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 Active Aqua

Active Aqua Water Chiller with Boost, 0.5 HP, 90-172 Gal, Cold Plunge

A half-horsepower chiller rated for 90 to 172 gallons – sized for a full 100-gallon stock tank.

Best for 100 to 150 gallon stock tanksretiring the ice bagsholding one set temperature through the week

The smaller Active Aqua chiller stops at 92 gallons; this one starts at 90 and runs to 172, which puts a full 100-gallon stock tank comfortably inside its range rather than at the edge of it. It is the same hydroponics design – a gunmetal box with a mesh front, a titanium evaporator and a digital panel with a Boost button – rated at 4,020 BTU and 510 W, and its listing now names cold plunges and ice baths as a use.

It is a bare chiller. Water is pushed through it by a separate pump, the box holds fittings but no hoses, and the listing gives no lowest temperature, no cool-down time and no pump range for this model. Nothing on the listing says it may stand in the rain either, so in a yard it belongs under a roof edge or a ventilated shelter, off the ground, with free air around the grille.

Tip: Check the 0.5 HP manual for the pump flow it wants before you buy the pump – the listing does not give it.

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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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