take price as the second thing, have you found we recommend our Mars Pro series very less? it has strong functions, remote control, control different spectrum separately , timer, humidity test,etc, a lot useful functions build in, as we think that that is best light and customers will like it. but the truth is , too many functions controlled by procedure , it will get problem easily and customers can not handle it, our repair center can not handle it . Any problem, we have to get it ship back to China, that is the biggest problem our customers will get. K3 or K5, they are remote control I have heard the same problem, lights are out of control, it will not do what you want them to. plants will be not happy. so I do not think K3 is a great light to choice . besides, you want to save money, if you buy their light, you can not save money, very expensive. they are made in China too, not worth to pay more.