UAS question

[cfortin]

Okay I am very intrigued with this new design. It takes up way less space, less light/ energy, and enables me to not suspend a light over the water n my sump. This might be long winded, hopefully u can help. I have an algae scrubber (waterfall) type that has been running for about eight months, my algae has gone way down but not completely gone, I am still runnin a PS, I'm sure this is not right, just scared to transition. I like this new idea of the air bubble scrubber. How can it be so much smaller. I have a 100 gallon saltwater coral/ fish tank, 30g sump. I have two aqua illumination set ups running lighting on my tank. I still get algae up top close to light source, that is another story. Can I really get away with just one of your units, and no PS or anything else, seems small, I do feed about 2 cubes, every three days. Maybe this is the issue. Really interested, please let me know, if I need to change anything or if I can do the switch over

[Floyd R Turbo]

IMO, the UAS is still in the "experimental" or "alternative" stage. There certainly hasn't been enough long-term data to warrant solidifying it's effectiveness. I have a 120 sumpless tank with a large Sailfin Tang, medium Yellow Tang, 4 beefy chromis, and a mixture of corals (which includes one 20" tall 20" round elephant ear leather) and I had been feeding them about 2 cubes/day. I run a top-of-tank double-sided 4x6 screen with 6 660nm red LEDs and one 455nm blue LED on each side. The screen gets pretty good growth every week, but if you read my recent posts you would see that I went from N=0 P=0 back in April when I put the UAS on to now N=25ish P=0.23, and that's after a 45% PWC and cutting feeding back to 2 cubes every other day and upping the scrubber light cycle to 20 hours/day for the last 2 weeks, as well as increasing the flow to the UAS and doing a few other mods.

I guess I should also say that while I feel my UAS is pretty powerful as far as light and growth goes, I am somewhat limited by the amount of flow I can push through it because of microbubbles dumping back into the display. I may try to fix this next to get better flow across the screen.

So while the current "guideline" for screen sizing based on feeding (maybe you aren't using this now??) is 12 sq in per cube of food per day with 12W total (fluorescent) light (split between each side) work very well for waterfall type scrubbers, is has been proven many times to be accurate, I cannot say with confidence that the same rule applies for the UAS.

So if you're feeding 3 cubes every other day, on average that breaks down to 1.5 cubes/day and you should be able use an 18 sq in screen with 9W of light on each side, assuming flow is proper and screen is rough enough, etc etc. That's for a waterfall scrubber, and lit on both sides.

For a UAS, which are usually one-sided due to the nature of the thing (and it's not as much of a problem for a UAS to be single-sided like it is for waterfall) then you would need it to be at least 36 sq in, with all 18W of light on one side, in order to handle the amount of feeding you are doing.

For me, flow past the screen is the biggest issue, others may not have quite so much due to configuration, but like I said it's still sort of experimental. Think about it in terms of the waterfall scrubber, if you have a 10" wide screen, you need 350 GPH across that screen with a waterfall. You should strive to have a similar flow rate across a UAS screen, and while at this point there isn't really a measure of water flow across a UAS screen (mainly because it's difficult to measure water flow inside the tank), just air/bubble rates, I believe this is a factor to be considered.

So if you look at all of this and see the UAS as the better alternative between the two, all thing considered, they give it a try. My suggestion on your setup would be to either use the existing screen you are using as much as possible, and if you need additional screen just rough up another one, just make sure you have enough or more than enough growth area considering the single-sided issue.

The other alternative would be to set up your UAS separately, leaving your waterfall scrubber to continue to run as-is, and let your UAS screen get some growth on it (give it a good solid month). Then start lowering the hours of light on the waterfall scrubber and increasing on the UAS until the UAS is growing sufficiently and consistently, and your N and P are in line, then you can take the waterfall scrubber off completely. This way if you feel you are having to tweak and modify you UAS setup, you can do so without risking any livestock loss due to inadequate filtration.

As far as your skimmer goes, IMO they're fine to run in conjunction, but I would consider putting it on a timer and running it for a limited number of hours/day, say a couple of hours, overnight. This way the food you feed will get more of a chance to circulate and be used by all organisms in the system. There's nothing wrong with relying on multiple forms of filtration.

Ok so there's a book for you - sorry that got long

Hope it helps

[SantaMonica]

I am somewhat limited by the amount of [air] flow I can push through it because of microbubbles dumping back into the display.

And air, of course, if the driving factor in a UAS.

(and it's not as much of a problem for a UAS to be single-sided like it is for waterfall)

It actually is. 1-sided causes the roots to dies twice as quick, and let go twice as quick, which will not let it hold on to long GHA, which is what filters the most.

and while at this point there isn't really a measure of water flow across a UAS screen

Water flow in a UAS is not a factor, as long as the growth gets the proper nutrients. Water flow in a waterfall is just a technique to deliver nutrients. In a UAS, air controls the delivery of nutrients, and dwell time controls the ambient nutrient level.

Cfortin is still having a nuisance algae problem, however, even with his current waterfall scrubber. So there might be some other factors.

[Floyd R Turbo]

It actually is. 1-sided causes the roots to dies twice as quick, and let go twice as quick, which will not let it hold on to long GHA, which is what filters the most.

I haven't tried running a single-sided UAS myself, but it just seems to me that with the screen immersed that there is less chance of the algae letting go since the bubbles and water flow allow light to penetrate deeper into the screen, similar to how 3D growth in a waterfall scrubber allows a similar situation. At least that's what makes sense to me.

Water flow in a UAS is not a factor, as long as the growth gets the proper nutrients. Water flow in a waterfall is just a technique to deliver nutrients. In a UAS, air controls the delivery of nutrients, and dwell time controls the ambient nutrient level.

I would challenge this statement. Take it to the extreme - if you have extremely low water flow past the screen, then you end up with a lot of dwell time but very little turnover, meaning that in a large system, you have a lot of water in the system that does not frequently pass by the screen and get "cleaned". Conversely, if you have a high turnover, you would get less dwell time but a higher rate of available nutrients. In the latter case, you can increase the lighting intensity and/or duration and get better filtering, whereas with the former, increasing intensity/duration will only benefit you to a certain point - the nutrients can only be taken up at the rate at which they are provided.

Cfortin is still having a nuisance algae problem, however, even with his current waterfall scrubber. So there might be some other factors.

Agreed, there is likely a problem with his current watefall, but without seeing it there's no way to know what that is - Cfortin, got any pics?

[Garf]

Cfortin - as Floyd said, pics would be good with all the other info such as light power, distance from screen, light replacement schedule, flow, screen cleaning schedule ( basically as much info as you can detail ).

[cfortin]

Okay, sorry it took so long. I have a 10 X 10 screen with appropriate pump. I have it two sided with CFL bulbs 2700k either 23/ or 32 watt. ( sorry I forget). Attached are the pics of the scrubber. Let me know what you all think, if I can improve anything. What you see is pretty much the color of the growth I am getting but more of it. I dont know how you guys are getting that bright green. Love to know though. Keep me posted. Thanks for the help!!!!!

[kerry]

You need more light, you are only running about half of what you need to run. Your screen is 10x10 so that 100 inches so you need 100 watts, 50 each side.

An example VERTICAL waterfall screen size is 3 X 4 inches = 12 square inches of screen (7.5 X 10 cm = 75 sq cm) with a total of 12 real watts (not equivalent) of fluorescent light for 18 hours a day. If all 12 watts are on one side, it is a 1-sided screen. If 6 watts are on each side, it is a 2-sided screen, but the total is still 12 watts for 18 hours a day. This screen size and wattage should be able to handle the following amounts of daily feeding:

[Garf]

More light and closer if possible. I take it you haven't replaced the bulbs for a while considering you can't remember the wattage. Cfl's require replacing every 3 months if used for 18hrs a day.

[Floyd R Turbo]

That's a good setup overall. I particularly like the gray PVC light blocker sleeve pipe.

+1 to the previous 2 responses. If you drape the screen in saran wrap, you will be able to move the lights closer without getting salt creep all over them. If you have 23W, bump them up to 32W, and if you can, go to 40W+ ($$). That's if you want to keep that setup.

Personally I would consider downsizing the screen at least to match the lamps. So you have 46-62W of lighting, scale it back to 7x7=49 or 4 cubes/day, that will get you in a better range. If you tank has been set up for a long time, there might still be N and P leeching out of the rocks, which could overpower a screen sized for what you feed now. That situation won't last forever, so you might get some nice green growth for a while then it will slowly shift to yellow as the nutrients dry up. When you're to that point, you can scale the screen back more.

If you're only feeding 2 cubes/day an not every day, and that were the only factor, then I would do no larger than 6x6 and light it with CFL floodlights (23W each, 2700K, built-in reflector). You could probably do that now and be safe also.