Compressed oxygen can be stored indefinitely. Various diffusers are used for dispersing oxygen from the bottom of the tank compartment. Carbon stones or rods, MicroporeTM tubing, BioweaveTM, PorexTM, and others work well. Some diffusers are made of PVC frames that fit the bottom of the tank compartment. Agitators are commonly used either alone or in combination with pure oxygen.
Agitators can also provide back-up aeration for emergency situations.
For short trips agitators alone may suffice The combination of agitators with oxygen diffusers works well for fish hauling. Agitators do not have good mixing characteristics alone, and low DO may result in corners of the hauling tank. Oxygen diffusers do not remove carbon dioxide efficiently be-cause of minor agitation at the water surface, but under the high density hauling conditions, they supply oxygen efficiently. Alternators should be heavy-duty, and the vehicle's engine should be kept running during a short stop to keep the battery charged. One agitator per compartment is used.