UAS possible without bubbles?

[Igel]

Hi there,

I was wondering whether it is possible to eliminate the bubbling sound from my UAS (HOG 3). Could I possibly replace the air bubbles by a circulation pump? For that I would increase the in- and outlet of the HOG 3 in order to achieve sufficient flow. Since the UAS is in the same section of the sump with a simmer water should be saturated with oxygen and carbon dioxide. Does anyone have tried this out before or is running a UAS / submerged ATS like that?

Thanks ahead and best regards from Germany

[SantaMonica]

HOG scrubbers are not really designed for "silent" operation like the SURF scrubbers are, however you can try these things to make a HOG scrubber more quiet:


1. Move the HOG up and down on the glass; usually putting the top 1" of the HOG above the waterline will help.
2. Reduce air bubbles; if pump is not adjustable, then pinch the air line with a paper clip or a knot.
3. If the HOG must be below the water line, then attach air line to the top hole so air can come out above the water line.

Reducing air certainly works, but it reduces filtering too. If you must reduce air, then you could also try automating the air level by using two pumps and having one of them on a timer: One pump on at night (for quiet), and both on during the day (for most filtering). Just connect both pumps to a "T" so they both feed into the HOG air tubing.

Upflow scrubbers like the HOG must have air bubbles, however, or they will not grow much at all:

http://www.algaescrubber.net/WhyBubbles.jpg

[mattberrytr]

Do you have any scientific papers to back this up SM? This doesn't make sense to me. I can't see how the surface tension of the bubble would allow the 'inside' of the bubble to become exposed to the algae. The bubbles will simply move out of the way, or if there's enough of them, move the algae strand(s) out of the way.

[SantaMonica]

Well if you want to start reading about photobioreactors, you'll find plenty. Or Dynamic Aquaria.

[mattberrytr]

I'm not referring to water absorbing co2 from a bubble, I'm referring to your image stating that the algae strands come in direct contact with the 'inside' of the bubble.
If you could point me to studies that support that, I'd appreciate it.

[Crusinjimbo]

My ATS is horizontal with about a 20 degree slope to the drain. It sits on top and perpendicular to the sump. The water feeds via a Rio 600 pump to a 1/2" PVC pipe drilled with 10 1/8" holes shooting water on the top edge of a 5" wide by 14" long screen. Lighting is by 3 each 9 watt (8 1w 660 & 1 1w 440) 12" strips suspended about 3" above the screen. Smooth water flow accross the screen, no visible bubbles but a moderate turbulence in the water sheet. My algae mat. On the seventh day I have a 100-140 gram (squeezed) harvest. The mat of algae is thick, green and 1/8-1/4" thick. No bubbles. No noise, salt spray, plastic wrap curtains and no NO3. I can argue with bubbles producing possibly greater growth levels but I know for a fact that big bubbles aren't required for good algae growth. I figure it is like my car, it has 400 hp but I don't think I have ever needed them all to get where I want to go.

[SantaMonica]

Waterfall and horizontal rivers are like a giant air bubble. The entire side of the screen is covered in air/water turbulence. So that make the point, that air/water interface turbulence is necessary for rapid growth.

If you want to see that NO air would do, put the entire horizontal screen at the bottom of the sump, under 6 inches of water. Or at the bottom of your display.

[mattberrytr]

That may be true to a degree for waterfall scrubbers, but it's certainly not always the case for horizontal or slanted scrubbers.

I believe the reason why waterfall scrubbers are so effective is because of the small boundary layer created by very fast water flow over the algae. This allows for high nutrient transfer between the water and the algae. I'm not saying the air/water interface is not beneficial, but I think its influence on algae growth has been exaggerated.

Of course algae will not grow well under 6 inches of water, because the flow would generally be low or non existant. It's been proved numerous times that submerged scrubbers will grow algae well providing there's decent flow. If you don't have decent flow through your scrubber (which allows for high nutrient transfer) you will not have an effective algae scrubber. Sure you'll get some growth, but up the flow and you'll get a tonne more.

[Paul Vingerhoets]

Hello have you got any photos on this setup ?

[Crusinjimbo]

Yes, I see the turbulence factor, similar to the tank water surface exchange process. Anyway, here is my current prototype. An ATS is a tinkerers dream!
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[Crusinjimbo]

The lights are three 9w strips fro Expressions LTD. The white plastic screen tray and light holder are silverware trays from Wally World.
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