The Square Spa by Thursday Pools is a seven-person inground fiberglass spa that delivers the bubbling water, muscle relief, and stress reduction that most homeowners think requires a separate above-ground unit or a resort visit. It comes in two configurations, one with a spillover water feature and one without, and its clean right-angle shape integrates naturally with most pool designs and rectangular patio layouts. Thursday Pools describes it as the kind of place where you “sit back, relax and enjoy alone or with six of your best friends,” and that captures exactly what the Square Spa is: a permanent, low-maintenance, full-capacity hydrotherapy space that belongs in the yard for the long haul.
Square Spa Thursday
Pool
Get to a Healthier You
What Is the Square Spa?
The Square Spa is a compact square fiberglass inground spa available in two configurations:
Square Spa without Spillover: O.D. 9′ x 9′ 3’2″ | I.D. 8’1″ x 8’1″ 2’11.5″ | 900 gallons
Square Spa with Spillover: O.D. 9′ x 9′ 3′ | I.D. 8’1″ x 8’1″ 2’11.5″ | 900 gallons
Both hold 900 gallons and seat up to seven people. The Square Spa with Spillover includes a water flow feature that can be directed from the spa into an adjacent pool or over a deck edge, adding visual movement and ambient water sound to the overall pool area. The Square Spa without Spillover is the cleanly integrated option for homeowners who prefer an uninterrupted spa perimeter or whose pool layout does not require or benefit from a spillover.
Both versions feature Thursday Pools’ standard non-skid gel coat finish throughout and are auto-cover ready.
What the Square Spa Is Not
The Square Spa is not a swimming pool or wading pool. Its 9′ x 9′ footprint and 3′ depth are designed for seated hydrotherapy, socializing in heated water, and relaxation, not for lap swimming, active play, or standing exercise. If your household wants a water feature that doubles as an exercise space or that accommodates children playing, the Wading Pool or one of Thursday Pools’ primary pool designs is the more appropriate direction.
The Square Spa is also not the Grand Spa. At 9′ x 9′, it is the mid-size option in Thursday Pools’ spa lineup, sitting between the 8’6″ x 8’6″ Round Spa and the 11’6″ x 11’10” Grand Spa. For households that want maximum interior volume, more bench space, or a spa that reads as a centerpiece rather than a complement, the Grand Spa provides that. The Square Spa is the right choice for buyers who want proven seven-person hydrotherapy capacity in a compact, angular form that disappears cleanly into most pool deck designs.
Why Thursday Pools?
Thursday Pools is the only fiberglass spa and pool manufacturer in the United States to hold ISO 9001 certification for quality management, and their manufacturing practices also meet ISO 14001 standards for environmental stewardship. These are not marketing claims. Both are independently audited certifications that govern how Thursday Pools designs, produces, and tests every product at their Fortville, Indiana facility, including the Square Spa.
The gel coat finish on the Square Spa is the same non-skid, algae-resistant surface standard across all Thursday Pools designs. In a heated spa where warm water accelerates algae growth, a gel coat surface that is genuinely impervious to algae is not a minor detail. Thursday Pools builds this into the shell, reducing the chemical demand and cleaning effort associated with spa ownership. The non-skid surface throughout the floor and bench area also provides safe footing in a warm, wet environment where traction matters.
The Square Spa’s auto-cover readiness is equally relevant in Ohio. A heated inground spa that is not covered between uses loses temperature, accumulates debris, and drifts from chemical balance faster than a covered one. Thursday Pools designs the Square Spa to accept an automatic cover system as a planned-for feature rather than an afterthought.
Why Fiberglass, and Why the Square Spa?
Portable above-ground spas are built with acrylic shells that fade under UV exposure, degrade at the seams, and require ongoing shell maintenance that an inground fiberglass spa does not. The Square Spa is a permanent structure molded from the same fiberglass material as Thursday Pools’ full-size pool designs, and the gel coat finish resists staining, algae, and surface deterioration across years of use without requiring resurfacing.
At 900 gallons, the Square Spa heats efficiently and holds temperature well, particularly when covered between uses. For Ohio families who want to extend their outdoor season through fall or enjoy their spa through cold-weather months, a compact, well-insulated fiberglass structure heats faster and costs less to maintain than a larger water volume would. The Square Spa’s right-angle geometry also integrates cleanly with rectangular pool designs and straight-edged patio layouts, which is why it appears in Thursday Pools’ own gallery images alongside several of their primary rectangle pool models.
Ready to Enjoy Alone or With Six of Your Best Friends?
Relaxation that lasts requires a structure built to last. The Square Spa by Thursday Pools is a permanent, low-maintenance, full-capacity hydrotherapy feature that becomes part of your outdoor space in a way a portable unit never will. At Ohio Paradise Pools, we have been installing pools and companion features for Northeast Ohio families for over 32 years. We are family-owned and full-service, and we include our two-visit pool school with every installation so you know your system thoroughly before we consider the project complete.
Call us today at (440) 610-5484 or schedule a free consultation to begin planning your Square Spa installation in Edison Park and the surrounding Ohio communities.
Available Sizes
Sit back, relax and enjoy alone or with six of your best friends.
Sit back, relax and enjoy alone or with six of your best friends.
Square Spa FAQs
What is the difference between the Square Spa with Spillover and without Spillover?
Both configurations hold 900 gallons, fit seven people, and share the same 9′ x 9′ outside footprint and 8’1″ x 8’1″ interior dimensions. The difference is that the spillover version includes a water flow feature that directs water from the spa into an adjacent pool or over a nearby deck edge, creating the visual and auditory effect of moving water between the two structures. The spillover configuration has a slightly shallower depth (3′) compared to the non-spillover version (3’2″), which accounts for the spillover mechanism. The choice between the two is primarily about whether the spillover water feature fits your pool design and aesthetic preference. Ohio Paradise Pools will show you both options in the context of your specific layout during the consultation.
How does the Square Spa's shape complement most pool designs?
The Square Spa’s right-angle corners and straight sides align naturally with rectangular pool designs and straight-edged patio geometry. Thursday Pools’ own photography frequently shows the Square Spa positioned adjacent to rectangle models like the Monolith, where the angular spa and angular pool create a cohesive visual set. For homeowners with a geometric backyard layout, a clean patio grid, or a preference for modern angular aesthetics, the Square Spa reads as an intentional part of the design rather than an add-on. The Round Spa’s circular shape is a different aesthetic choice that works well with freeform designs and curved landscaping. Ohio Paradise Pools can walk you through both options in relation to your primary pool design before you decide.
How many people does the Square Spa seat, and how is it configured?
Thursday Pools specifies that the Square Spa seats seven people. The bench seating runs around the interior perimeter of the spa, creating a facing arrangement where everyone in the spa can converse and make eye contact. For the ideal client who entertains, this capacity means the spa can hold a full group of adults while the children play in the primary pool, keeping everyone in visual contact and connected across the pool area. For couples or smaller families, a seven-person spa provides generous personal space for each user and flexibility for those occasions when the group is larger.
What health benefits does the Square Spa provide, and when are they felt most?
Thursday Pools notes that a spa can help promote better sleep, relieve muscle tension and pain, and reduce stress, and these align with the documented effects of warm-water hydrotherapy. Heat and pressure from the jets increase blood circulation, relax contracted muscle tissue, and help reduce chronic tension in the back, neck, and joints. For Ohio families using their spa after active summer days in the pool, or for adults who want a recovery routine after exercise, the effects are felt most consistently with regular use at therapeutic water temperatures. The Square Spa’s compact 900-gallon volume heats to temperature faster than a larger spa, which means shorter wait times and lower heating costs per session.
Can the Square Spa be installed as a standalone structure without a primary pool?
Yes. The Square Spa is an independent fiberglass structure with its own shell, plumbing, and heating system. It does not require a primary pool to function. Thursday Pools designs it as a complement to their pool lineup, but Ohio Paradise Pools installs it as a standalone wellness feature when that is what the project calls for. For households that want a permanent inground hydrotherapy feature in a space where a full pool is not practical or desired, the Square Spa at 9′ x 9′ is a manageable footprint and a full wellness investment.
Is the Square Spa auto-cover compatible, and what does that mean for Ohio owners?
Yes. Thursday Pools designed the Square Spa to accept an automatic safety cover. For Ohio pool and spa owners, covering the spa when not in use is particularly important given the extended offseason from roughly September through May. A spa left uncovered through Ohio’s fall and winter accumulates debris, loses heat, and requires more chemical intervention each time it is used. An auto cover eliminates that maintenance burden, keeps the spa inaccessible to unsupervised access, and makes the spa dramatically easier to manage over the full calendar year. The Square Spa’s right-angle geometry also means auto-cover hardware integrates cleanly with the shell, without the fitting complexity of a curved or freeform design.
How does the Square Spa compare to the Grand Spa?
The Square Spa and Grand Spa are both Thursday Pools inground fiberglass spas, but they serve different scales of use. The Square Spa is 9′ x 9′ with 900 gallons and seven-person seating. The Grand Spa is 11’6″ x 11’10”, significantly larger in footprint, and represents Thursday Pools’ premium, resort-scale spa experience. If you want maximum interior space, a spa that can be the visual centerpiece of the pool area rather than a complement, or the most immersive soaking experience Thursday Pools offers, the Grand Spa is the right direction. If you want a full-capacity seven-person spa in a compact footprint that integrates cleanly with a primary pool, the Square Spa delivers that efficiently.
How long does installation take?
The Square Spa is a one-piece fiberglass shell. When installed as part of a primary pool project, it typically adds minimal time to the overall project timeline since the plumbing and electrical work are coordinated as a single scope. When installed as a standalone structure, most Square Spa installations are complete within approximately 1 to 2 weeks depending on site conditions, permitting, and any surrounding deck or patio work. Ohio Paradise Pools manages the entire process and provides regular project updates throughout the build, including FaceTime check-ins when you cannot be on-site.
What warranty does the Square Spa carry?
Thursday Pools backs the Square Spa with a lifetime structural warranty on the fiberglass shell and a 15-year surface warranty on the gel coat finish. The structural warranty covers the shell against material and workmanship defects. The surface warranty covers the gel coat against delamination and structural failure. Ohio Paradise Pools adds over 32 years of local installation experience, an A+ BBB rating, and three consecutive Cleveland swimming pool contractor of the year awards (2022, 2023, 2024) to that manufacturer coverage. When a question about your spa comes up five or ten years from now, you have both a manufacturer warranty and a local team that knows your installation.
How does the Square Spa's maintenance compare to a portable above-ground hot tub?
The Square Spa’s fiberglass shell with Thursday Pools’ gel coat finish resists algae without the chemical scrubbing that acrylic spa surfaces often require as they age. The fiberglass does not fade under UV exposure the way an above-ground spa cabinet or acrylic shell does, and there are no seals, gaskets, or covers to replace on a vinyl liner schedule. Routine care involves regular chemistry testing, filter maintenance, and occasional draining and refilling on a schedule appropriate to the usage load and water chemistry. Ohio Paradise Pools walks you through this routine during our two-visit pool school, covering Ohio-specific water quality considerations so you manage your spa confidently from the start.