Algae Scrubber Basics

[jason2459]

I found that diminishing rate of return on the flow. Past two weeks I had my ATS pump on full for the first time and it did not work out so well.

Front

Back

So I cleaned it off and throttled the flow back a bit again

So I think I'll set it to this again for a couple weeks and it should come right back. I don't know if I should increase the lighting period a bit or wait a couple weeks for it to produce that nice thick mat again.

Now on the awesome side my ORP plummeted during this time frame and is about 380 just before the ATS LEDs turned off this morning and is at 368 right now. So I kind of was assuming something wasn't right and my theory was right. Ha!

This I think makes a much more solid case the ATS is directly effecting the ORP levels. Now to see if it at least stabilizes over the next two weeks. I'll have to pull my ORP graphs for the past couple weeks later.

 

[jason2459]

Looks like the graph can only do 7 days at a time.

So, here's the stats for the past 7 days which has been hovering around 350-360's the past few days on average during the lows.

Overall Minimum: 346 Average: 365.15 Maximum: 383
Selected Minimum: 346 Average: 365.15 Maximum: 383

But here's a good graph representing what I was watching and shows the dramatic drop I mentioned above. You can see it going up every night with the LEDs on but it wasn't keeping up with the daily drop.

 

[sensei]

Scrubber vs Refugium:

Scrubbers compared to refugiums

A not-so-obvious difference is that a scrubber, if run together with a fuge with macros, will kill the macros even though the macros are much larger. This is because the scrubber thinks the macros are nuisance algae. Some people do run both together without killing the macros, but this is just because their scrubber is not strong enough, and actually the macros might even be slowing down the scrubber because the scrubber thinks it has to remove the macros, along with the nutrients in the water and the nuisance algae in the display. However if this works for them, good.

I do not understant the statement "the scrubber thinks the macros are nuisance algae"??

If understand correctly, the scrubber and the macro in fuge will both compete for nutrientes in water, and it seems that the scrubber has more potential to absorve the nutrients and can starve the macro algae in fuge as well as green hair algae in DT. please let me know if I got the concept.

Thanks

 

[Floyd R Turbo]

Yes, you have it right.

 

[sensei]

Floyd,
If you oversize the algae scrubber, is it possible that tha algae will consume to much nutrients to a level that is not desirable by the corals??
I ask because I understand that before the size was based on the tank size and not the feeding load and I do not know the results of such scrubber vs the ones size based on the feedings?

thanks a lot

 

[SantaMonica]

Scrubbers cannot "over scrub", because they use the same mechanism for filtering (photosynthesis) that corals use to grow. So, when nutrients are low, both react the same.

The opposite can be said of pellets, gfo, nitrate reactors, etc; they don't care what the status of the corals' photosynthesis needs are.

 

[karimwassef]

Basic question- what drives the GHA to preferentially form in the scrubber vs the main DT?
Flow, light, competition, substrate?

If I have nutrients to grow GHA in the scrubber, why not in the sump or overflows?

Second- Refugia can develop cyano as bacteria builds in the chaeto. Is GHA immune to this?

 

[Floyd R Turbo]

karim, those are good questions.

Some people still battle algae growth in DT areas with high flow and lighting. overflows are a pretty good example of this, because you have high flow, and usually, the lights are right there so intensity is good. A scrubber will compete with this growth, so you generally should see less of this, but unless you are making notes of how often you clean off your overflows and how much you harvest (by squeezing and weighing) prior to installing the scrubber, it's hard to see the difference a scrubber makes.

Also, the overflows are an area where algae gets "first crack" at the dirtiest water.

In the sump, if there is no constant light source, then algae will have a very hard time growing. But if there is one, then yes, you might get some growth, but the preference goes to the area with the ideal conditions - the scrubber. So you would likely see less algae in the sump, but you might get some, it just likely won't get out of control extremely fast.

For refugia, usually you don't have high-speed laminar flow, so cyano and other nuisance issues can easily take hold if the conditions are right. Not really the case with scrubbers, of just about any kind. You might see some, but it's either a transitional phase (maturing cycle) or maybe a coating over the top. But the flow is what keeps it from taking over.

 

[sensei]

Scrubbers cannot "over scrub", because they use the same mechanism for filtering (photosynthesis) that corals use to grow. So, when nutrients are low, both react the same.

The opposite can be said of pellets, gfo, nitrate reactors, etc; they don't care what the status of the corals' photosynthesis needs are.

Thanks a lot, this answers my question!

 

[SantaMonica]

Think of photosynthesis as a vacuum suction; which ever macro has the stronger suction, get the nutrients.

The trick is to figure out how to have the stronger suction.

 

[hkgar]

Also, the overflows are an area where algae gets "first crack" at the dirtiest water.

Floyd
My scrubber flow come from the return line, which would probably be the "cleanist" water. Should I consider installing a pump to feed the scrubber?

 

[Floyd R Turbo]

I think that this only really makes a difference if/when you are having problems getting the screen started. Otherwise no, because filtration doesn't typically purify water in one pass.

 

[Reef Frog]

Let's say we have an aquarium with a properly sized & productive ATS with your typical hair algae. Will the scrubber likely be beneficial in reducing or limiting the growth of other species of algae. For example the very different species like bubble algae & the various turf algaes?

Will it do much for a tank with minimal or no hair algae, but has other species growing? Does this well tuned ATS typically starve & kill these more difficult species, or just slow down their growth? For really tough cases, are any complimentary tactics useful like a lights out period etc. ?

Anybody out there that's completely tamed bubble algae with an ATS for example?

 

[Spar]

What is the best practice for a very gradually growing bioload tank?

For example i will only have coral and inverts for the first 6-12 months, feeding hardly even 1 cube worth per day likely. I will then very gradually add fish over a year or two span, gradually rising from 1 cube to 6 cubes per day.

Is it feasible to build my ATS for a 6 cube per day system, but only rough up the screen for the portion of size equivalent to what my current feeding rate is? I.e. I will gradually increased the rough portion of the screen over the next couple years, while leaving the rest smooth.

Thoughts on this method?

 

[Floyd R Turbo]

Let's say we have an aquarium with a properly sized & productive ATS with your typical hair algae. Will the scrubber likely be beneficial in reducing or limiting the growth of other species of algae. For example the very different species like bubble algae & the various turf algaes?

Will it do much for a tank with minimal or no hair algae, but has other species growing? Does this well tuned ATS typically starve & kill these more difficult species, or just slow down their growth? For really tough cases, are any complimentary tactics useful like a lights out period etc. ?

Anybody out there that's completely tamed bubble algae with an ATS for example?

Every tank is going to be different, but in general, an algae scrubber that is strong enough should eventually out-compete all other algaes. Some are particular tough, and some strains are notoriously difficult. A severe infestation of bubble algae or bryopsis come to mind. I've had bubble algae that disappeared over time and never came back. I've never had bryopsis but that's the one where most tend to have to take extreme measures, like manual removal with a tweezers and running GFO or RowaPHOS, etc.

What is the best practice for a very gradually growing bioload tank?

For example i will only have coral and inverts for the first 6-12 months, feeding hardly even 1 cube worth per day likely. I will then very gradually add fish over a year or two span, gradually rising from 1 cube to 6 cubes per day.

Is it feasible to build my ATS for a 6 cube per day system, but only rough up the screen for the portion of size equivalent to what my current feeding rate is? I.e. I will gradually increased the rough portion of the screen over the next couple years, while leaving the rest smooth.

Thoughts on this method?

If you build a scrubber that is vastly oversized, you might run into issue with the growth being thin, but that doesn't mean it is counter-productive - just a less efficient use of space. it will still filter. Rather than not roughing up a particular section, just don't light it.

Better yet, start with a smaller scrubber, maybe 2-3 cubes/day and adjust the capacity with factors like light intensity/photoperiod and flow. You can ramp these up and down and get different levels of production.

Then as your system grows and (if) you max out the screen capacity with lighting and flow, then you cut a new slot pipe and add the second screen section and double the lighting. Or, you make a whole new screen and cut the old screen into strips and tie to the new one to quick-mature the new screen.

 

[karimwassef]

So - just thinking through this -

For a large flow, high volume design:
1. One light source (series of lights) in the middle of two sheets
2. Each sheet is 4ft wide x 2ft wide ( x 2 sheets ).
3. Assume that flow can be limited to 3000 gph.
4. Total system volume is 660 gal.
5. Water source is from DT overflow to the sump.
6. Warm CFL (125W x 4), one over every foot of sheet.
7. Injection from a 2" PVC split into two 1" PVC pipes with 1/8" slits.

any major gaps?

 

[Floyd R Turbo]

Why so huge? If you go by the feeding guideline, 48 x 24 =1152 /12 is a 96 cube/day scrubber, are you really feeding that much?

35 x 48 = 1680 GPH so you would be way over on flow

1152 sq in needs nearly 600W of light per side, which you've nearly got covered, but 125W CFLs are going to have a huge bright spot which will mess with growth due to focused intensity, so you're going to have a bit of a time finding the right distance and photoperiod without burning the algae.

Not sure I'm following the 2x 1" pipes thinking, or were you planning on 2" into a tee, down to 1" and a 2' screen in each direction?

Still, it comes down to the need for a scrubber that large. I just don't see it

 

[karimwassef]

I travel a lot, so I need something that can go without cleaning for a long period of time.
My tank is also open to the elements to some extent (garage) and I live by a lake. The mass of insects that find their way through the layers of plastic sheets to get to the tank is huge. I regularly scoop the equivalent of 2 or 3 cubes a night from the surface. It's a dirty tank unfortunately. When I travel, that builds up.

For context, my skimmer exports a quart ot black water and thick sludge every day.

I have a chaeto refugium that I prune when I can, and I don't have any hair algae.

I also run GFO and carbon reactors. I've also use LaCl in the past.

I feed maybe 6 cubes a day and I add about 70ml of phyto every night.

I'm interested in this because I have a layer of persistent brown fuzzy algae against my highest rocks. It doesn't interfere with my coral but it's hard for my tangs, snails and crabs to get to.

Why the high flow? That's what passes from my tank to the sump. I don't want to add another pump.

Why the large size? I can only clean it monthly with any regularity.

I thought CFL was an ideal low cost light source. If not, I can use 48" fluorescents or LEDs. The LEDs need dedicated cooling and that can be a pain.

 

[SantaMonica]

Let's say we have an aquarium with a properly sized & productive ATS with your typical hair algae. Will the scrubber likely be beneficial in reducing or limiting the growth of other species of algae. For example the very different species like bubble algae & the various turf algaes?

Yes but they go away at different times. Dino's and diatoms go first, then gha, and lastly bubble, cyano and bryopsis.

Does this well tuned ATS typically starve & kill these more difficult species, or just slow down their growth?

It's all relative to import and export. If the scrubber is not enough to handle the import, then it's not well tuned. If it is well tuned, then it should slowly remove the tougher stuff.

For really tough cases, are any complimentary tactics useful like a lights out period etc.?

Any other filter that removes nutrients will help. Lights-out will usually not because it puts nutrients back into the water which can make the scrubber grow darker.

Is it feasible to build my ATS for a 6 cube per day system, but only rough up the screen for the portion of size equivalent to what my current feeding rate is? I.e. I will gradually increased the rough portion of the screen over the next couple years, while leaving the rest smooth.

No you don't want smooth screen. Instead just make several smaller scrubbers or screens, and start them up later.

2. Each sheet is 4ft wide x 2ft wide ( x 2 sheets ).

I travel a lot, so I need something that can go without cleaning for a long period of time.

Unfortunately waterfalls don't work this way. Once the first layers start growing, the new layers on top of them block the light and flow. Then the bottom layers die and put stuff (sometimes whole blocks of growth) back into the water. So the safe time to go is 14 days.

Upflows however, have been shown to go almost indefinitely without dying, because they are always swishing around underwater (they can't matt-down).

I'm interested in this because I have a layer of persistent brown fuzzy algae against my highest rocks. It doesn't interfere with my coral but it's hard for my tangs, snails and crabs to get to.

Just try regular sized first. If you can imagine extra handfuls of algae being exported, those nutrients have to come from somewhere.

 

[jason2459]

Past couple days my ORP has been climbing back up. This morning was the biggest jump hitting 396. Now to see if it gets back over 400 and stays in that 400-420 range. Then my theory is I'll have a nice thick ATS screen again in another week and a half. This will really solidify my thoughts that the Turbo ATS is directly effecting my ORP values and one of the best things I've ever done for my water quality. Plus it let me know there really is such a thing as to much flow.