try this for your cups instead of tape.
get some blue or red cups, the same size as the cups you have now. and just set the clear cup inside of the other, to act as a sleeve. then you can check them easily and block out the light at the same time. dont forget to cut slits out of the bottoms for drainage.
get some blue or red cups, the same size as the cups you have now. and just set the clear cup inside of the other, to act as a sleeve. then you can check them easily and block out the light at the same time. dont forget to cut slits out of the bottoms for drainage.