I have the same problem, I don't like the look of red, I have blue mixed in my substrate from when I was into cichlids, but it's mainly black, I'd say mix in red with whatever you want, I'd do it if I could do it over again to give it a try. I for one don't think substrate color will change activity, I think that's is a specimen thing, my weeksii and sen never stop swimming up and down and side to side, my delhezi swims all over the place at feeding time, the rest stay at the bottom, my ornate has just come out of hiding and has been out for two weeks straight, don't know what caused that, maybe she's finally comfortable even though I've had her over a year. I like the look of my wolf over the black and that's my main focus, and it also brings out the colors in my odoe pike, and makes my sun cat's yellow pop. I'm satisfied with my UJ colors. But I feel my laps can do better, I'm satisfied with my male, but my female is sometimes very drab, i thought about getting rid of her to reduce some bio load and because I don't like having more than one of a species, but I don't want the male to get anal cupping I believe it's called, so I still have her.