[Alex T.]

I bought a slightly used (less than a month old) Supermarin 200 back in February, cleaned it in white vinegar and RO water and plugged it in 3 days ago as my new 195 gallon tank is cycling. It's sitting in 8" of constant water level as suggested (20-25cm) and will not stop overflowing. I have the drain line 100% open and the red pump nozzle all the way closed, but it will not stop. I took the silencer apart and cleaned it, checked that there are no obstructions in the drain line but the problem persists. All my rock and sand is dead from being bleached and cured in muriatic acid 4 months ago and thoroughly dried, and as a precaution I started all new water with Seachem's Prime to rid the rocks of any residue. There are some orange plastic pieces in the airline (I assume they're there for a purpose but who) that don't seem to obstruct the airflow.

Every other skimmer I ever owned could be tuned to allow less water in and not overflow as it breaks in. With the drain pipe open and the pump all the way closed shouldn't this be the case? I'm confused.

Any help would be appreciated.