Does size matter? Refugiums

[F i s h y]

Recently saw on another thread where a fellow reefer made the comment that most aquariums don't have a refugium that is big enough to make any meaning full impact on nutrients. I personally do not agree with that statement but it got me to thinking...

What size is "just right" for a given system and how can we measure to be sure. (Spoiler: I think it will be different for all systems)

I personally have a very large refugium, it is 24 inches by 18 wide by 14 deep. It is completely full of Chaeto and I still struggle with high PO4 and No3 values. I know this is due to my large bio load and the insane amount of food that my fish eat. Total system volume is around 360 gallons with 34 fish.

Video to show fish sizes:





So how big are your refugiums and how efficient are they at controlling your nutrients?

 

[shakacuz]

isn't the general consensus of reef tanks in general that the bigger the tank, the better it is to manage? i would assume it holds true with sumps as well. more water volume = easier reef keeping (generally). for those that do water changes......probably not as much.

i do agree with you not agreeing with their statement. my DT is a 40B, sump is a 20G long. roughly 45g of water volume after accounting for rock/sand displacement.

 

[kvansloo]

The refugium under my 90 gal. tank is 75 gal., as long as you have enough room for the filtration system and every thing you need under there and the refugium does not overfill it should be good. But I have always over sized everything in filtration system.

 

[yury88]

Your refugium can be totally packed with Chaeto and be useless same time.
It's working only if you are dumping part of Chaeto every week, only this way export of nutrition happened.
In my case my Chaeto double its weight every week with 7h light a day.
And I'm dosing Marinium Iron to support it grows
And I don't have skimmer, only refugium and fleece filter, works fine for me, but my lish load is low

 

[F i s h y]

Your refugium can be totally packed with Chaeto and be useless same time.
It's working only if you are dumping part of Chaeto every week, only this way export of nutrition happened.
In my case my Chaeto double its weight every week with 7h light a day.
And I'm dosing Marinium Iron to support it grows
And I don't have skimmer, only refugium and fleece filter, works fine for me, but my lish load is low

Interesting thoughts. I am not sure that i agree that the only way to export the nutrients is to remove part of the Chaeto. The Chaeto uses the No3 and Po4 to grow. the same as we use food. More growth and more Chaeto would to me coincide with a higher level of nutrient export. The export occurs by the growth of the Cheato, not the removal if i understand the basic process correctly.

 

[F i s h y]

isn't the general consensus of reef tanks in general that the bigger the tank, the better it is to manage? i would assume it holds true with sumps as well. more water volume = easier reef keeping (generally). for those that do water changes......probably not as much.

i do agree with you not agreeing with their statement. my DT is a 40B, sump is a 20G long. roughly 45g of water volume after accounting for rock/sand displacement.

Ive always been a bigger is better guy. but i could see the reverse that if youare running a huge refugium you could potentially over strip your system of nutrients.

 

[yury88]

Interesting thoughts. I am not sure that i agree that the only way to export the nutrients is to remove part of the Chaeto. The Chaeto uses the No3 and Po4 to grow. the same as we use food. More growth and more Chaeto would to me coincide with a higher level of nutrient export. The export occurs by the growth of the Cheato, not the removal if i understand the basic process correctly.

After some point it will just stop growing. Because top levels shadowing bottom etc.
You can easily understand how exactly it's working if you will start using weight to check what kind of grown you have.

And realy zero magic here, just decent light, flow and some Iron supplement do the job

 

[darrick001]

I have a 500 gallon display that has a 210 refugium. I run the tank at undetectable levels. There is no skimmer. The coral eat plankton and very little nitrate or phosphate. Coral growth is very good. On the flip side I have a new 110 with a 4 gallon refugium. This system only has 4 fish right now but levels are undetectable with no skimmer. Refugium size really has to do with how much you feed. The more you feed the bigger the skimmer needs to be. Lighting and flow play a big part. 2 refugiums of the same size with differnt lighting and flow will have differnt capabilities.

I try to set my flow and lighting at higher levels than the display.

 

[Spare time]

You can offset a small refugium by having a strong light. It's about growth rate more so than size. A large refugium with a crappy light likely won't perform as well as a smaller one with a strong light.

 

[VintageReefer]

If it was me that made that statement, let me explain

Some of the people with success here:
75g refugium for a 90g tank = larger than average and proper size

500g tank with 210g refugium. This is a huge refugium.

These are both perfectly fine

What I’m talking about is the typical out the box sump from most companies

Here’s two popular brand sumps (I own the trigger)

These sumps have small refugiums around 5 gallons. It’s not enough to control nutrient levels in the size tanks they are made for

Here mine when I used it as a refugium

You can see, I had it packed growing cheato. I harvested weekly and sold it online each week. Here’s two bags I sold

So yea I was harvesting and growing just fine. Did this for over a year. It has zero impact on my tanks algae issues. Maybe it was keeping them from getting worse. But it wasn’t controlling and correcting my issues

 

[VintageReefer]

I stepped up to an algae scrubber. Freed up over half the space in this chamber.
What happened next…
Over the course of a month the scrubber became established. Over the next month all my cheato became pale and died off. Cheato that was growing just fine for over a year never having an issue

Over the next month I had hair algae growing out of the most random of places in my display. Right out kf the sand bed. Out of the live rock. Out of bases of plugs. Out of dead spots on corals where skeleton was exposed. And then. All this random hair algae started to turn pale and weak and it died. And it would come back a few days later and turn pale and disappear a few days later.

And then…the algae was gone from the display and it didn’t come back.

Scrubbers are more efficient than cheato. It’s simply that turf algae is a better form of algae for absorbing phosphate and nitrate compared to cheato. Turf holds 5-10x the amount of nutrients compared to an equal amount of cheato. And it grows faster. Can refugiums work ? Absolutely. It’s the same concept. They just need to be larger.

My original comment was talking about sumps like mine with built in refugium compartments. 5g refugium for 80-100g of water volume? Not big enough. 50-60g refugium for 80-100g tank? Yea now we are talking about potential for success

 

[VintageReefer]

personally have a very large refugium, it is 24 inches by 18 wide by 14 deep. It is completely full of Chaeto and I still struggle with high PO4 and No3 values. I know this is due to my large bio load and the insane amount of food that my fish eat. Total system volume is around 360 gallons with 34 fish.

By my calculations your fuge is approx 26 gallons assuming it’s filled to the top. And your tank is 360g and heavily stocked

The people with success above have fuges around 50% or greater compared to display volume. And you state you struggle with nitrate and phosphate despite the large fuge. From my perspective, its undersized. Don’t get me wrong. I am sure things would be worse without it. But it simply isn’t large enough to do 100% nutrient control.

If the fuge was 150 gallons or more…just imagine. I am sure that would make a significant improvement

Anyway that is what I meant by my statement. Most people can not run a fuge large enough for 100% control and most out the box sumps are drastically undersized with refugiums built in.

 

[darrick001]

I don't think sump manufacturers design with the thought of is this refugium the correct size for the intended tank. I think they stay with the thinking that it's not necessary. It's an after thought. Most people want options when they buy their sump. Some may have no idea what they want or really need for their setup. So they build the sump to accommodate a huge skimmer filter socks, ect, and whatever is left over is the refugium. I do believe they are trying to give every option in the smallest pkg. Some are installing all their other products into the sump. It's a great business move but not necessarily the best for advancing the hobby.

 

[Bruttall]

300g dt, 125g DIY Sump, the "fuge" chamber is 14 x 18 and holds about 14inches of water. Approx 15g of water. I can't grow Chaeto, it just withers and dies, so I grow what ever algae will grow in there under light opposite the tank lights. I do not have a ton of algae in my display but I have 7 tangs so they keep it pretty well under control. System is just over 1 yr old.

 

[F i s h y]

By my calculations your fuge is approx 26 gallons assuming it’s filled to the top. And your tank is 360g and heavily stocked

The people with success above have fuges around 50% or greater compared to display volume. And you state you struggle with nitrate and phosphate despite the large fuge. From my perspective, its undersized. Don’t get me wrong. I am sure things would be worse without it. But it simply isn’t large enough to do 100% nutrient control.

If the fuge was 150 gallons or more…just imagine. I am sure that would make a significant improvement

Anyway that is what I meant by my statement. Most people can not run a fuge large enough for 100% control and most out the box sumps are drastically undersized with refugiums built in.

Appreciate the responses and the thoughts. I dont remember if it was you that originally said it or not. I also would agree with much of what you said.

There are so many variables that contribute to the answer. My refugium was great... until I added so many xl fish. Now it just doesn’t do an adequate job.

 

[Bruttall]

Appreciate the responses and the thoughts. I dont remember if it was you that originally said it or not. I also would agree with much of what you said.

There are so many variables that contribute to the answer. My refugium was great... until I added so many xl fish. Now it just doesn’t do an adequate job.

have you tried to increase duration of light on fuge?

 

[F i s h y]

have you tried to increase duration of light on fuge?

I actually just did this on Tuesday so waiting to see what the results are. Will be testing today.

 

[VintageReefer]

I don't think sump manufacturers design with the thought of is this refugium the correct size for the intended tank

Agreed. And I meant overall they design a sump that holds x amount of gallons and recommend it for tanks of a certain size range. And they are correct, overall the sump is designed for those tanks. And some have small refugiums. Which is great as a spot for copepods and some macro, but it’s not designed to be a fuge capable of filtering the entire connected tank. It’s a safe spot for pods and micro critters.

300g dt, 125g DIY Sump, the "fuge" chamber is 14 x 18 and holds about 14inches of water. Approx 15g of water. I can't grow Chaeto

your filtration is large and husbandry is top notch. It doesn’t surprise me you have difficulty growing cheato

Appreciate the responses and the thoughts. I dont remember if it was you that originally said it or not

I have made such claims in posts, so I don’t know if it was me or not. If it wasn’t,I think I understand what the other person was saying and why

 

[darrick001]

Agreed. And I meant overall they design a sump that holds x amount of gallons and recommend it for tanks of a certain size range. And they are correct, overall the sump is designed for those tanks. And some have small refugiums. Which is great as a spot for copepods and some macro, but it’s not designed to be a fuge capable of filtering the entire connected tank. It’s a safe spot for pods and micro

100% agree.

 

[Bruttall]

Thanks @VintageReefer