Yes for the background we had to drain the tank. Fiulling of the tank was just to test if all the systems were running ok and the filtersystem did what we want it to do. No these guys are building the background which has already some spectaculair changes ( hope to hav e foto's soon) . This must dry for one week then another artist will do the painting and sealing of the concrete. Then fil it up again and drain it again and then the original water will go in.
Regards
Frank
Regards
Frank