@SkyDog like @Craigson15 mentioned blumats are an excellent option and will work for any size container, look into them 
myself i have a timer based system currently and run coco but my container sizes are all the same and i collect excess run off.
@SkyDog like @Craigson15 mentioned blumats are an excellent option and will work for any size container, look into them 
myself i have a timer based system currently and run coco but my container sizes are all the same and i collect excess run off.