Why is a refugium necessary with corals?

[fishdaddy911]

I am considering a refugium for my biocube 32 for hair algae control, I seem to be in the ugly stage pretty deep right now. Last tested, my phosphates were at .15 ppm and nitrates around 6 ppm.

I have only one fish so far, so am supplementing ammonium bicarbonate daily. If I don't, then nitrates will quickly drop to zero and my corals shrivel up.

I understand that refugium with macro algae are a reliable method to remove phos and nitrate from your system. But in a small tank (32 gallons) with corals, does it have any benefit that the corals cannot accomplish?
Since the corals use NO3 and PO4 for growth and remove it from the water, in my small-tank, low-fish situation wouldn't growing additional algea compete/starve my coral?

I don't yet understand what the optimal balance of nutrients is that will benefit my coral, but not benefit hair algae.

 

[fishdaddy911]

Is the nutrient absorption rates between macro-algae, micro-algae, and corals different or significant in some way im not seeing?

 

[NanoSteam]

I am considering a refugium for my biocube 32 for hair algae control, I seem to be in the ugly stage pretty deep right now. Last tested, my phosphates were at .15 ppm and nitrates around 6 ppm.

I have only one fish so far, so am supplementing ammonium bicarbonate daily. If I don't, then nitrates will quickly drop to zero and my corals shrivel up.

I understand that refugium with macro algae are a reliable method to remove phos and nitrate from your system. But in a small tank (32 gallons) with corals, does it have any benefit that the corals cannot accomplish?
Since the corals use NO3 and PO4 for growth and remove it from the water, in my small-tank, low-fish situation wouldn't growing additional algea compete/starve my coral?

I don't yet understand what the optimal balance of nutrients is that will benefit my coral, but not benefit hair algae.

Sounds like you're already struggling with keeping nitrates up so although reducing nitrates is one of the primary goals of a refugium, it also provides a safe haven for beneficial micro organisms to grow that provide food for the corals and fish. All this being said it's most certainly not a requirement especially in a smaller tank. I've only ever kept a refugium once and honestly it was more upkeep then it was worth it for me but others will swear by it.

 

[Mr. Mojo Rising]

I only keep nano tanks (40 gallons and less) and have never had a refugium in almost 20 years of saltwater keeping. IME there is no need on small tanks, regular water changes can replace most filtration systems on a small tank. 3 of my current tanks have zero filtration, only weekly water changes. IMO adding a refugium is unnecessarily making things more complicated. Just me opinion

 

[skey44]

The hope would be the refugium would outcompete the hair algae for nutrients. If you have hair algae growth and testing zeros on nitrates then first I would second guess the testing or acknowledge there is a nutrient surplus feeding the algae but rate the algae is consuming the nitrates the water column is void of nitrates on testing there’s very likely excess N in your system, just not testing for it because it’s become bound in algae.
What test are you using for nitrates? How old is your tank? What kind of rock did you use? Have any pics?
Having a refugium and dosing ammonia are somewhat contradictory. Unless your having to dose ammonia as only a short term solution.

 

[Sumbub]

How long is the tank been up? Maybe you need time for things to balance. If your nitrates are bottoming out but no phosphate movement you might consider a small nitrate dosage to keep it up until the balance in your tank comes along.

 

[skey44]

Also maybe just add a turbo snail instead of. A refugium! They mow down hair algae IME.
I agree tank may need time to balance and dosing some form of N to help achieve balance is potentially necessary. But it’s hard to advise dosing nutrients when you’re having a HA growth. At same time HA is least of my worries when it comes to uglies. CUC easily takes care of it in my tank.

 

[fishdaddy911]

What test are you using for nitrates? How old is your tank? What kind of rock did you use?

Testing nutrients with hanna phosphorus ulr & nitrate hr.
Tank cycle was completed around end of september, so almost three months old.
Most of the rocks were once “live” but I picked up everything secondhand. The previous owner’s heater malfunctioned and killed everything, then they allowed the rocks to dry out. I cycled by adding rocks that were still live to seed the rest of the tank.

There is correlation between the appearance of my coral and the ppm count of the tester. When tester says nitrates are very low, then coral are deflated and sad.

 

[fishdaddy911]

CUC easily takes care of it in my tank.

I have a starry blenny in medicated quarantine, but its still too early to add him now.

 

[Mr. Mojo Rising]

A 3 month old tank is now entering the "ugly stages", what you are facing is very normal and no need for extreme's like adding a refugium at this point. For the next few months you will struggle with algae as the good and bad bacteria fight for dominance. Just try to understand what's happening during the maturing process in your tank and continue with water changes and good maintenance and control nutrients and add cuc and you'll ride it out smoothly. IMO

 

[Sumbub]

Your tank is still in its newish phase. And with liverock it takes a while for it to fully seed. Especially if it’s been cooked. It could be still releasing its nutrients and your nitrates could be getting pulled into the GHA. You just might have to get CUC and let it try and dominate it while doing some manual cleaning til it balances.

 

[twentyleagues]

Refugiums are not needed in any tank. I like them and the various macro algaes available to grow. I mostly think of it as a second saltwater planted tank with some benefits. Mostly a place to grow and keep stuff like pods safe, but there is also the benefit of nutrient absorption. There are possible down sides to keeping macro algae in refugiums on tanks with corals as macros release doc and its thought docs are not beneficial or possibly even harmful to corals. True or not I dont know for sure, I have always had fuges when space allowed and my corals seem to grow fine.

 

[fishdaddy911]

Your tank is still in its newish phase. And with liverock it takes a while for it to fully seed. Especially if it’s been cooked. It could be still releasing its nutrients and your nitrates could be getting pulled into the GHA. You just might have to get CUC and let it try and dominate it while doing some manual cleaning til it balances.

I have only one fish so far, so am supplementing ammonium bicarbonate daily. If I don't, then nitrates will quickly drop to zero and my corals shrivel up.

Is gha capable of absorbing nutrients locked inside of the rock itself?
Wouldn't nutrients being released from the rock show up on my water tests? Like I said, if I don't add ammonium bicarbonate daily then my nitrates become undetectable and my corals look sad.

 

[twentyleagues]

Is gha capable of absorbing nutrients locked inside of the rock itself?
Wouldn't nutrients being released from the rock show up on my water tests? Like I said, if I don't add ammonium bicarbonate daily then my nitrates become undetectable and my corals look sad.

GHA needs predators you, snails, fish, crabs whatever. Be proactive and take it out by hand. If you can grow corals you can grow algaes. I have had reefs in the 50ppm n and 2.0 phosphate range no real algae issues I had stuff that ate it. Its not the nutrients in the water or rock its lack of predators.

 

[Jasonak]

I am considering a refugium for my biocube 32 for hair algae control, I seem to be in the ugly stage pretty deep right now. Last tested, my phosphates were at .15 ppm and nitrates around 6 ppm.

I have only one fish so far, so am supplementing ammonium bicarbonate daily. If I don't, then nitrates will quickly drop to zero and my corals shrivel up.

I understand that refugium with macro algae are a reliable method to remove phos and nitrate from your system. But in a small tank (32 gallons) with corals, does it have any benefit that the corals cannot accomplish?
Since the corals use NO3 and PO4 for growth and remove it from the water, in my small-tank, low-fish situation wouldn't growing additional algea compete/starve my coral?

I don't yet understand what the optimal balance of nutrients is that will benefit my coral, but not benefit hair algae.

If your dosing nitrates to keep them up you dont need a fuge.
Trying cutting back your light period to help with hair algae and as others have said snails.

 

[Sumbub]

GHA can absorb from the water column. It could be the reason the nitrates disappear from your constant testing because it's uptaking it really fast. Reducing its footprint could slow the down nitrate uptake from the water column.

As for the nutrients in the liverock, it slowly releases into the water column. But tbh, I can't say if it can absorb it from deep inside the rock.

 

[exnisstech]

I know people run macro algae fuges to help with lowering N and P. TBH I've never had it help with that. I've run large fuges with a ball of chaeto the size of a basket ball down to mini fuges in smaller tanks. The only thing I've found them useful for IME is providing a place for little creatures to live and reproduce without predation.

 

[daikaijureefer]

I have the same tank as you and am 3 months in. I’ve tried to set up chaetomorpha on the back side of the tank as a refugium twice, and both times the chaeto turned to mush and was getting sucked into my return pump. I have a chaetomax light on the back, for reference.

I am also using the intank media tower on the back wall and a small tunze skimmer.

I don’t know if this might interest you, but since I already had the light on the back, what I did decide to go with is a make-shift turf scrubber for hair algae out of a single craft sheet and placed it below my skimmer in a concave shape away from the light. Pic three you can see hair algae growth after four days:









I may try chaeto again in the future. I’ve had it in larger systems in the past and loved it. I’ve also heard anecdotally that it doesn’t do well in too new of a system, which I can kind of understand as a lot of biomes are forming and trying to outcompete each other quickly.

That’s why a GHA turf scrubber seemed like a safe bet for me until I have a more established system. But I may remove the turf scrubber too. My hope was that it would even out ph swings at night on a reverse light cycle, but I’m not sure if there’s enough GHA for it to have much of an effect to accomplish that.

 

[daikaijureefer]

Oh, and you can see that I put some rubble in the media tower for pods, so this adds to the “refuge” aspect of the refugium. I imagine pods will like the craft sheet covered in GHA as well.

 

[daikaijureefer]

I should have also said, to answer your original question, that I don’t think it’s necessary, and may have little effect on our smaller tanks, making it more trouble than it’s worth. Corals certainly don’t “need” a refugium by any means.

I can tell you now that I have two part dosing lines, an ATO, water change lines, a skimmer, custom lighting cables all running through the lid, and I really hate lifting it up when I don’t have to. Complicating it further with the skimmer in the way of the algae scrubber makes it even less desirable to do maintenance to. Which is why I may just do away with it and use just the media tower and skimmer.

One thing I also did not account for but, (duh) film algae has built up on the back glass where the chateomax light is attached and it requires scraping otherwise the turf scrubber doesn’t get full light. And if you thought scraping algae on your front glass was a pain… haha. The more I type this the more I want to just turn the light off and take it out, lol. So keep that in mind. Most folks are running a refugium in a standalone sump with a light overhead, which isn’t really the case for our setup.

I think if I had dedicated the entire back wall to a refugium instead of having a media tower and skimmer, and filled it with chaeto, then maybe it would have a much larger effect. For a KISS method setup, that may be ideal.

But for me, I can’t see myself getting rid of the media tower and skimmer anytime soon. I’ve gone a bit high tech and my skimmer is also set up with a CO2 scrubber, which DOES have a very measurable and positive effect to my pH.