Algae Scrubber Basics

[EricDP]

Any reason this thread isn't pinned? It hasn't had many updates lately, but is still super relevant... and search did not find it easily, even though the exact title was mentioned in many other threads.

 

[EricDP]

I've put my first ATS together using this thead as the primary source. It is fed directly from the overflow, and flow rates are appropriate to the length of the slot as suggested here. However, it runs quite loud. I'm thinking maybe the slot is too tight, causing the water the spray through? Does this look like it's running too... restricted?



Note: in the test, it's just running fresh water, but it sounds about the same with sea water...

 

[Turbo's Aquatics]

What flow rate did you figure? Did you measure it using a pitcher and timer?

Keep in mind, the original target rate of 35 GPH/in is actually what I now consider the maximum. You can use a lot less and still have very effective results.

Based on the video, I see arcing which means the flow could be a bit high. The slot being too narrow is possible as well. It's a very fine line though, widening the slot by as little as 1mm might be too much, so this is going to be a bit of trial & error.

When coming directly off the overflow, I would make sure you have some kind of emergency bypass/diverter up high on the drain pipe. That allows for an alternate route for drainage without losing your pressure on the slot.

 

[EricDP]

Keep in mind, the original target rate of 35 GPH/in is actually what I now consider the maximum. You can use a lot less and still have very effective results.

Hmmm... I was unware of that. Flow rate is about 250Gph going into a 7-inch slot, so I guess that is the max. I measured flow from the output of the (fully plumbed) return, flowing into an empty tank, into my 2L measuring cup.

So if I'm running max, I'd need to ensure the slot was at least the suggested width, and maybe a touch more. Re-reading the thread, I see the recommended slot width is 1/8" (a little over 3mm). I think mine is a bit less than that (closer to 2.5mm) so I'm going to try to expand it a bit... just trying to find the right tool. The dremel sinks into it like a hot knife in butter, and I've destroyed a few pipes trying to do minor touch-ups with it. Maybe a file... could take a while, but be more accurate.

For emergency bypass, it’s a Herbie overflow and the tall pipe bypasses the ATS completely, flowing into a different chamber of the sump, so that should be safe.

Thanks for your thoughts! :)

 

[Turbo's Aquatics]

Yes, 2.5mm is a bit tight. 1/8" is roughly 3.2mm so I'd widen it a bit.

You're right, any way of cutting the slot is the difficult part for sure. When I was making these for my scrubbers (Rev 1/2/3) I used a jig to hold the pipe, then a plunge router - which would be pretty dangerous without a jig, and is pretty hairy even with one.

Another factor is the pipe material Schedule 40 is thinner so it can close up in the middle after you cut it. Schedule 80 is better, and anything under about 9" or so will stay the same width. Anything ~12" or so will still close up in the middle over time but not as bad as s40.

Herbie emergency pipe might be OK. I would make sure to test it though, just to make sure. It's a clog (snail, etc) that is the concern.

 

[EricDP]

I set my rotary tool to min speed and found it to be far more forgiving. I could "buff" the slot, adding a fraction of a mm per pass. When the bit would bind, it would just stop, rather than taking a big chunk out. With some care and a lot of patience, I've expanded the slot to between 3.0 and 3.1 mm for the entire length, and it's now much quieter. More like a garden fountain, where before it was a waterfall. I'm thinking it'll probably be quiter still with algae on it so will leave it for now to see how it matures. Thanks for your help!

 

[Turbo's Aquatics]

Great article on the relationships between algae and bacteria (technically, for heavy metal wastewater treatment, but I think this is relationship is more generic than that).

I like this graphic in particular

Algal-bacterial symbiotic system for treatment of heavy metal containing wastewater: performance, mechanisms and applications - npj Clean Water

In algal symbiotic systems (ABSS), bacteria and algae establish mutualistic, commensal, or parasitic relationships, leveraging their respective biosorption and bioaccumulation mechanisms, along with symbiotic effects, to effectively treat heavy metal (HM)-containing wastewater. The HM removal...

www.nature.com

 

[69cam]

This should be pinned?

 

[mattrob]

@Turbo's Aquatics
@SantaMonica

Thanks for all the great advice on this thread, im currently 3d printing an algae scrubber similar to the new adaptive reef ai blade hybrid design (the box fills with water and falls over 2 screens) as I had an ai blade refugium from an old attempt at a refugium.

I have been following the advice but think I might have made the screens too large, my question is, as I have enough flow for the full 8 inch width of the screen but current load is 1 cube, if I only rough up 24 square inches on each side and leave the rest smooth, will this be ok? If so, i assume i am then able to rough up more if the bioload increases?

I will add I've had algae problems in the display for months, and only just stumbled onto the idea of a scrubber

Many Thanks

Matt

 

[Freenow54]

Dedicate Algae Scrubber Basics website (freebie site, why not): http://algaescrubber.zohosites.com/

Just joined here, I have the same username on several other forums. Not everyone is on multiple forums so I figured I would join up here and share expertise and tips on DIYing Algae Scrubbers.

As is with most other forums, getting into drawn out discussions about what they are capable of seems to "light a fire" for some reason. That may not be the case here. But for now, I would like to try and keep this thread more along the lines of how to build, maintain, and troubleshoot your DIY Algae Scrubber build. So if you want to build an Algae Scrubber and have questions, I'm here to help.

There is a site that is pretty much no-holds-barred info about scrubbers and if you're slick enough with google, you'll find it. I'm not familiar with R2R's policies so I will refrain from a direct link.

I'll post some info on the tank that I run a scrubber on soon. Just wanted to stick my head out for now.

Cheers!

I get a 404 fault from your link

 

[Turbo's Aquatics]

I have been following the advice but think I might have made the screens too large, my question is, as I have enough flow for the full 8 inch width of the screen but current load is 1 cube, if I only rough up 24 square inches on each side and leave the rest smooth, will this be ok? If so, i assume i am then able to rough up more if the bioload increases?

I would just rough it all up now tbh. It will be a pain to do it after. Having too much surface area is a relative problem - 1 cube vs 2-3 cubes, not a big problem. If you feed 4 cubes and have a 12 cube screen, that can be a problem. However it's not just the screen, it's also the light (intensity, proximity, spectrum, duration), the flow, diversity/age of system, and other filtration. So if you have a 2-3 cube screen and only light it like it's a 1 cube screen, you're "light limited" and the screen size being too large should not be detrimental.

I get a 404 fault from your link

Yeah that site sucked and I let it die. It's basically the first set of posts on this thread. Or here
https://www.algaescrubbing.com/resources/ but registration is disabled because 1) dead 2) spammers

 

[mattrob]

I would just rough it all up now tbh. It will be a pain to do it after. Having too much surface area is a relative problem - 1 cube vs 2-3 cubes, not a big problem. If you feed 4 cubes and have a 12 cube screen, that can be a problem. However it's not just the screen, it's also the light (intensity, proximity, spectrum, duration), the flow, diversity/age of system, and other filtration. So if you have a 2-3 cube screen and only light it like it's a 1 cube screen, you're "light limited" and the screen size being too large should not be detrimental.


Yeah that site sucked and I let it die. It's basically the first set of posts on this thread. Or here
https://www.algaescrubbing.com/resources/ but registration is disabled because 1) dead 2) spammers

Thank you

 

[SantaMonica]

I have been following the advice but think I might have made the screens too large, my question is, as I have enough flow for the full 8 inch width of the screen but current load is 1 cube, if I only rough up 24 square inches on each side and leave the rest smooth, will this be ok? If so, i assume i am then able to rough up more if the bioload increases?

If you are making it like the AI one with 1-sided vertical screens then try to get a sheet of solid white plastic behind the screen to reflect light to the back sides. It's not as good as a 2-sided screen but it helps when the screen holes are open and light gets through.

Rough it all up now. If you want to use less, then just block off the water outlets.

Most important make the screens very rough; not smooth like the AI..