First ATS is live - did I do it right?

[DWIZUM]

My first-ever ATS is live. I'm so proud. :D It was really easy. Almost TOO easy.

It's a conventional design - double plastic canvas panels vertically hung from a slot in a 1" PVC pipe, illuminated by CFLs (note there are reflectos on the CFLs that are removed in the photos below - otherwise they'd obscure the screen).

Anyways, I'm not sure if it's running correctly. Here are some photos:

http://i2.photobucket.com/albums/y30/derwillezurmacht/360g065.jpg

And a close-up:

http://i2.photobucket.com/albums/y30/derwillezurmacht/360g066.jpg

I'm not sure the flow rate is correct - it looks a little uneven, in the sense that there are rivulets on the "surface" of the screens in some areas, but water is only "between" the screens in other areas. I arrived at this flow rate by basically valving down the water supply to the TS until water stopped spraying out erratically and/or splashing too much. Does this look correct? It doesn't seem like a lot of flow to me, but then again I'm not an expert on these things.

FYI the shutter speed on my camera was really high for those photos so it makes the flow look worse than it really is. It's just not an even sheet over the screens. If I press them together with my fingers, the water is flowing fast enough that my fingers are instantly covered with rivulets.

If the flow rate doesn't look right, how do I increase it without causing excessive splashing? Is my slot too narrow or too wide? How do you know if it's right? I made the slot by taking two passes on a table saw, it's probably just under 1/8". The doubled-up panel is definitely not a tight fit, but there is a little friction when inserting it into the slot.

For reference, the pump is a Reeflo Dart, acting as the main return pump; the TS is T'd off from the main return line. The TS has been running for literally an hour, so obviously no growth yet. . .

[Crisis]

This is nice, I just posted a thread having the ATS connected to the overflow, but having it connected to the return pipe & T'd off with valve is another option. Looks Good! Keep us posted on the results!

[DWIZUM]

Found this image elsewhere:

http://www.radio-media.com/fish/UserZennzzoOnMFK-05.jpg

I don't think I have QUITE that much flow, but if I turn the flow up, I get spraying/dripping in large noisy rivulets, not an even sheet all the way across. Does this indicate an error in my build? Incorrect slot width or some other problem?

[SantaMonica]

Should be ok.

[new2scrub]

that looks a lot like my scrubber,,,you must also be an electrician lol

[DWIZUM]

Santamonica,

I played with it a bit last night and I can get a pretty wide range of flow, but it's not even across the screen - I get rivulets of water, between which there are patches of screen that are relatively dry. Should I let it go and hope it evens out once things start growing? Should I drop down to a single screen? Or play with the slot size?

new2scrub - actually IT!

[SantaMonica]

Let it grow

[DWIZUM]

So it's been live for a little less than a week. There's a good coverage of dark brown growth. FWIW this is a brand new tank, lightly loaded.

An interesting observation: I left the screens pretty long, so there's about 2.5" of screen below water level in the sump. The part below water level is growing in better than the part above water.

This makes me wonder - why do we have the screens hanging in midair? Why not submerse them? This would reduce the evaporation impact and it would be easier to tune them to run silently (mine is nearly silent but makes a gentle trickling noise I can't get rid of). I have a HUGE return pump and LOTS of flow in the sump, so if the reason for hanging them in the air is to get high flow velocities, I've got that covered "under water" in my sump. . .

[SantaMonica]

They are not really growing more there, it just looks like it because it's fluffed up.

[DWIZUM]

I don't mean to disagree, but there is clearly more growth on the submerged part of the screen. It's thicker, darker, and much more even in terms of coverage, both on the outsides of the screens and between them.

I'm wondering what factors are contributing to this. So far, this is what I can come up with. Firstly, my sump is highly reflective (it's white, as opposed to clear glass/acrylic or black acrylic) which means there's probably more light down underwater than on others' scrubbers. Secondly, I have A LOT of flow in the sump. The Dart is running flat out against a pretty small head, so there's probably around 3,000 - 3,200gph running through a relatively narrow/shallow sump.

Again, not trying to disagree or buck the status quo, just trying to understand what's going on.

[ocean rock]

how rough is that screen ,?
clean the black slime off?
you should see the green soon keep at it dont worry too much .

[DWIZUM]

I used a holesaw to rough up the screen until my arms were sore. There's a fair amount of cactus-like "fuzz" protruding from it. I'm not terribly worried at this point, since it's barely a week old on an understocked, relatively clean, brand new tank. . .