Irregular Plant growth?

so i have four plants placed in an even square on my hydro kit with the lights directly in the center of the kit, red light in back blue in front if that matters. i have noticed over time that the one on the front right has grown MONSTROUS over time, the one in the front left has shown normal growth, and the two in back are growing INSANELY slow, almost half the siz of the ones in front. any suggestions as to what this might be and how to correct the growth patterns? any advice is much appreciated considering im still a noob sadly, this is my first kit .

The front is soaking up the blue spectrum bulb which are good for veg and is causing it to shoot like that. May look taller but the bud will become more fluffy. I'm guessing your using t5 or floros. You should switch the bulbs back and forth to get a more even canopy