If you have to clean your caps/tanks try a little Milton Sterilizing fluid, used for cleaning babys bottles.
With a baby due at any minute, Tomo will have plenty of Milton about.
I've not had problems with my barrels, since I work hard and the barrels are kept moving, sloshing water about; therefore preventing any algae from growing.
If Tomo pulled his finger out a bit and did some work for a change, algae growing in his barells wouldn't be a problem, nor would spiders making cobwebs in his brush head.