Simply Koi and More Koi

Hi all,
Had my pond up and running now for 3 weeks and wondering if any of you had a clever idea of fitting a auto top up for water level,
i am running 2 Nexus 300, any ideas would be helpful.


Thanks Paul.

some use these fitted somewhere on one of the filters
[img]http://www.screwfix.com/sfd/i/cat/78/p4748578_l.jpg[/img]