Drained/Dumped Tanks 1,2 & 5 total 7,600l to remove fowled water. Rinsed and cleaned Tanks 1,2 & 5.
To accomplish this turned off exit valves in Tanks 3-4 and open dump valve to outside to let Tanks 1, 2 & 5 to gravity drain... then Closed valves on Tanks 1,2 & 5 and reopened valves on Tanks 2-3.
Restarted filtration system.
Backwashed filter, topped up sump and added 100 gms of Bi-Carb Soda.
Hosed out ARC using bleach and disinfectant.
Topped up Tank 7 (Yabbies) and Aquarium 1 and 3.
Left roller door partly open to encourage flow of fresh air.