You could tint it using a couple of methods. Either pickup a gallon or two of new sealer that is tinted more towards the color you are seeking (clear for a thinned down redwood color or a brown to tone down the reddish color and make it more rich) Option two is to go toa paint store and purchase universal pigmentation and add drops of black to achieve the same richening effect.

It takes very little black pigment to make a stain brown. Mix all of your sealer together then add the pigment in drops and stir well to determine your color. My preference would be for you to mix factory colors.