North Sanctum
A black oval stock tank cold plunge with a half-folded black lid in a small fenced yard, a gray chiller on a shelf under the shed eave, a floating thermometer and a black step stool with a towel
Cold Plunge Polar Protector

Polar Protector 100 Gallon Oval Stock Tank HARD Insulated Cover

A rigid foam lid cut for the oval 100-gallon stock tank, with buckles that hold it on in wind.

Best for 100-gallon oval stock tanksoutdoor tubs under treesholding the chiller's work between plunges

A stock tank with no lid gives back the cold a chiller worked for and collects every leaf in the yard. This Polar Protector is a rigid lid made for the 100-gallon oval tank: an EPS foam core in a black fabric shell, 32 × 52.5 in (81 × 133 cm), held on by six hooks with tightening buckles and finished with a skirt that closes the gap at the rim. In the photos it folds in half down the middle, which makes it a one-person job to take off and put back.

The listing gives no thickness and no insulation value, so how much difference it makes is not a number anyone can promise; covered water simply loses its cold more slowly than open water. It is not a safety cover and does not claim to be. Measure the rim before you order – the maker asks for that in capital letters.

Tip: Run the chiller hoses over the rim at one end, under the fold, so the gap they leave is in one place and the buckles still close.

Photos & price on AmazonAffiliate link

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A black oval stock tank cold plunge with a half-folded black lid in a small fenced yard, a gray chiller on a shelf under the shed eave, a floating thermometer and a black step stool with a towel
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