Hmmm... I'll try this.Photo for reference
See two dots are lined that is full open and telescope pipe all way down and you can try slow wattage from 38, let it run few days if too dry not skimmate maybe up to 40w
Also make sure nothing clog your air inlet and silencer.
water outlet also need be to above water level. Make sure it not full submerged.
I never heard the outlet pipe was supposed to be above water level.
Thanks!