Mega Powerful Nitrate and Phosphate Remover - DIY!

[SantaMonica]

Even at tremendous flow velocities, it will only become thinner,

Yes thinner is what we want.

Turbulence does however have the benefit of capturing dissolved carbon dioxide from the atmosphere and transfering it to the boundary layer

Yes we want this too.

It stands to reason that you would want to expose the culture to as much air as possible without drying it out in order to maximize it's growth.

That's why one of the advanced options is to pulse the flow, and add a fan. This also gives you a different type of algae.

And of course, a scrubber's thin layer of water is what makes all this so efficient (compared to a fuge).

 

[rocker85675]

Yes FW too.

For large tanks, just frame it out:

... although you'd want lights on the outside too.

with THAT light i would grow a different kind of green

 

[cvermeulen]

Just thought I should mention that the boundary layer in a fluid system can never be removed. Even at tremendous flow velocities, it will only become thinner, never actually disapearing. Turbulence does however have the benefit of capturing dissolved carbon dioxide from the atmosphere and transfering it to the boundary layer, where it can move across by osmosis, to become available to the algae/moss culture. Too much turbulence, or flow velocity will stress or damage the culture.

The boundary layer never goes away, but a boundary layer is not holding still, either. The 'boundary layer' is just a layer of slow moving fluid near an object that the main flow is moving around. 'slow moving' refers to the fluid's velocity relative to the direction of the main flow - in a turbulent layer, the fluid is eddying - flowing away from the wall, towards the wall, and even against the direction of the main flow. This whole turbulent effect I think is probably a better argument for using screen over plexiglas, than the cleaning issue, as the holes in the screen will disturb the boundary layer, creating even more turbulence and exchange between the flow surface and the algae. In this sort of setup, I'd hazard that the flow is so thin that a conventional boundary layer does not even exist, as it's existence is complicated by the air-water boundary, and the thinning of the flow as it picks up speed down the screen, blah blah blah.

Osmosis is the transfer water across a membrane motivated by water solvent potential, and occurs at the algae layer in th ebiological process, but not in the boundary layer.

Anyway, the bottom line is that the device appears to grow algae like crazy. I never got to building one last weekend, but I've got plans. The only thing I don't like about my design is that the scrubber is before the mechanical filter, so it has potential to clog. I've built in a bypass in case it clogs up, but I don't know what might happen if say a feeder goes down the overflow pipe, or my MTS start getting into the works.

 

[SantaMonica]

Today's success story comes from "BearUSA" on the TR site. He did what many folks call the "combined" approach... using lots of things in addition to his scrubber to help eliminate his nuisance algae. Wish he had more pics, but here is the before:

And after:

Hi-Res: http://www.radio-media.com/fish/UserBearUSAonTalkingReef-10.jpg


Here is his setup:

And here is what he said along the way:

8/21: this guide is awesome, i,m gonna be building me one of these as soon as i get some time to myself, thanks for posting this so everyone can see and share.

9/10: what is the best way to get rid of nuisance algae, despite regular water changes and picking this stuff off the rocks it keeps growing back, my nitrates are 0ppm confirmed with 2 different test kits. my phosphates are also 0ppm with different tests. i have since set up a turf algae screen but that has only been running for a day and a half so its not working yet.

9/10: [waterfall pipe is] just an ordinary gravel vac pipe, fed by my external canister filter, the light is above at the mo i need to go out and buy some brackets and 2 light fixtures so i can have a light either side of screen, the other end of the gravel vac pipe has a water tight access plug, so i can still get in to clean the pipe. this nuisance algae just keeps on growing despite regular water changes picking it off the rocks, this stuff is ugly no matter what i do it just dont wont to disapear, this turf filter is my last resort.

9/13: i am determined to get this right but sometimes its so disheartning to see a tank that you try your very best to get things right to just keep getting covered in crap algae.

9/18: over the last couple of days i have noticed the nuisance algae i've been suffering with is eventually starting to die off. i'm sure the second 60 litre tank that i placed my calurpa green grape and cheato are starting to take up the nutrients before the nuisance stuff, i'm so pleased today that my tank is half way to looking great again.

9/20: i have done 2 small water changes whilst siphoning out as much as possible, i'm quite glad now i,m eventually getting back on track, my water is crystal clear all params are spot on, i had feared of water turning a bit yellowy with the release off the nutrients from the dying algae but i have had none of that. [...] hopefully fingers crossed i,ve got a hold on this now.

9/23: [answering "how did you do it"]: it could be a number of elements, i took on board all the advice which i received which im totally greatful for, i set up a 60 litre tank next to my main dt and filled it with a 4 inch deep sand bed, plus added culurpa green grape and cheato, i set up a temporary turf algae filter as suggested by Santa Monica in his thread under mega powerful nitrate and phosphate remover, i have continuously picked at the stuff and used a toothbrush to gently wipe over the rocks and inside the nooks and crannys, no doubt scaring my fish half to death, the only thing i haven't done yet is to replace the skimmer, i should say upgrade the skimmer, currently running a red sea pro prism, i had advice to get rid of it and get a better one. and also added another koralia 2 to improve water circulation which i placed at the bottom of dt to serge current over sand bed. increased slightly the amount of water i take out for water change, from about 90litres to about 125litres every 2 to 3 weeks. on the whole it could be any number of things i have done if not all, and once again i would like to thank all of you for your advice and recommendations.

10/6: this thread is really getting interesting now with all the different people posting and for santa monica posting pics of the scrubbers, etc. GOOD WORK SANTA MONICA KEEP IT UP

10/9: i,ve nearly cracked it, this nuisance algae have a look at these pics to see, i'm over the moon its nearly all gone.

10/16: i've been running my scrubber for about a month and a half now, n and p are zero, i have always had a zero n and p reading using the salifert test kits, but when i had that nuisance algae problem i was told the kits were registering zero because it was quite possible that the algae were taken it all in. if that makes any sense. ps another note i'd like to thank you again for your hard work and commitmant in keeping this thread a live and with the great pics your posting up, keep up the good work, without your posting of this thread i wouldn't have even known about these turf filters, so once again a BIG THANKYOU.
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[Potts050]

The boundary layer never goes away, but a boundary layer is not holding still, either. The 'boundary layer' is just a layer of slow moving fluid near an object that the main flow is moving around. 'slow moving' refers to the fluid's velocity relative to the direction of the main flow - in a turbulent layer, the fluid is eddying - flowing away from the wall, towards the wall, and even against the direction of the main flow. This whole turbulent effect I think is probably a better argument for using screen over plexiglas, than the cleaning issue, as the holes in the screen will disturb the boundary layer, creating even more turbulence and exchange between the flow surface and the algae. In this sort of setup, I'd hazard that the flow is so thin that a conventional boundary layer does not even exist, as it's existence is complicated by the air-water boundary, and the thinning of the flow as it picks up speed down the screen, blah blah blah."




Again I reiterate that the boundary layer cannot become turbulent. It is by definition a stagnant layer between the fluid and it's impoundment. It is very thin and depends on four things;

1. The viscosity of the fluid
2. The velocity of flow across the surface
3. The roughness of the surface it adheres to, and
4. The electrochemical properties of the material/impoundment surface.

"Osmosis is the transfer water across a membrane motivated by water solvent potential, and occurs at the algae layer in the biological process, but not in the boundary layer.

You are correct. The term I should have used was 'difusion', the movement of a dissolved compound from an area of high concentration to one of a lower concentration

Anyway, the bottom line is that the device appears to grow algae like crazy...

I agree although I'm still leaning towards a refugium. It just looks better

 

[cvermeulen]

Again I reiterate that the boundary layer cannot become turbulent. It is by definition a stagnant layer between the fluid and it's impoundment.

Sorry, You're incorrect. Wikipedia has a good coles notes on boundary layers if you want to read more. The only area with zero velocity is right at the interface between the water and the surface the water is flowing around (see 'no slip condition') - maybe this is what you're thinking of. The boundary layer is in fact moving; The edge of it is defined as where the flow is only 99% of the free-stream velocity (therefore, by definition, the boundary layer is moving)

I'm still leaning towards a refugium. It just looks better

Well I tend to agree - quite a few of the installations are quite unsightly - but they can be hidden. I have a refugium on my tank right now, and I'm trying to work my algae screen into the waterflow from the tank into the sump/refugium. That way I can put feeders and inverts in my refugium.

 

[zennzzo]

Woooot!
OK we have what looks like the start of something very interesting...
Here's the thing it's down at the bottom where it gets the least amount of direct sunlight...??


I'm really liking this new Camera...you can even see where I roughed up the Plastic Canvas with 80 grit

 

[SantaMonica]

Cool. That's just where some algae stuck when you set it up.

Did you look into a foil reflector?

 

[zennzzo]

Cool. That's just where some algae stuck when you set it up.

Did you look into a foil reflector?

No, I'm going to see what this will do.
The canvas was seeded with what I could, and then rinsed thoroughly. That's something you said in the thread. There was no visable green on that canvas...

 

[SantaMonica]

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Update of the Day:

It's been recently discovered that the screen-wrapped-around-pipe design will clog up and stop working when the algae gets thick. It grows heavily where the screen is wrapped at the top, and blocks further flow from going down the screen. Instead the flow starts going out the ends, completely missing the entire screen, thus killing what algae was previously growing on screen. It affects different screens in varying amounts; the higher the lights are (thus closer to the wrap), the more it clogs. This is the type I'm referring to:

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