Many spray bars use straight bars with a multitude of holes that send moving water into the livewell without direction. Species like sardines, herring and menhaden need directional flow in the livewell to push the oxygenated water across their gills. To this end, sprays with a single jet or curved bar are the most effective.
The downside to directional flow is that too much flow can exhaust baitfish, and most pumps do not allow for adjusting the amount of water flow. Pump volume (in gallons per hour, or gph) and hose diameter determine the rate of water flow out of the spray nozzle. Too much water flow will knock the scales off the delicate baits like shad and threadfin herring and tire them, which is why spray pumps should be rated at less than 500 gph.
If you intend to carry large volumes of bait or want to keep them supercharged, then the venturi systems or bottled oxygen are preferred. Venturi systems are similar to standard spray-jet-pump systems except they have a separate line that introduces air into the water flow just ahead of the pump. The impellers in the pump churn the larger bubbles into smaller bubbles, which are more readily absorbed in the water, thus delivering more oxygen into the flow and the livewell.
No matter how small the bubbles, your aerator is limited in how much oxygen it can introduce. Oxygen content in the atmosphere is roughly 21.5 percent, but you can increase that concentration by adding bottled oxygen as part of an air-stone delivery or venturi system. By adding 100 percent oxygen to your sprayer flow, you increase the oxygen delivered to your bait in the livewell.
With any livewell system, there are tricks to improving the life and heartiness of your baits. A capful of hydrogen peroxide added to the water will supercharge the system, often with enough pop to bring back oxygen-deprived baits.
On hot days or when the livewell will be exposed to direct sunlight, water temperature can be regulated with frozen water bottles in the livewell. Don't remove the cap, as fresh water in the livewell can kill baits.
If you carry baits for more than an hour, change water when you arrive at your destination to remove accumulated waste chemicals, like ammonia, the bait's natural waste products, and carbon dioxide or nitrogen that regularly build up in livewell systems.
As long as you consider oxygen content, water flow, direction and volume, the only limiting factor to keeping your bait alive and frisky should be feeding it and keeping it disease-free.
But those are topics for a long-term bait-storage Game Plan!
About the Author: Capt. Mike Holliday (www.captainmikeholliday.com) is a writer, photographer and fishing guide living in Stuart, Florida, and the author of Sportsman's Best: Inshore Fishing and Secrets for Catching Seatrout.