Timbits

Hey guys, so I have a BCNL grow box. Small Rez(4gal) with 400w cob LED's. Have a cpl of nearly successful grows. I'll admit i do better in dirt. I'm noticing a trend with every grow in this box at the very beginning. I get this white goo building on my airstones and water pumps. I'm pretty confident it's sterile at the start and my water is tap but may as well be bottled. Soft clean water. I always neglect to cover these light leaks and everytime this happens. Just curious if I'm overthinking that the bit of light that gets in can do this. So forums have said I'm overthinking and to play it out.. but this is the very beginning and I just can't believe that the plants would thrive with this goo in there. 2 days ago my Rez look as spotless. Taproot popped and I but nutes in and boom 24 hrs later this?? I cleaned the system top to bottom. Bleached the lines two times for 60 minutes total and rinsed for the same with fresh h2o. Now I have 5 gallons in there with 15ml of 30% h202. Also went above and beyond not letting any light in. Like none now. Going to put nutes in tmrw, but wondering if I'm on the right track? Drives me crazy how quick it changes. Took a pic off the goo in question.