I obviously did it all wrong then :roll: :lol:
We had a 3ft tank. We took several barrels down the coast and filled them with water, rocks and any critter we could catch. This included shrimps, anemones, rockfish, triplefins, brittlestars, chitons, sea cucumber, various starfish, and a hermit crab.
We had an AquaClear filter hanging off one end.
The tank was topped up occasionally with fresh water and once every few months we went to Rarangi Beach and got fresh sea water. We also added sea lettuce. This always had lots of microscopic critters stuck in it for food for the inhabitants.
That's it. All were happy. We had no deaths except for a baby octopus that escaped.