Dumb question of the week . . . water outlet tube on Bubble Magus

[houstonhobby]

Everyone,

I got a Bubble Magus NAC 77 and have been using it for a while. When I first got it I noticed it had a tube at the back labeled with numbers, plus "Max" and "Off". I had no idea what the tube did, and the papers that came with it did not mention it.

I set it to "MAX" during setup. Then I forgot it was there. I thought of the skimmer as something that was adjusted by moving it up and down in the water column. There are thumb screws at each corner for this purpose, though the total range of movement is less than an inch.

So today I thought I would try water change via wet skimming, so I needed to make the skimmer output a lot of skimmate in a short time. I thought raising the water level would do that, but it wasn't doing it for me. I have seen this thing pump water into the cup at gallons per minute, and the cup has a tube attached, so I was expecting an easy time.

But, no wet skimmate. Not even when I essentially lowered the skimmer into the water up to the bottom of the cup.

I had completely forgotten about the tube at the back (which all Bubble Magus have, but whose whys and wherefores no Bubble Magus manual explains) but I figured out today that if I set it to "Off" I will get gallons of wet skimmate. In minutes. Be ready to swap out 5 gallon buckets every 30 seconds. At "Max", no skimmate. Somewhere between "2" and "3" seems to be the sweet spot for this.

But, I still don't really understand what this adjustment is doing and why, and if somebody out there does understand it, I would really appreciate an explanation.

My best guess is that it is closing off water in the barrel of the skimmer or letting it flow (in? out?) with the sump. But I don't have a good understanding of why that changes how much skimmate I get.

Thanks,
Rod

[Crusinjimbo]

The tube is cut at an angle where it enters the skimmer base. Twisting the tube between MAX and OFF restricts the barrel outflow causing the foam head to rise higher in the barrel and collection cup. I crank the tube closed enough to hold the top of the foam head to a wet or dry height. BM directions are primitive to say the least.

[Icefyres]

What he said basically you adjust the outflow from the skimmer. BM has some extra ordinary crap manuals but good skimmers. I Used to have mine on 4 but I can't remember the depth (was some time ago)

[houstonhobby]

Thanks everyone. Knowing this I find I can now get coffee colored skimmate without adjusting the skimmer water depth, which was much more of a pain than twisting the tube.

[fiestazs90150]

i have a nac 7 cone. works great BTW.

as said the tube is too adjust the amount of water going out of your skimmer exit at any given time. Therefor adjusting the level of water in your skimmer.

the thumbscrews on each corner arent there for adjusting the height of the skimmer, they are there to take appart the skimmer when you need to clean it.

mines in 26cm water depth and on like 2

[billy mitchell]

I have BM200P and recommended water height is 9-11" after running set the tube to have bubbles inside canister tube to halfway and then readjust to either wet or dry skim
they are good skimmers