Sorry this is so long, but here is the way to ge around the gray-blue but still keep the feel you seemed to be going for.
For a traditional looking colourwash with great open time-
In an empty gallon paint bucket - a diluted mixture of:
2/3 bucket matte clear acrylic glaze
1/3 or thereabouts plain water (add 1/8 cup or less water to the bucket at a time - mixing constantly, till it is a medium-thin lotion-like consistency on your fingertips.)
small bottle of acrylic paint 2-4 shades paler color than the wall. (I don't recommend stark white here, since you mentioned using blue-gray it will look like you tried to "fix a mistake" - do one of the the lighter shades...once it is on the base paint, it will be less stark)
Do a small test patch in a unnoticeable spot...keep a damp rag nearby - it will wash off.
Drizzle and mix in your lighter color - just a little bit at a time.
(this should be mixed to be the paint world equivalent of the LIPGLOSS to Lipstick ratio of sheerness)
If doing a larger space than a small bathroom, this recipe doubles and triples well. Just be sure to mix ALL the CW liquid at one time so it will all be the same intensity.
I have done this colourwash for countless clients and it works every single time! <img src="/images/graemlins/grin.gif" alt="" />
This will give you a MUCH more workable surface, and if you usually work slowly, will give you much more open time than the plain paint/water colour washing liquid recipes usually available.
I urge you to try using a natural bristle, 3 inch wide chip brush - super cheap at Lowes or Home Depot but fantastic for this very job, is lightweight and easier to control than heavier glazing brushes or unwieldy sponges. These brushes give you the instant cloudiness of colourwash and keeping the damp sponge in the free hand, you can use it to smooth and cloud the glaze to acheive the colour washing "seamless" feel.
It is practically impossible to achieve a true color wash working with only a seasponge.
Also, using the sponge, if you don't do this work every day, it is VERY difficult to achieve an even coverage and texture in working out your corners...nothing is worse than a DIY finish that looks great on the broad walls, but gets mudddled in the corners. That is the difference between pro-finishes and obvious DIY walls. You want a colourwash - not "sponged" walls. <img src="/images/graemlins/tongue.gif" alt="" />
Use more glaze in your recipe for more open time.
More water for faster drying...
Please note: If you use the same base paint color, diluted with water, you are NOT changing the color tint- only diluting the opacity of the paint and making IT sheer...you won't see much, IF ANY color difference at all.
Here's to Beautiful Walls and Easy Finishes! <img src="/images/graemlins/rolling.gif" alt="" />