no experience with them mate but a question comes to my mind how well
do they keep themselves clear of leaves under a full inflush of water,
they could act like a dam if they don't then water will be lost. most
tanks have screens that will prevent leaves entering the stored water.
be good if they could demonstrate for you
hope you get some answers
'it works for me it could work for you,'
"in the end ya' gotta do what ya' gotta do" but consider others and the environment