Bubble Magnus 7
 

Can you help me w adjusting. It’s in my sump and I have it only a few inches deep, but it still overflows. I’m not sure what else to adjust besides the flow knob and it’s turned all the way down.

Ive owned it a few months and it previously was working but I’ve always had to turn it way down.

Bubble magus
 

Ugh, im getting pretty frustrated with my BM5 also. Its very eratic and does whatever it wants. When i got it i did a vinegar bath overnight put it in the sump on lowest water level, it eventually broke in and was working great i had to keep adjusting the water level higher and higher over 6months. It was at highest water level and not skimming. I pulled it all apart toothbrush ect, then a vinegar bath. I put it back in the sump and it took 3 days to start producing skim again.

I would like to hear from someone who has had good success with a BM.

Do you have a filter sock before the skimmer?

Sock
 

No sock. It sucks water direct from sump. My thinking is to get particulates out w the skimmate.

I have done hrs of searching for an answer and from what I have seen the people who say there BM skimmer works perfect have a pre filter sock before the skimmer. I have included a sock in my new 90G build so I will be using the same skimmer and will see the difference. It looks like now whats happening is there is just too much junk that gets stuck in the pump and skimmer neck and hinders performance over time.
Most people report 8 1/2" water is perfect for the BM skims. Just pull the drain hose plug and valve full open and letter buck for a few days till it calms down.

was this a new tank when you added the new skimmer?

I don't know what kind of setup your sump is but if you can stick a sock in there somehow I think you will see a difference. I will have my setup cycled and running in a few months and will report back.

I have a 7 and 10" of water works perfect

Do you have a filter sock? How often do you tear it down and clean?

No. Its a 400gal FOWLER with only a huge Miniatus grouper and lots of mushrooms that grow like crazy under VHO lamps. Techniquely not a FOWLER, but anyway... The system is 13 years old. I bought the BM 6 months ago and had a hard time adjusting then There seems to be an air inlet that might be adjustable...but I haven't figured that out. I finally got it to a depth of 4 inches and stopped the overflowing, but after a water change a few weeks ago, I can't keep it from flowing like crazy. I'll try your suggestion, much thanks.

no sock ... clean it once the riser starts getting coated with gunk maybe every cpl weeks

Check the venturi part on the pump where the hose connects. Make sure there are no calcification on it and clear of debris on the air side. Also as Bucaneer stated between 7"-10" of water is best. You might have to make a stand for it if water is too deep. Any deeper it starts to over flow in mine. I have a NAC9

Post a picture of your skimmer it might be missing something if it is second hand

the fix
 

I got a used BM7 for my 90 gallon, did a vinegar bath scrubbed it clean. After putting in the the sump with dial on "max" it began to overflow right away. Did some more googling and found that a drop of fish oil in the skimmer neck was the cure. sure enough put 1 drop omega 3 fish oil and the bubbles dropped immediately ,over the next 12 hrs the bubbles slowly rise and then start to produce skimmate.

Still fully open dial "max" and producing good skim as the skimmer gets dirty slowly close the dial so it keeps producing good skim.

Currently In 10 3/8" deep water