OK, good news for me. the skimmer is back to normal. just back from work and saw the bubble is lower to below normal.....
oh, i never know i need to only submerge the skimmer to half of the boddy only. Thanks alot. will try to raise it.
already turn the tube to the max when it happen, also check for strange thing that can stuck in the tube but nothing.
Is this normal in all skimmer or only the brand BM?
anyway Thanks for all the advise from all the bro and pro.