Skimmer performs great. Simple, easy to install in a sump. Easy to adjust and regulate. Works best with a constant sump water level. High-quality materials and excellent construction. I always look for simplicity, and this skimmer fills that bill while performing great. I use it in my 75-gal tank and the skimmed waste is dark brown/green. My ORP is consistently greater than 350 since using the skimmer, while before it was around 300.