are absent. Therefore the algae in the display is being eaten while also competing for nutrients with the refugium, which typically runs in the reverse daylight cycle. It’s the algae eaters that tip the scale.

 

[Garf]

I found this quote on the Fauna Marin site recently, which tickled me
"As algae release further growth-inhibiting substances and are also in competition with corals, we do not recommend refugia if stony corals are to be kept. Higher algae are rarely found in a reef. Their preferred habitat are other zones of the coastal areas."

Iodine - Fauna Marin

www.faunamarin.de

 

[VintageReefer]

It’s a nitrate and phosphate control method just like any other. And it’s a very efficient one. I got tired of changing phosphate media every 2-3 days. I never was a fan of water changes. Cheato grew very well for me, but didn’t make the impact I needed in any way.

Here was my cheato fuge


I sold multiple bags like this, every weekend. I’d sell them to local reefers and I sold them online. So. Growing cheato was not the problem. I had a healthy cheato system.

I added the scrubber and in a month the scrubber established its own turf algae colony. The next month this healthy cheato started to go pale, and it all died. The next month in my display tank hair algae started growing everywhere. Out of random spots in the sand. Out of the rocks. All over.

The scrubber was stripping phosphate from the water and phosphate was unbinding from the rocks and sand to create equilibrium. That term “phosphate bound rock”. Yea. I had that. And scrubbers properly sized can fix it. And that’s what I was witnessing.

And then…the new display algae...it started turning pale, then white, then it was wispy and could be pulled off easily. The cycle repeated itself once more. And then. It stopped. The hair algae is been battling in my display for years, was gone. And it didn’t come back.

My rocks and sand were cleaned of excess bound phosphates and the fuel for algae was being consumed by my scrubber

Then I started losing sps. I was over scrubbing. You want to be aggressive when getting a situation under control but then you need to dial back the hours to not over strip. I reduced by one hour a week, for two weeks, and found 18 hours a day was what I needed to keep my system in check

 

[VintageReefer]

Ok, there’s a big piece missing from this discussion: algae eaters. In the display, you have a bunch of critters eating algae. In the refugium these algae eaters are absent. Therefore the algae in the display is being eaten while also competing for nutrients with the refugium, which typically runs in the reverse daylight cycle. It’s the algae eaters that tip the scale.

They are a part - and they can be what tips the scale, or they can be a small part

Some people buy massive cleaning creas and tip the scale that way. Sure, 100 snails and hermits in a 75g tank can tip the scale in your favor. But when they run out they will die off and cause more algae. And they don’t touch the long stuff

In my 75g display I have 4-5 turbos and 5 scarlet hermits, maybe 3 bumblebee snails. And to keep sand stirred 5 nassarius and 1 conch

The critters are not tipping the scale for me, they are handling the little bit that grows that my scrubber allows. I have dialed back up and run more aggressive to attempt to get 100% control of display algae but my corals began to pale. So I wen back to my 18 hours and enjoy 95% algae free display

 

[Miami Reef]

I found this quote on the Fauna Marin site recently, which tickled me
"As algae release further growth-inhibiting substances and are also in competition with corals, we do not recommend refugia if stony corals are to be kept. Higher algae are rarely found in a reef. Their preferred habitat are other zones of the coastal areas."

Iodine - Fauna Marin

www.faunamarin.de

Do you actually believe that?

 

[Garf]

Do you actually believe that?

All sorts of algae give off allelopathic compounds and if grown in enough quantity, yes, I believe that, especially in a closed system. However I think most folk don't grow it in enough quantity to outright poison things. Now, if you are talking about algal sugars fuelling algal associated bacteria instead of coral associated bacteria (fuelled by CCA sugars), that's very believable. In fact I spent a couple of years googling algae stuff 12 or so years ago when I was an ATS fanatic and Fauna Marins summary brought back memories of the conclusions I made.

 

[Spare time]

Algae is limited by predation in a reef tank. Sure competition plays a partin terms of real estate in some aspects, but the whole point of a reef tank is to grow algae (zooxanthellae), which means a proper reef tank should have enough available nitrogen and phosphate to grow algae. It is simply false that a refugium or scrubber is preventing algae from growing in the display based off of the logic related to a reef tank having enough available nitrogen and phosphate to grow zooxanthellae.

 

[VintageReefer]