I started out with all black buckets, had no problems for over a year. I switched to blue buckets and a self watering system and I used semi clear blue lines to feed the buckets. Needless to say I have been dealing with root rot for about 6 months. I have changed out all my lines to black and will do the same with my buckets. I have algae inside my buckets, but it doesn't grow where the white lowes paint is. Clearly light is getting in where the paint isn't. The algae could have gotten in from my water lines but I still am replacing the buckets because I need to rid my system of any flaws. Do I believe others have used the blue buckets with no problems? Yes, but why not spend an extra dollar a bucket and get black that you know are light proof. Home depot carries black buckets now for $4 each. I don' want to take the time to cover my buckets since I know that will be a pain and it will be a pain cleaning them also. My advise is buy black buckets or you may end up dealing with root rot. I could have bought 50,000 black buckets with the money I have lost to root rot.
I paint my rooms with flat white paint and use 1000w hortilux bulbs. Someone who doesn' have problems may not be using 1000w bulbs or doesn't paint their room. Temperature is another variable, just because the blue buckets work for one guy doesn' mean they will work for the next. Not to mention what are you going to save? $20 ? Penny wise and dollar stupid is what I call my venture into blue lowes buckets.