Hello All,
The concept of an ATS is very attractive and, as the title suggests, I want to believe. It seems like these have gone through a variety of iterations since Dr. Adeys original work. There are a lot of assertions about them made on another site. the Super Moderator there makes a variety of claims that seem on their surface to be contradictory at times. I think Floyd and Bean have previously noted this.
The concept of exporting nutrients in this way is simple but it appears that the execution is not. I've done a bit of reading about them but I have questions that I can't find answers for or the answers I find need clarification.
The originals appear to be horizontal trays with a dump bucket. Some appear to still be using these but the other site simply dismisses these for their obvious problems - but I can;t find any reference to what these obvious problems are. One one car to illuminate?
The dump bucket was to produce turbulence and disturb the boundary layer between the water and the algae. The waterfall design presumably uses gravity and flow rate to attempt this. The new upflow version uses air bubbles from a cheap air pump. Perhaps the upflow version would work just as well with enough flow, turbulent or not, and no air bubbles? I cant see any meaningful gas exchange between the surface of the bubbles and the algae (as has been proposed), particularly if the water is already well oxygenated (and CO2ed) from a skimmer or overflow box. They could keep the algae from channelizing. In any case turbulence means microbubbles and salt creep. A solution with extravagant flow and minimal turbulence would be preferable.
Illumination with LEDs seems to be a very reasonable solution. Limiting the the spectrum to the most efficient red wavelengths is much easier to achieve with LEDs than more conventional lighting technology. Does anyone have long term experience with this?
Sizing the screen based on nutrient input seems much more logical than by tank size since the entire point is nutrient export. Lighting both sides is suggested to double efficiency but use of reflectors behind a scrubber lit from a single side seems unlikely to make a real difference once the screen starts to grow well. The "corner upflow scrubber" seems to violate a principle rule by placing the screen at a 45 degree angle to the light source. Most engineering issues are simply choices about where to make the compromises. Can screen size, flow rates, horizontal vs vertical issues all be traded off against each other to achieve the desired result?
It seems lighting intensity, spectrum, and, to some degree, duration would be limiting factors that would be difficult to compensate for. Or have I misstated the issue?
I believe that Floyd experienced some regression of LPS or soft coral after introduction of an ATS on his systems. Has anyone else observed this?
Some run skimmers with their ATS and some do not. It seems that a properly functioning system would allow one to run a smaller skimmer or perhaps one of the "plankton friendly" horizontal centrifugal skimmers. Does anyone have a thought on ATS only or sizing a skimmer on a system with an ATS?
Thanks for the patience.Mc
Patience is easy with well written question(s).
You ask very good questions. I read Adey's book the week it came out and could see little to not embrace in it. I've been messing with ATSs for years. On that other site I may still have the longest thread. It meanders through several iterations of an ATS I built that morphed from vertical to horizontal, LED to CFL and back again.
Where I believe the difficulty lies is with the large set (and I mean that in mathematical sense) of variables in the space.
You have the:
nutrient load
nutrient types
algae species
available
growing surface area
growing surface texture
temperature
temperature rate of change
light intensity
light periods
light frequencies
light distribution
cleaning frequency
dissolved gases mix
water flow rate
water flow profile
screen angle
screen angle to flow
and those are just what I can think of off the top of my head. All of those have an impact on how well your ATS will grow and sometimes more importantly, initiate.
All the numbers for flow and light amounts and cleaning frequency are really just guidelines that have proven to work over several ATS builds. They're a good place to start. Your mileage will most likely vary.
One important point is that when you add food, light, and CO2, something in a rich ecosystem will likely be able to take advantage and run with it.
ATS unlike most skimmers can be pretty inexpensive so the barrier to try one is pretty low. So low, that only taking the time is often the hardest part.
Most any ATS you can imagine will work. Horizontal, bubble-up, vertical, two sided, one sided, dumping, surging, burping, upflow, downflows, etc. they will all work as long as the light, flow, and nutrients allow it.
If you see the one I'm working around, in the top of the DIY forum right now, you'll see I have a horizontal single sided one. One side is red LEDs the other cr@py end-of-life CFLs. Both halves grow the same amount, (a lot), of algae. If I look closely they look slightly different but the gross aspects are too close to matter.
So build whatever style your physical setup will work with, follow the screen sizing and light rules of thumb and give it a try. Don't hesitate because 'this week's' version isn't a good fit for your system.
