Hey John. While I don't really know much of anything about clams, I think one of two things is going to happen or needs to. 1) the clam will adjust itself until it finds the light/flow it likes--I'm assuming the Maxima's are like a bunch of other bivalves and can be mobile. 2) it will start to decline due to not enough light and you will have to adjust it. Unless someone else chimes in, I say let it sit for a week or so and see how it reacts. I would think you could tell by then.