Hello,
I was looking to buy a used Tunze 6100 or Koralia 4 if anyone had any they wanted to get rid of. I have two Koralia 3, and they are doing a decent job but it doesn't seem like it is pushing enough water to really reach the other side of my tank. My tank is 7 ft long so it has a long way to travel. If anyone would like to trade a Koralia 3 for a 4 plus compensation, please let me know. If anyone has any additional suggestions, please let me know.