Anyone have experience making bath bombs?

If anyone knows the answer to this, please tell me because I've tried a hundred combinations and nothing is quite right. I've been making bath bombs for a couple weeks now and I want to sell them. However, I want bright vibrant colors like Lush bombs, and when I use my powdered colorant the bomb turns a pretty color, but the bath water doesn't and it leaves a ring of color in the tub. When I use liquid, I can make the bath water a fun color and it doesn't stain, but if I use enough liquid to create a bright enough color then it messes up the bath bomb because it gets too wet. Does anyone at all have experience here?Picture is two bath bombs I finished last night.