I agree with the salt thing, too.

But please don't do what I did and follow the directions on the package of RIT dye. It says to add dish washing detergent, about one or two teaspoons.

I couldn't get my canopy to take the dye so I added a pair of air stones hooked them to an air pump and put them in the bottom of the bucket for agitation and and left for lunch.

Holy cow, what a mess I had when I got back. With the soap and the air stones I had black dye everywhere. The head of black foam was as big as a Buick.

Ended up just spraying the canopy. ***Sigh***