Science: Livewells and Peroxide

It’s a controversial topic on the message board forums, but when the lakes get as hot as they are now, I keep a bottle of hydrogen peroxide handy to help keep my catch alive during the summer heat.

That said, there are a few guidelines I use, and some interesting facts I’ll pass along that you won’t read in most pieces written on the subject.

• Different species have different tolerances to hydrogen peroxide. Some, like walleye, are extremely sensitive to even small amounts. Don’t use it except for keeping bass alive in a tourney situation. Fortunately largemouth have a better tolerance for it than many other freshwater fish, including other members of the sunfish family such as bluegills.
• Different life stages of a particular fish changes it’s ability to handle doses of hydrogen peroxide. Eggs can withstand the highest concentrations, while young adults have the lowest tolerances. Data suggests that there is a slight uptick at the end of the downward curve, with older adults usually able to tolerate slightly higher concentrations than younger adults.
• Water temperature matters. The warmer the water, the less hydrogen peroxide a fish is able to tolerate.
• It’s a balance between dose/concentration and time. Bass can tolerate a higher amount for very short periods of time, but require a considerably smaller concentration if they are going to be exposed to the chemical for a longer length of time (24-96 hrs.).
• Warmer water can not hold as much oxygen as colder water. Saturation point at around 90 degrees is slightly less than 7.5 ppm oxygen. This is at sea level. At higher altitudes your rate will be lower. The amount of peroxide I add has been shown to raise oxygen saturation by between 1.0-1.5 ppm for the typical livewell volume.
• At a certain point, overdosing leads to guaranteed mortality. More is not better! Unless you want to risk a livewell full of dead bass, don’t add more than what is generally recommended. I actual error on the side of caution because of the notes above and typically underdose to be safe.

Most sites, videos and advice have you calculate some form of measurement for your livewell based upon a calculation of your livewell size. Problem is, many livewells are weirdly shaped, and some people just don’t want to try and calculate exactly how big their well is. Plus, what you need is the volume as relates to how much water you will actually have in the well, and that will depend upon how high you can fill your well before things like overflow valves start draining the excess out. This can be difficult to calculate.

Fortunately, most newer boat models typically have the volume stated online at the manufacturers website. Many older model boats you won’t have a clue. Still, the large majority of bassboat livewells regardless of model fall between 12 and 25 gallons.

Turns out that the little Solo bathroom cups we have around the household are 3 ounces. That makes life simple because in nearly every scenario, just 1 or 2 of these little cups full of peroxide is all you need based on if your livewell falls to the higher or lower end of the spectrum. Simply add and then forget about it. Never add any more unless you end up draining and refilling your well at some point througout the day, and then just add back in one or two of those little cups and you’ll be good to go. Remember, less is really more in this case.