Lowering a high water level to reduce plant height isn't a bad idea. If the roots are dependent on that water, meaning that they are growing in it, and you have mixed fert in the water, you have to be careful because usually as a plant grows you use more fert and perhaps more water due to uptake and evaporation. I'm guessing that some light will get in the aquarium, which will cause algae to grow but it might not be too bad. Just never heard of growing like this. You want your water to be completely hidden from light to avoid algae, but you might be able to make it work. Frankly, I think it might be better to spend a few bucks on a DWC bucket. Are you planning on using fert poop as fert? Why not just grow in soil?