In preparation for putting the acros I got from the swap into my tank, I picked up a Vortech MP10 today to give me some variable flow. My thought was to replace one of my two Koralia 2s in my stretch hex 40g with it. I mounted it and turned it up to max to adjust for vibration and was stunned at the flow. It kicked up a ton of detritus and sediment and I could feel a strong current coming out of it with my hand. With the same test, I could barely feel any current out of the other Koralia 2. I've now removed both K2s and am waiting for all the detritus and sediment to die down. Very happy owner here.