Master Spas hot tub sizes and water capacity
Master Spas's 4 listed models hold from 305 to 2325 gallons. Find yours below for its water volume, dimensions, and seating, then size your chemicals to that figure.
| Model | Type | Gallons | Dimensions (in) | Seats |
|---|---|---|---|---|
| Twilight TS 7.25 | Hard-shell | 305 | 84 x 84 x 38 | 7 |
| Twilight TS 8.25 | Hard-shell | 395 | 94 x 94 x 38 | 7 |
| Michael Phelps MP Force Deep | Swim spa | 1935 | 215 x 94 x 60 | – |
| Michael Phelps MP Momentum Deep | Swim spa | 2325 | 231 x 94 x 60 | – |
Why your gallons matter
Every chemical dose is sized from your water volume, so the gallons figure is the one number to get right before you balance the water. Open any model above for the exact doses for its volume, or take the number to the dosing calculator. Capacities are the maker's stated figures; confirm against your own manual when precision matters.