Help between refugium or turf scrubber for my setup

[VintageReefer]

@VintageReefer I assume we're talking about this:

https://www.santa-monica.cc/SURF4x-...tra-light-for-higher-nutrient-water_p_73.html
I'm tempted.

I use a surf2 but there are various size models in the series

 

[VintageReefer]

Whilst you amaze yourself at your latest reefing purchase, and the purple lights, someone lobs a couple of urchins and half a dozen snails in your display.

You know how many people have snails and then get urchins and come back here saying they didn’t help?

 

[VintageReefer]

I’m not getting that either, though I know it is often claimed.

The related claim is that trying to reduce pest algae by reducing nutrients typically fails because corals won’t be happy at the necessarily low levels.

The only way both can be true (if real) is if it’s not nutrients that limit algae in the display but something else like a trace element.

Its not impossible that the algae need something such as iron at a higher level than corals, and a scrubber drives it down.

I’ll let you know when I get my icp results. Mailed out last Thursday

 

[PharmrJohn]

I use a surf2 but there are various size models in the series

Yep. This is on my to buy list. The Surf4 in my case

 

[VintageReefer]

I was reading the instructions and it says you head a hd air pump. Are you running the pump by your tank or remote? My tank is in my home office and wondering how much noise it makes

I run the air pump in my cabinet. It’s silent. As long as no wires or random items are touching it

Some air pumps are noisy but there are very quiet ones. I’ve bought many over the years.

 

[nate167]

You know how many people have snails and then get urchins and come back here saying they didn’t help?

‍ I have snails, urchin, fox face, starry blenny, hermit crabs and still fighting gha. I used old live rock that I bleached, but didn’t do an acid dip when I started the tank, and know my high po4 is coming from some of the rocks. Im leaning towards getting the surf. I like that it floats and is easy to maintain.

 

[VintageReefer]

I’m not getting that either, though I know it is often claimed.

The related claim is that trying to reduce pest algae by reducing nutrients typically fails because corals won’t be happy at the necessarily low levels.

The only way both can be true (if real) is if it’s not nutrients that limit algae in the display but something else like a trace element.

Its not impossible that the algae need something such as iron at a higher level than corals, and a scrubber drives it down.

The results are out there. The full explanation is not

My current reef ran 1.5 years and low to undetectable levels of phosphate and nitrate. My growth was exceptional

Maybe the corals absorb what they need and the scrubber aggressively takes all the excess?

I know the theory on how they work. I know the arguements on why “it’s impossible” that they work. I know the results of using them.

Someone on here mathematically proved that scrubbers can prevent display algae by having an environment that is x times more advantageous for algae growth than the display. But that doesn’t explain how corals still get what they need. So maybe the corals and scrubber both are more competitive than nuisance algae.

Or maybe it’s a trace issue as you suggested. Something algae needs that corals don’t

 

[BryanM]

After reading more, as well as experiences shared, this seems to be required in my setup soon.

 

[VintageReefer]

‍ I have snails, urchin, fox face, starry blenny, hermit crabs and still fighting gha. I used old live rock that I bleached, but didn’t do an acid dip when I started the tank, and know my high po4 is coming from some of the rocks. Im leaning towards getting the surf. I like that it floats and is easy to maintain.

Think of this like gfo. Gfo absorbs phosphate from the water, becomes maxed out. Then needs to be replaced
As phosphate is pulled out of the water, it is released from the rock. This can take a long time, and a lot of gfo changes, to actually get the numbers to stay down long term

The turf algae scrubber does the same thing. It directly consumes phosphate and nitrate from the water. 18 hours a day/night. And there is no media to replace. It just grows and you throw it out and it grows more. I found, for me, it was more effective, cheaper and easier to fix my issues compared to cheato and gfo

 

[UMALUM]

 

[VintageReefer]

 

[PharmrJohn]

I’ll let you know when I get my icp results. Mailed out last Thursday

That would be cool to see. I really am curious as to the reasoning.

 

[Fish Fan]

This thread is singing my song lol!

I have previously been in touch with @VintageReefer who recommended the Santa Monica Surf2 Algae scrubber. I am loving VR's approach and results; very much in-line with what I've been planning for my next build.

@exnisstech - I'd love your help too, if you don't mind!

And now @PharmrJohn wants one of these turf scrubbers....

It's hard to ignore the advice of that motley crew ;-) (Just joking guys, of course!)

Quickly, without trying to cross-post over the OP's thread, I am leaning towards a large sump loaded with live rock a la VintageReefer, exnisstech, etc. I want a dark/cryptic section, and I'd like to have this ATS. Seems like a great setup :)

Thanks guys!

 

[Garf]

Someone on here mathematically proved that scrubbers can prevent display algae by having an environment that is x times more advantageous for algae growth than the display

That particular chap gave up on his "model" when I pointed out a glaring issue with his presumptions. So it has not been proven as you describe. I'm not going to get into another debate with you about the benefits of growing a tiny amount of algae in a little refugium box.

 

[mizimmer90]

That particular chap gave up on his "model" when I pointed out a glaring issue with his presumptions. So it has not been proven as you describe. I'm not going to get into another debate with you about the benefits of growing a tiny amount of algae in a little refugium box.

I don't remember such a concession lol

 

[VintageReefer]

This thread is singing my song lol!

I have previously been in touch with @VintageReefer who recommended the Santa Monica Surf2 Algae scrubber. I am loving VR's approach and results; very much in-line with what I've been planning for my next build.

@exnisstech - I'd love your help too, if you don't mind!

And now @PharmrJohn wants one of these turf scrubbers....

It's hard to ignore the advice of that motley crew ;-) (Just joking guys, of course!)

Quickly, without trying to cross-post over the OP's thread, I am leaning towards a large sump loaded with live rock a la VintageReefer, exnisstech, etc. I want a dark/cryptic section, and I'd like to have this ATS. Seems like a great setup :)

Thanks guys!

Ok I’ll get us back on track

Prior to the scrubber I used that same middle section of my sump as a cheato refugium. I grew lots and lots of cheato. I sold it every week or two in large ziplock bags.

But still I struggled to keep my phosphate and nitrate numbers low. And I had hair algae in my display that would always return.

I decided to buy the scrubber and threw it in the refugium. In a few weeks the scrubber grew its own algae inside. An algae I’ve never seen before and never had in my system. Turf algae. We all have the capability to grow it, but it needs certain conditions provided by the scrubber.

What happened next? Well first all my cheato died out over a few weeks. Then my display went nuts with hair algae. It grew in spots I never seen it before. Clumps growing right out of the sand. The rock. Plug bases. Even directly out of some corals that weren’t doing great.

Then after a few more weeks…it turned white and stopped growing. I removed it and it never came back. My phosphate came down to .06 and nitrates around 5 and my display was algae free

The only time in 10 years of keeping this reef that display algae returned were times my air pump died and I wasn’t paying attention. When I replaced the air pump, the algae phased out once again after a few weeks.

 

[VintageReefer]

I don't remember such a concession lol

That is not how I remember it either lol

 

[VintageReefer]

I'm not going to get into another debate with you about the benefits of growing a tiny amount of algae in a little refugium box.

Then feel free to leave, use your own methods and move on.

 

[Garf]

That is not how I remember it either lol

Here's the thread;

https://www.reef2reef.com/threads/a...re-people-use-algae-scrubbers.1023619/page-34
Show me the proof please.

 

[mizimmer90]

Here's the thread;

https://www.reef2reef.com/threads/a...re-people-use-algae-scrubbers.1023619/page-34
Show me the proof please.

Here ya go!

To alleviate confusion around this, I decided to model the effect of a refugium/ATS and prove that growing algae in one location will have an effect on the amount of algae grown at a different location (and even has the ability to make it go to 0).

Consider the following setup of a display tank and a refugium/ATS with volumes of V0 and V1, respectively.

The Nutrients (N) in the tank are considered "well mixed", which means that the concentration is instantaneously equilibrated, and local effects are not considered, i.e. algae in the display has access to the identical nutrients in the refugium/ATS and vice versa. p0 and p1 are intrinsic rates of nutrient intake per unit volume for the display tank algae and fuge/ATS algae, respectively (these values are different because of lighting power/spectrum differences, etc. but could also be more general to measure of other factors too).

With this setup, we can model a set of differential equations that describes the change in nutrients in the water column, as well as nutrients that accumulate in algae from the display tank or fuge/ATS.

Here, N(t) is the amount of nutrients in the water column, A0 is the amount of algae in the display, and A1 is the amount of algae in the refugium (both A0 and A1 are in units of nutrients). We can also model a constant influx of nutrients to the tank (i.e. through feeding). In this model, I assume no outflow of nutrients, so the sum of N, A0, and A1 is always increasing by c*t.

Solving these differential equations for N, A0, and A1 yields the following:

Now the neat thing about this is that the growth of algae in the display is proportional to the ratio of intrinsic growth of the display and its volume by the total algal growth (p0V0 / (p0V0 + p1V1)). If we take this to the limits and have a significantly larger Fuge/ATS than the display tank, we can see the algae growth in the display tank goes to zero!

This is a proof that your model is wrong! Algae grown in one side of the tank *DOES* influence algae grown at another, and a sufficiently large fuge/ATS *CAN* completely outcompete algae in the display.

So, finishing our discussion: if a fuge/ATS doesn't work, it's NOT because algae grown at one location can't compete with another location.

Backing up though, how many of us have a fuge/ATS that's larger than our tank?? I doubt many! So what might these curves look like in practice? Well, I computed the nutrient/algae growth as a function of time from the above derivations and there's some informative data!

First, imagine we have a fuge the same size at the display, with identical lighting power/spectrum. Both A0 and A1 curves are the same (green and red respectively, though green is completely overlapped by red in this plot; free nutrients as black curve) and the ratio of algae in the display and in the fuge is 1 (seems reasonable!). BTW, code is in python and available on request!

Next, convincing ourselves that it's possible for a mega sized fuge (100x the display with a comparative advantage of 10x!) to completely out compete the display tank. A0/A1 ratio is 0.001(this value actually just ends up being the ratio of (P0V0)/(P1V1) so I'm dropping it from subsequent plots.

Okay, I know you're saying this isn't realistic! So what about a fuge that's half the size of the display (still a big fuge) with lights that give a 10x advantage (this is a guess but we can throw this parameter around). Doesn't look too bad! definitely helps, but this model predicts significant algae still growing in the display (green curve).

What about a significantly smaller ATS (5% of tank volume) with bigger advantages (50x comparative advantage to display)? Similar split.

What if we have an underpowered fuge/ATS? lets say same size as above but only a 10x advantage to the display?

Now the algae in the display starts to win! Though its important to notice that the display algae is still much lower than it would be without the fuge/ATS.

Now, I wouldn't read into exact values (a little arbitrary), but this shows how we can tune the knobs of our system and how it will influence the tank!