Algae Scrubber Basics

Hmmm. I'm moving so I'll be tearing my system down. In the interim, I'm going to set up an outside tank in my dad's house and going super duper cheap.

The idea is to use a 300gal Rubbermaid stock tank and then use just a scrubber and air injector. The scrubber will be mounted higher making the DT effectively the sump... should be a very cheap backyard build. Still MH lights though but might go solar for the scrubber!!!!

If I'm right, the corals should continue to grow just as fast as they're doing in my big expensive tank.

This will be the ultimate test though... just scrubber and air. Even the live rock is out. The only in-tank structures will be my concrete covered PVC...
 
Hah! That light was a scam. It's "1000W of light" but only consumes "200W" of power. They mean that it's comparable to 1000W bulb- still false advertising imo.

So not comparable to my 500W real LED power DIY.
 
karimwassef said:
Hah! That light was a scam. It's "1000W of light" but only consumes "200W" of power. They mean that it's comparable to 1000W bulb- still false advertising imo.

So not comparable to my 500W real LED power DIY.
Click to expand...

You didn't notice that? #1 thing to always look for is actual LEDs and rating - that one had 100x 10W, but that wattage rating is just marketing so their "average power draw 180-200W" tells me they are running those at well under the rated current, probably because their heat sink sucks so in order to extend life they knock it down, either that or their driver sucks and pushing it any harder would cause it to blow up.

This is pretty much the case with every off-the-shelf product, you have to pay for the good stuff, there's really no getting around that.
 
Algae Scrubber Suddenly Halts as N & P Dropped

Got a quick question.

My DIY Algae Scrubber has been doing great over last year. During peak stage is was producing many Grams of Algae every other week at harvest time.

Initially it went through the Slime Stage, and then Matured to the Stringy Green Hair Algae, then more into a Macro/GHA Algae mix that needed Light Screen Scraping.

Just before it stopped, it started producing a thicker macro Algae that came out like butter.

I was always running GFO very lightly and after changing media P dropped again....

As Nitrate = 5ppm and Phosphate continued to drop, at P=0.04ppm the Scrubber stopped to a screeching halt.

I do have some snail in the Scrubber since it's built into a Sump, and they polished it clean as seen below.

36108965894_9fd27c5645_z.jpg


I first thought why not increase photo period so I increasd from 18 hours to 20, then to 22 hours and that hasn't done a thing.

Nitrates are rising N approx. 25ppm, and P around 0.12ppm. But Scrubber is still idle.

So now I reduced photo period down to 12 hours, hoping it kicks in.

It this normal? Is photo reduction the thing to do?
 
algae needs both N and P. By running a GFO, you're starving them.

You need balance, so do some water changes to reset. Feed more and it should fix itself
 
Doesn't need nearly the amount of P vs. N. Many may still need to run GFO or not. Just need to make sure there's a detectable amount.

My system is continuously at around 2.5-5mg/L of Nitrates and around 0.02-0.09ppm of phosphates. Scrubber growth is good. So, to me those numbers above are not a limiting factor. Possibly other trace elements are like Iron, Zinc, etc.
 
the ultimate test though... just scrubber and air
Click to expand...

One main thing different is the lack of periphyton on the rocks, which generates a lot of food particles.

You'll certainly want to have separate units, at least three, and clean only one at a time (if you are cleaning; which of course is not needed if seeking a self-sustaining system).

Scrubber has been doing great over last year
Click to expand...

It's doing what it does: grow less for less nutrients. Just keep the slime off the screen, and let nutrients rise again, and feed more if you want.
 
karimwassef said:
algae needs both N and P. By running a GFO, you're starving them.

You need balance, so do some water changes to reset. Feed more and it should fix itself
Click to expand...

This is a SPS only tank. 3rd attempt so rebuilt, re-designed, and totally automated for stability and Max Nutrient Import/Export.

My system has a DIY Controller Based Water Changer. (One push of a button. Does WC in custom Sump section. Easy so I do WC regularily).
I do 5 % Water Changes twice a week, using Tropic Marin PRO Salt which should be keeping all Elements up.

I don't dose Potassium which is one of the more important Elements for Algae, and it's at 400ppm. Thus I trust the other elements are fine too.

Yes, feeding more might be the trick. I feed 2-3 times a day a variety of Flake, Pellets and Frozen Food.

I know there are nutrients flowing thru Scrubber since Scrubber is First Stage. Skimmer 2nd stage, and Skimmer Cup fills up with Thick Skim every few days.
Here is the Sump Design with Built in Scrubber. Refuge area shown in this thread was converted into the Auto Water Changer Compartment when I built the Custom Controller.
Custom Sump (Rebuild) 50 Gallon Multifunctional (TEST RUN) YouTube

The part that puzzles me is not much has really changed from when Scrubber was an Algae Factory.

Sure P dropped, but it's still there 0.08ppm (Just tested). N is just under 25ppm. That should be good enough.

GFO is in last stage, so doesn't steal any P from Scrubber. And just a tiny trickle thru reactor.

Let me see if Photo Period Reduction helps.

One really Crazy theory I have, is I have a Large Cowrie Snail in the Scrubber (Size of golf ball, but can devour GHA like a monster.). Plus a few snails.
I took him out of DT since he started eating SPS polyps and threw him into Scrubber to Enjoy the buffet.
Could Cowrie be eating all the Algae the Scrubber makes. That would re-cycle the N &P since Algae not removed.
If Cowrie could eat it all that would make it kind of a like a Perpetual Nutrient Machine.

[(1) Algae eats N & P, (2) Cowrie eats Algae and makes nutrients(Poo), (3) Corals Eat Nutrients (Poo from Cowrie), (4) Skimmer removes bad stuff]
If this is truly happening, then it might not be a bad thing. A self cleaning scrubber. Too good to be true.

I doubt it. Not Possible. Must be something else. Could a Cowrie eat 100grams of Algae in two weeks? That is what the Scrubber used to produce when N & P was higher.
But if he can eat (100Grams/60days =1.6 Grams of Algae A day) , that could explain one thing. P has dropped more then N.

Shouldn't N be reduced as effectively, but it doesn't since it's being recycled by the Cowrie.
Plus if scrubber slowed down with lower P then maybe he only needs to eat a gram a day.
What I noticed during the slow down is less and less Macro Algae was building up in the ATS. Eventually I removed that last piece.
He may be cleaning the Fine Algae building up on the screen.

I am no expert, thus recruiting the experts on this Forum to help me solve this mystery.
 
Last edited:
No.

Skimmers remove dissolved organics, not inorganics. You're removing food and bacteria - not N and P.

I run SPS without a skimmer or GFO. Algae is all you need.

The ratios of N and P should be in balance, not equal.

The cowrie creates a recycling loop but it must go through algae... inorganics > algae > eaten and turned to poo > organics > inorganics > repeat.

The middle part can go several ways...

poo > bacteria > skimmer export
poo > bacteria > sponge food (sponge sequestration)
poo > pods & worms > coral food (coral sequestration)
poo > inorganics + light > algae food (algal sequestration)
poo > inorganics + light > algae food > algae export

There's plenty of other possible chains - but they all come from poo and go back to poo

The food chain is a beautiful thing
 
karimwassef said:
No.

Skimmers remove dissolved organics, not inorganics. You're removing food and bacteria - not N and P.

I run SPS without a skimmer or GFO. Algae is all you need.

The ratios of N and P should be in balance, not equal.

The cowrie creates a recycling loop but it must go through algae... inorganics > algae > eaten and turned to poo > organics > inorganics > repeat.

The middle part can go several ways...

poo > bacteria > skimmer export
poo > bacteria > sponge food (sponge sequestration)
poo > pods & worms > coral food (coral sequestration)
poo > inorganics + light > algae food (algal sequestration)
poo > inorganics + light > algae food > algae export

There's plenty of other possible chains - but they all come from poo and go back to poo

The food chain is a beautiful thing
Click to expand...

That for the explanation. What is your N & P in your "Algae Export" "NO Skimmer/GFO" SPS Tank setup?

What if I stopped my Skimmer, which is producing a thick cup every week.
I know the scrubber is a good design and works effectively.

The scrubber should really kick in, regardless on how much the snails and Cowrie are eating off the screens.

Turning Scrubber off terrifies me. Wish I could test this without DT involved.

So it sounds like this has nothing to do with Photo Period on my mature screens.

And...I probably can feed the Fish much more. However could I feed corals with Coral Foods without Skimmer?

BTW. I put a Time Lapse camera on the Scrubber overnight. Snails are continuously running across the screens cleaning them. Haven't seen Cowrie yet.
 
Last edited:
N and P are below measurement

My corals grow at a frantic pace because there's food (organics) in the water, not inorganics.

There's this myth than there's a minimum N and P needed for healthy coral growth and color. In the wild, healthy natural reefs have no measurable inorganics but massive organics. The normal food/waste cycle provides all that is needed for zooxanthelle to work.
 
1.- does any one using a ATS has experience dosing H2O2 for cyano?
there is a study that suggests dosing H2O2 14 days to eradicate cyano, but I am not sure if it will affect the algae filter?


2.- do any of you using ATS has tested Potassium in water?
I wonder if algae consumes potassium at a rate that it needs to be dosed to the tank to have good levels for the health of the sps?

thanks for your answers
 
sensei said:
2.- do any of you using ATS has tested Potassium in water?
I wonder if algae consumes potassium at a rate that it needs to be dosed to the tank to have good levels for the health of the sps?

thanks for your answers
Click to expand...

I just tested and K=400. But I do frequent water changes.
 
karimwassef said:
Oh. I don't export. I sequester and recycle algae.
Click to expand...
You said above in your first post that you run a scrubber only, but no skimmer. Yet your ID Footnote say's DIY 12' Skimmer (is that out of date).

Would you suggest I try turning off my very active skimmer and see if Scrubber kicks in (And SPS also improve)?

Can you explain what "sequester and recycle algae" means?
 
yes. I built a massive skimmer and then stopped using it and converted it to an air injector only.. basically, the head of the skimmer.

I did this because the organics it was removing was coral food that I needed to keep in the tank.

I would only take the skimmer offline if your scrubber is active and healthy. You can try turning it down to experiment.

Sequester means that the algae continues to grow and I don't remove it.
Recycle means that when I do remove any of it, I feed it back to my DT to turn it into poop = food for my corals.

If you have mechanical filtration, you're actively turning good organics into wasteful inorganics.

This is my experience.
 
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