I use a 120 qt Coleman in an open 16 ft G3 without a consul. Lakes where I fish are limited to essentially 20 hp. Inside the cooler water is introduced by a pump placed in the lake. In the summer I will add enough hose to sink the pump 6 to 8ft with a decoy weight to pump cooler water. In the cooler a brass garden hose splitter is attached to the side of the cooler. The pump is the attached to the input side. One output is angled at the surface for circulation of the water. The other is routed to a filter basket attached at the along the side as close to the top as possible. I purchase bulk activated carbon filter medium used in large commercial bait tanks. The carbon is placed in a zipped mesh bag that comes with the charcoal. I regulate the flow of water with the ball valves in the brass garden hose fixture. (Anyone who has had to keep shad alive knows the importance of removing the ammonia created by the fish waste). I use a 12 volt aerator with an airstone to help introduce oxygen. Essentially it's an aquarium. I will fill the cooler first thing in the morning. Filling it a little better than half way gives me better than 16 gallons. I start the day with 3-2 liter bottles frozen. With 80 plus degree water this will usually drop the temp to around 70. I add a granular treatment and will also use a liquid calming chemical (Tranquil) used for transport of fish and minnows especially at weigh-in to reduce stress and lower metabolism. There is an aquarium thermometer in the water so I can monitor temps. If needed (rarely) I will add ice from my drink cooler. I use ice from my deep well so chlorine is a non issue. It's a lot but it works.
