Call or stop by your local Seven Seas Pools & Spas location to walk through the lineup and pick the right shell for your yard.
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Call or stop by your local Seven Seas Pools & Spas location to walk through the lineup and pick the right shell for your yard.
A fiberglass inground pool is a one-piece molded swimming pool shell, manufactured in a factory under controlled conditions, finished with a marine-grade gelcoat surface, and delivered to the install site as a single ready-to-set piece. It is one of three dominant inground pool construction methods in North America, alongside concrete (gunite or shotcrete) and vinyl-liner. Fiberglass is the fastest of the three to install, the lowest-maintenance over the long run, and the only method where the finished surface ships from a factory rather than being built or replaced on-site. Seven Seas Pools & Spas builds fiberglass inground pools from two manufacturers: River Pools out of Fortville, Indiana (a high-volume national manufacturer with ten distinct series, including six rectangular series engineered for auto-cover compatibility), and Nowak Fiberglass Pools out of Amity, Pennsylvania (a small family-owned limited-production manufacturer with ten named models and the only fiberglass pool manufacturer in the state of Pennsylvania).
A fiberglass pool is one piece. The shell is built in a mold at the factory in a sequence of layers: gelcoat (the surface you swim against), vinyl ester resin and chopped-fiber barrier coat (the chemical barrier between gelcoat and structure), fiberglass mat and woven roving in resin (the structural layers), and a final reinforcement layer along the floor and walls. The shell cures in the mold and is then pulled, trimmed, and finished. By the time it leaves the factory it is a complete water-holding vessel: the surface is finished, the steps are molded in, the bench seating is part of the shell, and any tanning ledge or integrated spa is built in as a continuous part of the structure.
That one-piece nature is what separates fiberglass from the alternatives:
Explore River Pools and Nowak fiberglass pool shells with Seven Seas Pools & Spas, compare shapes, finishes, tanning ledges, integrated spas, and cover-ready options, then choose the right one-piece shell for your yard.
Three structural advantages drive the fiberglass-pool market share, which has roughly tripled in the last decade against the broader inground category:
Faster install. A finished shell shows up on a truck. Most of the on-site time is excavation, set, backfill, and decking. A typical fiberglass install runs about two to six weeks from breaking ground to swim-ready, depending on the manufacturer, the size of the shell, and the decking material. The comparable concrete project is three to six months; the comparable vinyl-liner project is four to eight weeks.
Lower lifetime maintenance and chemical load than concrete. The gelcoat surface is inert. It does not absorb pool chemistry, does not promote algae growth in surface pores the way concrete does, and does not need acid-washing or replastering on a 10-to-15-year cycle. You run less chlorine, less acid, and fewer surface cycles over the life of the pool.
No liner replacement. A vinyl liner is a wear part with a 7-to-15-year replacement clock and a four-figure replacement cost each cycle. A gelcoat shell is structural; under proper installation and reasonable chemistry maintenance, it does not need to be replaced.
Two additional structural points matter:
Energy efficiency. Fiberglass is a natural insulator. The shell holds heat better than a concrete pool of the same size, which reduces the heater run-time required to hold a target swim temperature.
Surface comfort. The gelcoat surface is smooth. Bare feet do not get scraped the way they do on a fresh gunite surface or on the seams of a worn vinyl liner.
A typical Seven Seas fiberglass-pool install runs through eight on-site phases:
The shell itself goes in on a single day. The total project timeline is driven by the decking phase and any utility-line work the yard requires, not by the pool itself.
Fiberglass shells are molded in fixed shapes. You pick the model; the shape is what the manufacturer built into the mold. The category covers a broad shape vocabulary across River Pools' ten series and Nowak's ten named models:
| Shape Family | What It Means | River Pools Examples | Nowak Examples |
|---|---|---|---|
| Rectangular | Clean straight-edge geometry, the most architectural look | R Series, A Series, D Series, M Series, T Series, X Series | Atlantis, Grand Atlantis, Zero Entry |
| Freeform | Curves rather than corners, naturalistic landscape look | I Series, C Series | Aruba, Jupiter Island, Subdivision, Play Pool, Avon |
| Roman-end | Rectangular body with a rounded shallow entry, traditional residential pool shape | L Series (L36) | None currently |
| Deep-end specialty | Engineered around a deeper-than-typical deep end | T Series (T40, 8'6" deep end) | Pittsburgh Deep |
| Beach entry | True zero-depth entry slope from deck level down | None currently | Zero Entry |
| Plunge | Compact one-zone pool for tight yards | N Series (N16, N16L) | Little Lounger |
| With integrated spa | Molded-in spa with a spillway into the main pool | X Series, I Series S models | None currently |
| With tanning ledge | Built-in shallow lounging zone for chairs or kids | D Series, I Series, C Series, L Series, M Series, X Series | Jupiter Island TL |
If you want a shape one manufacturer doesn't build, the other often does. River Pools covers Roman-end (L Series) and integrated-spa (X Series, I Series S models) that Nowak doesn't make. Nowak covers true beach entry (Zero Entry) that River Pools doesn't currently mold. For the broadest shape coverage in a single consultation, walk through both manufacturers during your Seven Seas visit.
A fiberglass pool starts with the right shell for your yard, budget, and long-term maintenance plan. Seven Seas Pools & Spas can walk you through River Pools and Nowak options, compare rectangular, freeform, plunge, tanning-ledge, beach-entry, deep-end, and integrated-spa models, then help confirm access, decking, equipment, and installation details before the project moves forward.
Beyond the basic shell shape, fiberglass shells can be molded with a range of feature options. Which features come with which shells is set by the manufacturer and the model; you cannot add a molded feature to a shell that didn't ship with it.
A tanning ledge (also called a sun shelf or baja shelf) is a shallow lounging zone, typically 8 to 12 inches deep, designed to hold a partially-submerged lounge chair or a child playing in shallow water. The ledge is molded into the shell at the factory; the entire River Pools tanning-ledge-capable series share the same standard ledge depths (TL09 at 8 inches or TL15 at 12 inches). Nowak's Jupiter Island TL variant is the only Nowak shell with a factory-built ledge.
Common ledge add-ons that Seven Seas can include in the install:
An integrated spa is a molded-in hot tub attached to the pool shell at the factory, with a spillway edge that pours into the main pool. River Pools offers integrated spas standard on the X Series (X32, X36) and as the S-variant on the I Series (I25S, I30S). Nowak does not currently mold an integrated spa option.
The trade-off vs. a separate standalone hot tub:
If a hot tub is part of the plan, decide between integrated and standalone before you pick the shell. The choice constrains which shells are even on the table.
Some fiberglass shells are built with hidden cover tracks under the coping line for clean integration with a third-party automatic safety cover. River Pools' rectangular series (A, D, M, R, T, X) are all auto-cover ready. The River Pools freeform series (C, I) and the Roman-end L Series are not. Nowak's lineup is not currently engineered with auto-cover-ready coping; a safety net or manual cover is the alternative on a Nowak shell.
If an automatic safety cover is a requirement (for child safety, for local code compliance, or for simplifying winter prep), the choice of shell is constrained to River's rectangular series.
Most fiberglass pools top out around 5'6" to 6'3" in the deep end, which is enough for swimming, casual jumps from the deck, and most underwater play. For a real deep end engineered for deeper-water use, two shells in the Seven Seas lineup go deeper:
Neither shell is enough for a residential diving board under most codes. Diving boards typically require more depth and a specific deep-end profile that one-piece fiberglass shells do not support. For competition diving, fiberglass is not the right construction method; a custom concrete pool is.
A beach-entry pool (also called a zero-entry pool) starts at zero water depth at the entry corner and slopes gradually into swim depth, the same way a beach walks into the ocean. Most beach-entry pools in the broader market are concrete custom builds; fiberglass beach entries are rare because the slope has to be molded into the shell at the factory.
Nowak's Zero Entry is the only beach-entry fiberglass shell in the Seven Seas lineup. The entry corner sits at 4 inches of water and slopes up to a 17-inch wading shelf at 10'6" from the corner, then drops through a stair zone into the main 24'6" swim floor that runs from 3'7" to 6'3" at the deep wall.
Most fiberglass shells include some form of molded-in bench seating, either as a long side bench (the River A Series runs a bench down one full long side) or as built-in curves in the shell (most Nowak freeform models). Bench seating gives you in-water seating without losing center-pool floor space.
Beyond the basic shell shape, fiberglass shells can be molded with a range of feature options. Which features come with which shells is set by the manufacturer and the model; you cannot add a molded feature to a shell that didn't ship with it.
Each manufacturer fields its own palette:
| Manufacturer | Color Options |
|---|---|
| River Pools | Six gelcoat finishes available on every series: Arctic, Caribbean, Diamond, California, Maya, Sandstone |
| Nowak | Three named finishes (Maya Mist, Heavenly Blue Mist, Gray Ocean Mist) plus custom colors on request |
The finish you pick changes how the water reads in sunlight more than it changes the pool's color directly. Lighter finishes (Arctic, Heavenly Blue Mist) read pale and bright; darker finishes (Maya, Diamond, Maya Mist) read deeper and more reflective.
Both manufacturers use marine-grade gelcoats engineered for permanent outdoor exposure. Two notes on surface technology:
Gelcoat is manufactured in batches. The finished shell may vary slightly in tone from the sample chip you saw in the showroom. This is normal for marine-grade gelcoat and is not a defect. The variation is within tonal range; the named color is what you get.
Review shell size, truck access, excavation needs, decking options, gelcoat finishes, water care, and River or Nowak model availability with a Seven Seas advisor.
Fiberglass-pool warranty coverage breaks into two pieces, with notable differences between manufacturers in how they handle the second piece.
Both River Pools and Nowak offer lifetime structural warranties on the fiberglass shell. The structural warranty covers the shell holding water for the life of the pool under proper installation. Failures at this level are rare on a one-piece fiberglass shell, but the structural warranty matters because it underwrites the integrity of the entire investment.
River Pools positions its structural coverage with a written commitment that the manufacturer, not the homeowner, carries the repair burden if the shell fails to hold water (including the cost of draining, refilling, and chemistry rebalancing during a structural repair).
Nowak's structural warranty applies to pools that are properly installed by Nowak directly, by an authorized dealer, or through Nowak's Assisted Installation program.
Most national fiberglass manufacturers offer a separate gelcoat surface warranty. The coverage typically protects against osmotic blistering (the failure mode where moisture migrates through the gelcoat over time and forms small surface blisters).
Nowak's surface warranty is positioned as unusual in the broader industry: Nowak underwrites the surface coverage themselves, while many other fiberglass manufacturers do not offer one because the gelcoat raw-material supplier disclaims warranty coverage on the material. The 2025 granite-chip non-pigmented gelcoat surface change is part of that warranty story: a more chemically and UV-resistant finish supports a more durable warranty position.
Before you sign any fiberglass-pool install contract, Seven Seas walks you through the printed manufacturer warranty document. The four questions worth asking on any fiberglass-pool warranty:
A fiberglass pool needs ongoing sanitization to keep the water safe. Three approaches are common; not all are recommended on every shell.
Traditional chlorine sanitization is the default on every fiberglass shell in the Seven Seas lineup. Sodium hypochlorite (liquid chlorine), calcium hypochlorite (granular), or trichloroisocyanuric acid (chlorine tabs) are all standard options, paired with a chlorine feeder or automatic doser on the equipment pad. Chlorine is well-understood, easy to maintain, and compatible with both gelcoat technologies in the Seven Seas lineup.
A salt-water sanitization system electrolyzes dissolved salt into chlorine on demand. The pool still runs on chlorine chemistry; the salt cell just generates the chlorine in-line rather than requiring manual dosing. Salt systems are popular on the broader pool market for their lower-maintenance day-to-day operation.
Brand positions differ on salt:
If salt-water sanitization is a hard requirement for your project, the brand choice narrows. Talk to Seven Seas during the consultation about the warranty implications of running salt on either shell.
Mineral sanitization (silver or copper ions) is sometimes paired with a reduced-chlorine maintenance routine. Mineral systems are not typically a primary sanitization method; they supplement chlorine. Compatible with both shells.
A fiberglass pool runs lower on lifetime cost than the alternatives in two specific ways:
The day-to-day maintenance on a fiberglass pool is the same as on any other inground pool: skim the surface, vacuum the floor (manual or automatic), brush the walls weekly, test water chemistry weekly, balance pH and alkalinity, sanitize per your system, clean or replace the filter media on schedule. Seven Seas covers the maintenance routine during install orientation and offers ongoing service plans if you want it handled.
Seven Seas builds fiberglass inground pools from two manufacturers. The two brands sit in different parts of the fiberglass market and serve overlapping but distinct shopper profiles.
River Pools is one of the largest one-piece fiberglass-shell manufacturers in North America. Ten series cover the practical range of what fiberglass can do, with broad shape coverage and a specific strength in auto-cover-ready rectangular shells. Six gelcoat finishes are standard on every series. Lifetime structural warranty plus gelcoat surface warranty. Typical install timeline runs 3 to 6 weeks with concrete decking. The full River Pools lineup at Seven Seas covers:
Nowak Fiberglass Pools is a small family-owned manufacturer and the only fiberglass-pool manufacturer in the state of Pennsylvania. Ten named pool models cover the residential range, built in limited production runs with 20% to 30% more raw materials than the high-production industry norm. Upgraded gelcoat finishes come standard on every shell rather than as paid upgrades. Lifetime structural warranty plus a gelcoat and surface warranty (which Nowak underwrites themselves, uncommon in the broader fiberglass-pool industry). Typical install timeline runs about 2 weeks. The full Nowak lineup at Seven Seas covers:
| Axis | River Pools | Nowak |
|---|---|---|
| Manufacturer location | Fortville, Indiana | Amity, Pennsylvania |
| Manufacturing scale | High-volume national | Small-batch family-owned |
| Lineup size | 10 series, ~40 model sizes | 10 named models |
| Auto-cover ready shells | Yes (rectangular series A, D, M, R, T, X) | No |
| Integrated spa shells | Yes (X Series, I Series S models) | No |
| Beach entry shell | No | Yes (Zero Entry) |
| Tanning ledge shells | 6 series include one (D, I, C, L, M, X) | 1 model variant (Jupiter Island TL) |
| Deep-end specialty shell | Yes (T40, 8'6" deep end) | Yes (Pittsburgh Deep) |
| Gelcoat color options | 6 finishes on every series | 3 named finishes plus custom |
| Salt-water sanitization | Compatible | Not recommended per warranty position |
| Structural warranty | Lifetime | Lifetime (proper installation) |
| Gelcoat / surface warranty | Yes | Yes (manufacturer-underwritten, unusual in category) |
| Typical install timeline | 3 to 6 weeks | About 2 weeks |
| Best fit | Broad shape coverage, auto-cover compatibility, integrated spa options | Family-build provenance, upgraded gelcoat standard, limited-production quality control, beach entry |
Neither brand is universally better. The right brand depends on the specific shape, feature, and sanitization requirements of your project. A Seven Seas advisor will walk you through whichever brand fits your project during the consultation.
A fiberglass shell with proper installation and reasonable chemistry maintenance has no defined replacement cycle. The structural shell is a permanent installation. The gelcoat surface holds up for decades; light tonal variation over a long time horizon is normal, but the surface itself does not need to be replaced. This contrasts sharply with concrete (replaster every 10-15 years) and vinyl-liner (replace every 7-15 years).
No. The shells are molded in fixed sizes. You pick the manufacturer, then the series or model, then the gelcoat color and the add-ons (decking, equipment, lighting). If you need a fully custom shape, fiberglass is not the right construction method; concrete is.
The shell is a manufactured product with the surface finished at the factory and a freight cost folded in. A vinyl-liner pool ships components and is assembled on-site. The fiberglass premium up-front is typically offset within 7 to 15 years by avoiding the liner-replacement cycle.
Structural cracks on a one-piece fiberglass shell are rare. The most common surface issue is osmotic blistering on aging gelcoat (the failure mode the gelcoat surface warranty specifically covers). Both River Pools and Nowak warrant the structural shell for the life of the pool under proper installation.
Yes. The shell is structurally stable through freeze-thaw cycles when properly installed and properly winterized. Both River Pools and Nowak ship into cold-winter climates; Nowak is specifically engineered out of Southwestern Pennsylvania, where winter temperatures regularly drop below freezing.
Yes. The inert gelcoat surface handles UV exposure and high water temperatures without surface degradation. The lighter gelcoat finishes hold color longest in high-UV regions.
Some manufacturers (Nowak's Assisted Installation program in particular) ship the shell and equipment to a homeowner or contractor for self-install. River Pools does not offer a self-install program; their pools install through authorized dealers like Seven Seas. The work involved is non-trivial (a 16,000-pound shell, a crane, plumbing, electrical) and most buyers go through a builder.
"Composite" is a marketing term that some manufacturers use for fiberglass shells. The structural difference, if any, is in the specific lay-up (fiberglass mat plus woven roving plus reinforcement layers) rather than in the use of a different material. In practice, the categories overlap heavily.
On a River Pools shell, yes; the warranty does not exclude salt. On a Nowak shell, the warranty position is that salt is not recommended; talk to Seven Seas about the implications before converting an installed Nowak from chlorine to salt.
Lead time depends on the manufacturer's production queue. Nowak's typical timeline from order to install is shorter (limited production, single facility). River Pools' typical timeline is longer in peak season due to higher demand against a national production schedule. Seven Seas confirms the current lead time for both manufacturers during the consultation.
Walking both manufacturers in person during a single visit is the fastest way to pick the right fiberglass shell. Call or stop by your local Seven Seas Pools & Spas location to walk through the River Pools series, the Nowak models, the gelcoat sample chips, and the dig diagrams for the specific shells that fit your yard.
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