Hi Antolo, I have the same tank and similar skimmer as you (i.e. the Reeftek BH100). I have had similar problems. Try raising the water level in your tank to the red line indicated by Juwel. I find my Reeftek skimmer is very sensitive to water height (although I have the in-sump pump).
Also try adding another piece foam to the last chamber in the skimmer to help reduce the bubbles before entering the tank.
If all else fails, twist the outlet pipe so that it lies on the water surface level. This way the bubbles exit at the surface level and do not enter the tank as much.
Also try adding another piece foam to the last chamber in the skimmer to help reduce the bubbles before entering the tank.
If all else fails, twist the outlet pipe so that it lies on the water surface level. This way the bubbles exit at the surface level and do not enter the tank as much.