Other FAQ sections: Service FAQ · System Technical Support

6 questions

What are your main product lines?

Three industries, organised by system rather than by isolated SKU.

Spa components — whirlpool system (spa pumps, water jets, heaters, suctions, air controls, hoses & fittings), bubble system (air jets, blowers, air manifolds, air hose), sterilisation system (ozone generators, UV lamps, venturi), water feature system (fountains, waterfalls), audio-visual system, support system (spa covers, cover lifters, steps, handrails, caddies), electric control system, circulatory system, thermostatic system, framework system, LED light system.

Bathtub components — whirlpool system, bubble system, water inlet system (faucet sets, waterfall faucets), comfort system (pillows, armrests), support system (brackets, bathtub feet), electric control, LED lighting, ozone, aromatherapy, drainage and thermostatic systems.

Shower room accessories — hand showers, rain shower heads, mixing valves, shower risers, holders and connectors, shower hoses, drains, glass support bars, tempered glass, pulleys, handles, hinges, magnet strips, seats, armrests, back massage jets, foot massage units, top lights, shower room controllers.

Expanded categories — our product development now reaches beyond bathroom components into complete units and accessories for wellness and leisure environments, currently including sauna rooms, sauna accessories, ice baths and cold plunge tubs, with the range still growing.

We also publish pre-matched Hot Tub System Sets (whirlpool / bubble / LED / control) for buyers who prefer a ready-configured system, plus quarterly New Products releases.

How do I choose between 304 and 316 stainless steel?

Both are stainless steel; the difference is corrosion resistance. 304 is adequate for standard freshwater domestic use. 316 contains molybdenum and resists chloride and salt corrosion far better, which matters for:

• commercial and high-bromine/chlorine water treatment
• coastal or saltwater installations
• markets with hard water or aggressive sanitiser regimes

For buyers in cold-climate and high-usage markets, we normally recommend 316 faces on jets and suctions.

Full comparison: 304 or 316 Stainless Steel Jets. Our own upgrade of air jet bodies from PVC to 304/316 is described in the Product Upgrades section below.

What is the difference between air jets and water jets, and which do I need?

Water jets are driven by a pump and deliver directional hydrotherapy pressure. Air jets are driven by a blower and produce a lighter, full-surface bubble effect. Most premium tubs use both, on separate circuits.

Detail: Air Jets vs. Water Jets in Spa Systems and Ultimate Guide to Different Types of Spa Jets and Their Applications.

Do you supply complete systems or only individual parts?

Both. Individual replacement parts are available for service and spare-part business, and we also supply pre-matched Hot Tub System Sets — whirlpool, bubble, LED and control systems delivered as verified assemblies.

For LED in particular we recommend the full-kit approach, because mixed-source lights and transformers are a frequent failure point: Hot Tub LED Lights Failure? Ensure Compatibility by Ordering Full Kits from One Supplier.

Broader context: Hot Tub OEM Assembly: System Architecture, Dependency Chains, and Production Logic.

Do you supply spare and wear parts for models you did not originally manufacture?

Yes. Cross-brand replacement is a core part of our business — filter cartridges, jet internals, seals, pillows, hoses, air controls and cover parts. Send a photo and the original dimensions, and our team will identify a compatible equivalent.

See Sourcing Compatible Spa Parts from China: What to Know and How to Identify and Replace Worn Spa Jets.

Are your products suitable for cold-climate markets?

Yes, and this is a specification decision, not a marketing claim. For markets with sustained sub-zero winters we advise:

• 316 stainless faces on jets and suctions
• cover materials rated for snow load, not only for insulation
• freeze-protection logic on the controller
• UV-resistant, weather-grade plastics (see the Material Customization section)
• winter operation and drain-down guidance supplied to the end user

See From Frost to Snow Load: Selecting Hot Tub Cover Materials for Winter-Ready Markets and Hot Tub Winter Care.

3 questions

What is the difference between OEM and ODM?

OEM — visual branding. The product itself is unchanged; your brand identity is applied through logo marking, colour application and packaging design. This is the fastest and most cost-effective route to a branded line.

ODM — core development. This covers material configuration, precise structural design, functional innovation and process optimisation, and directly determines the market competitiveness and brand value of the product. It includes:

• Material and surface finishing configuration
• New product development — appearance, function, dimensions, mould opening and sampling
• Upgrades to existing products — engineering optimisation plus user and client feedback
• System solutions — from function to system, and from system to matched components

Overview: Hydrorelax Spa & Bathtub & Shower Parts Customization Solutions and the Your Preferred Partner page.

Which categories does your customization service cover?

Bathtub components, spa components, shower room accessories and their related products. All five customization types — logo, colour, packaging, material and surface finishing — are available across the three categories.

Feasibility for an individual product depends on its material and structure; confirm with your sales contact.

At what stage should material and surface finishing be decided?

At the preliminary stage of product development. Material and surface finishing customization is the front end of ODM development, and it determines the structural design, tooling plan and system integration path that follow — get this wrong and every later step has to be reworked.

10 questions

Which logo marking techniques do you support?

Seven single techniques plus one combined technique, matched to different material surfaces.

Technique	Typical application
Screen printing	Spa covers, spa steps, bathtub and spa control panels, controller plastic housings
Inkjet coding	Spa and bathtub hoses, PVC pipes and other pipe fittings
Nameplate sticker	Pumps, blowers, ozone generators, controllers
Sewn fabric label	Spa covers
Embroidery	Spa covers
UV printing	Bathtub, spa and shower room accessories
Laser engraving	Stainless steel and metal faces; bathtub, spa and shower accessories
Screen printing + heat pressing	Spa covers, especially outdoor or high-frequency use

Logo customization requires the item to reach its MOQ.

Can several techniques be combined on one product?

Yes. As long as the product material allows it, you can combine techniques as required. The most common combination is screen printing followed by heat pressing, described below.

How does screen printing work, and what are its characteristics?

Ink is transferred onto the product surface through a mesh stencil, then air-dried or UV-cured to form a lasting image.

Characteristics: durable, abrasion-resistant and waterproof, with good colour retention, suitable for outdoor and humid environments; economical and well suited to large production runs; supports custom patterns and QR codes.

Applied to: spa covers, spa steps, bathtub and spa control panels, controller plastic housings.

How does inkjet coding work, and what suits it?

Fine ink droplets are sprayed onto the product surface through a nozzle to form text or patterns. Printing is clear and throughput is high, and it flexibly prints specification parameters and batch numbers, which suits large-scale line production.

Applied to: spa and bathtub hoses, PVC pipes and other pipe fittings.

How are nameplate stickers made, and what are their characteristics?

Brand artwork is transferred precisely onto a plastic or metal substrate by screen printing, digital printing, thermal transfer or etching, then covered with a protective layer to form a durable self-adhesive nameplate.

Characteristics: wide choice of textures and colours, abrasion- and fade-resistant, strong brand recognition and a premium appearance.

Applied to: pumps, blowers, ozone generators and controllers, for displaying logos and product information.

How is a sewn fabric label applied?

A classic woven or printed fabric label is stitched onto the product surface. The look is understated and durable, with a standard label size of 5 × 1.5 cm, suited to customers who prefer a restrained brand presentation.

Applied to: spa covers, stitched onto the cover surface.

What does an embroidered logo look like?

The logo is embroidered directly onto the product surface with needle and thread, producing a raised texture. The effect is dimensional and tactile with a high-end appearance, suited to customers with higher brand image requirements.

Applied to: brand logo customization on spa cover surfaces.

What is the difference between UV printing and laser engraving?

UV printing cures ink rapidly with ultraviolet light; laser engraving uses a laser beam to etch a permanent logo directly into the product surface.

What they share is coverage: both work across a wider range of product types and materials, and can render a brand mark on almost any visible surface. Applied across bathtub, spa and shower room accessories.

What is screen printing combined with heat pressing?

The logo is first screen printed onto the product surface, then heat pressed — heat and pressure bond the image more tightly to the surface.

It combines the clarity of screen printing with the durability of heat pressing, giving stronger adhesion and better resistance to peeling. Applied to spa covers, particularly for outdoor or high-frequency use.

What logo options are available for spa covers?

Spa covers offer five logo customization methods:

• Sewn fabric label
• Printing, including QR codes and custom patterns
• Embroidery
• Screen printing
• Screen printing + heat pressing

For outdoor or high-frequency use we recommend the fifth option.

5 questions

Can product colours be customised?

Yes. Our products normally come with a standard colour swatch for quick selection, with no additional development cost.

Can I choose a colour outside the standard swatch? Is there a minimum order?

Colours outside the standard swatch can be customised, but colour customization on components carries a minimum order quantity (MOQ). MOQ is set per product — contact us to confirm for your item.

Does colour customization affect the material or the production process?

No. Colour customization applies to appearance only and does not change the material, production process or surface treatment. It can be implemented quickly while keeping your brand visual identity consistent.

Is colour customization suitable for large production runs?

Very much so. The standard swatch route requires no extra development cost, which makes it particularly suitable for large runs and entry-level OEM customization.

Which parts can be colour-customised, and what colours are available?

Product	Customisable part	Colours available
Pipes	Pipe body	Multiple colours; see the standard swatch, physical samples available
Spa cover	Outer skin (surface material)	12 standard swatch options including navy, maroon and black, with physical colour samples
Pumps and blowers	Housing (pump body)	Blue, yellow, green, silver-grey and others
LED lamp drivers	Housing	Black, blue, white
LED lights	Housing	White, stainless steel, gold, black, chrome and others
Jets	Jet face	White, chrome, matte black, gunmetal grey, brushed gold
Drain fittings	Face cover	Multiple colour and texture combinations; see the Surface Finishing section

The colour-changing modes of LED lights can also be customised — contact us to confirm the options.

9 questions

What types of packaging customization do you offer?

Two categories, selected according to the order: bulk packaging and retail packaging.

What packaging materials are available for individual products?

Depending on the product and the protection required: plastic bags, bubble wrap, paper, or dedicated plastic protective covers — the last of these is particularly suitable for products with metal surfaces, to prevent scratching in transit.

How is packing safety ensured when several products ship together?

Main components are packed together in durable bags; small parts are bagged separately to prevent them rubbing against each other or getting lost.

How are products protected inside the carton?

Bubble wrap or foam is selected as filling material according to the gaps and shapes inside the carton, creating a stable protective environment for the products.

Can the outer carton be customised? Is it worth doing?

Yes, we offer outer carton customization — company logo, product information and handling marks can be printed on the carton surface.

Whether to do it is your decision. Carton customization generally improves professionalism and brand exposure while ensuring transport safety and easy identification in the warehouse — the value is clearest for buyers with a distribution network.

What retail packaging formats do you offer?

Three formats, all suitable for supermarket and online sales channels: custom hanging card packaging, custom brand colour boxes, and custom set/combo packaging.

What is custom hanging card packaging suited to?

Single-item display in supermarket and online channels. It balances product protection with visual appeal, helping improve the purchase experience and brand recognition.

What products suit a custom brand colour box?

Accessories such as spa filters, for shelf display in supermarket and online channels. Brand artwork and product information can be printed on the box, strengthening shelf presence and brand recognition.

What products suit custom set packaging?

Products where several matching items are combined into one set for retail — a shower kit, for example. It lets the end consumer buy a complete set in one purchase, and raises both brand image and product value.

9 questions

What is material customization, and why does it matter?

Material and surface finishing customization is the preliminary stage of ODM product development, laying the foundation for the product design and system integration that follow.

Material directly affects durability, feel and perceived quality. Customising it lets you select the most appropriate material for each application and market, balancing cost against quality while building a genuinely differentiated product.

How wide is your material selection?

Ten plastics: ABS, PVC, PP, PS, PE, PA, PC, PU, EVA, TPE

Four metals: stainless steel, zinc alloy, aluminium alloy, brass

Four common surface treatments: electroplating, brushing, polishing, spray painting — further options are listed in the Surface Finishing section.

All of these can be freely selected and upgraded during the customization stage. For materials outside this list, contact us to confirm feasibility.

How much does material affect the service life of hardware?

Considerably. Material directly determines corrosion resistance, load capacity and wear resistance, which in turn set the overall service life. Choose according to the actual operating environment and product positioning — not on unit price alone.

What are the characteristics of the four metals?

Material	Characteristics	Common components
Stainless steel	Corrosion-resistant and high strength; the upgrade direction for premium spa and bathtub components	Jet faces, handrails, rollers, bathtub hoses
Zinc alloy	Excellent formability and plasticity, compatible with many surface treatments	Hinges, handles — with electroplating for both appearance and durability
Aluminium alloy	Lightweight and corrosion-resistant, balancing strength against weight	Support bars and rails in sliding systems
Brass	Corrosion-resistant, resilient and easy to machine; suits traditional or retro styling	Handle components

For the choice between 304 and 316 stainless steel, see the Product Range & Selection section above.

Do your plastics meet export market environmental standards?

Yes. All product materials comply with the European REACH and RoHS standards. For the European market we use a non-toxic, lead-free and recyclable raw material system, ensuring both product safety and environmental compliance.

How much does heat resistance vary between plastics?

Considerably. Material must be selected against the actual temperature of the environment the component sits in.

Material	Approximate upper temperature limit
PVC	60 °C
ABS / PU	80 °C
PS	90 °C
PP	100 °C
PC	110 °C

Hot water lines and areas around the heater cannot use the standard PVC specification.

Where is each of the ten plastics used?

Material	Characteristics	Common components
ABS	Tough, lightweight, easy to machine, platable and paintable, good impact resistance; yellows and ages under prolonged UV exposure	Jet faces, drain covers, spa steps, filter housings and other non-pressure parts
PVC	Strong chemical resistance, good sealing, low cost, easy to machine; upper limit around 60 °C, unsuitable for high impact or high pressure	Spa water pipes, air pipes, drainage systems, air hose connectors
PP	Better heat resistance and toughness, lower density, non-absorbent, excellent chemical stability, resists ageing and cracking over time	Bathtub foot pads, spa steps, spa caddies
PC	High transparency, impact-resistant, heat-resistant and flame-retardant; surface scratches easily and needs a protective coating, higher cost	LED lens covers, transparent inspection windows, control panels
PS	High moulding precision, good surface gloss, low cost; brittle with poor impact resistance and limited heat resistance, unsuitable for load-bearing parts	Spa skirt PS panels and other non-structural decorative parts
PU	Soft and elastic, pressure- and wear-resistant, skin-friendly, mouldable into complex shapes; weaker heat resistance, may soften under prolonged hot water immersion	Headrests, massage backrests, armrest edging and other parts in direct body contact
PE	Good waterproofing, flexible, low-temperature and UV resistant, low cost	Low-pressure hoses, shower room waterproofing components
PA	Resilient, dimensionally stable, high strength, wear- and impact-resistant	Spa cover lifters
EVA	Soft, lightweight, waterproof, excellent cushioning	Spa and bathtub pillows
TPE	Excellent elasticity and softness, tolerant of high and low temperatures, recyclable	Bathtub hoses, sealing gaskets

How do plastic requirements differ between outdoor and indoor spas?

Outdoor requires UV resistance, weatherability and ageing resistance — we recommend PC and weather-grade ABS.

Indoor is more flexible on decorative quality and cost, and standard ABS is sufficient.

This matters most in markets where outdoor spas dominate, such as Poland, the Baltics and Romania. Using indoor-grade ABS on an outdoor unit will yellow and embrittle within two or three winters.

How does plastic selection differ between commercial and residential spas?

Commercial units run at high frequency and demand greater durability and pressure resistance — we recommend PC and high-strength ABS.

Residential units run less frequently, so conventional materials such as ABS and PVC are sufficient and keep cost under control.

14 questions

Which metal surface finishing processes do you offer?

Four common processes: electroplating, brushing, polishing and spray painting, customisable to requirement and balancing functional protection against decorative effect.

Further options beyond these four are available — contact us to discuss.

Does the finishing result differ between materials?

Noticeably:

• Stainless steel — brushing, polishing, matte black and similar finishes
• Zinc alloy — suits electroplating, producing chrome, nickel and other effects
• Aluminium alloy — usually anodised
• Brass — commonly polished or given an antique finish

Which is most durable: electroplating, brushing or spray painting?

Electroplating and brushing are more durable. Electroplating has strong corrosion resistance; brushing with a PVD coating performs well in humid environments. Spray painting looks contemporary but needs comparatively more maintenance over time.

Which finish suits which product style?

• Electroplating (mirror bright) — mid-to-high-end products, where gloss and corrosion resistance matter
• Brushing (matte texture) — understated, refined styling; wear-resistant and durable
• Spray painting (matte black and other solid colours) — modern minimalist styling, flexible colour choice, good value

How is electroplating done?

Normally in a three-layer structure:

• Copper base layer — seals the surface and improves adhesion
• Nickel middle layer — prevents oxidation and rust
• Chrome outer layer — keeps the finish bright and stable long term

Commonly applied to zinc alloy and copper substrates. Zinc alloy is highly formable and takes many surface treatments; copper substrate has few impurities and high purity, making it the ideal base for high-quality plating.

The result can be a polished mirror, matte or nickel finish, with a refined, premium feel. Commonly used on jet faces, air switches, zinc alloy handles and faucets.

Is a thicker plating layer always better?

No. More layers does not mean better quality — some products claim 5 or 6 plating layers, which may simply be masking poor substrate quality or weak casting. What actually determines plating quality is the purity of the substrate itself and the stability of the plating process: high-quality copper substrate with low impurity content is the key factor.

This is worth pressing on when comparing quotations, otherwise it is easy to be misled by layer count.

Do plated surfaces show fingerprints and water marks? Is maintenance difficult?

Mirror plating does show fingerprints and water marks, but a light wipe with a cloth restores the shine, so daily maintenance is not demanding. If your end customers are particularly sensitive to this, a brushed finish is more fingerprint-resistant.

How can I judge the quality of a surface finish?

Ask the manufacturer for acid salt spray test data. The test reflects the corrosion rate of the product in an acidic environment and is a key indicator of finishing quality. A reliable manufacturer will usually offer this data without being asked — evasion on this point is itself a signal.

How is brushing done?

The metal surface is mechanically ground to produce straight, wave or circular grain, giving a matte texture. A PVD coating is usually applied afterwards for further protection against rust, oxidation and staining.

The result is an even, fine linear grain with a high-end appearance that resists fingerprints and hides light scratches. Commonly used on jet faces, handrails and handles.

Which materials can be brushed, and is the result the same?

Brushing can be applied to 304 stainless steel and copper, with a difference in result:

• 304 stainless steel — the usual choice for premium components, but harder to process; some factories struggle to achieve a flawless finish
• Copper — easier to machine, and generally produces a finer, more refined brushed effect

What is spray painting used for?

Paint is sprayed onto the metal surface to form a protective and decorative coating. It supports a wide range of custom colours while improving corrosion and wear resistance. Commonly used on spa towel rails and spa cover lifter brackets.

What is polishing used for?

The metal surface is ground to a mirror finish. The result is highly reflective, bright and easy to clean. Suitable for metals such as stainless steel and zinc alloy, and commonly applied to jet faces, faucets, shower heads and handles.

For black shower accessories, should I choose electroplating or spray painting?

Both can produce black, with different trade-offs:

• Black electroplating — technically more demanding and more expensive
• Spray painting — multiple paint layers cured at high temperature, giving even, stable colour that resists fading and peeling, at a better cost

Spray painting is the mainstream choice for black products in volume, and suits modern minimalist styling well.

Can the colour and texture of drain fittings be customised?

Yes. Drain fittings support a range of colour and texture combinations — contact us for the detailed options.

12 questions

Can product appearance be customised?

Yes. We support custom development of product appearance, including different styles, lines and visual design directions.

What does the product design stage cover?

Three areas: appearance customization, new product technology and function customization, and dimensional specification customization.

Can new functions or technologies be developed for a single product?

Yes. We support custom development of new technologies and functions on individual products, helping customers differentiate their range.

Can component dimensions and structures be customised?

Yes. Provide the specific dimensional requirements and we will develop to them.

Is your product development limited to bathroom components?

No. Our new products now cover complete units and accessories across wellness and leisure environments, currently including sauna rooms, sauna accessories, ice baths and cold plunge tubs, with the range still expanding.

Can spa cover shapes be customised? Which shapes are supported?

Yes. Square, rectangular, round, octagonal, irregular and arched shapes are all supported, with further options available.

Is spa cover customization a core part of your business?

Yes. Spa cover customization is one of our core lines, produced by the group's dedicated spa cover factory — one of the four production units described in our Service FAQ. Contact us for detailed information.

Can you develop a product from our drawing or concept sketch?

Yes. We turn concepts into workable design solutions, provide design guidance aligned with current industry trends, and can produce preliminary designs where you do not have drawings — which removes design cost from your side.

The full path is concept and ideation → rapid prototyping and durability testing → system integration → mass production.

Can you open moulds for us? Which types are supported?

Yes. Whether a large integrated mould or a small single-part mould, we produce high-precision mechanical moulds to your design. Where tooling cost is the constraint, we also offer manual moulding, which reduces development cost substantially at lower volumes.

How long does mould development take?

Mould development is completed in 30–40 days, after which production scheduling begins. Build this period into your launch timeline.

Is there an additional charge for mould opening?

Yes. Custom moulds incur an additional tooling charge, payable by the customer, with the amount depending on mould type and complexity. Send us the product drawing or requirement description and we will quote the tooling cost separately.

Will our dedicated mould be used for other customers?

No. A customer's dedicated mould carries exclusive usage rights — we guarantee that any mould you supply or commission remains exclusive to you, is never disclosed externally, and is never used on another customer's order.

Where further legal assurance is needed, we can sign a contract setting out the terms of mould use, covering scope of use, custody responsibility and confidentiality obligations. Raise this at the tooling stage and we will prepare the agreement alongside.

2 questions

What happens if a problem appears in real-world use?

We track how products perform in actual use. Our team develops targeted improvements based on the pain points that surface in the field, and once validated, rolls those improvements out across the market as a product iteration.

In other words, the problem you report ends up improving the product itself — not just triggering a one-off replacement.

Do you have a real example of a material upgrade?

Yes. Prolonged use and extreme outdoor conditions caused the PVC bodies of air jets to age, making bubble output unstable. We launched a dedicated upgrade programme replacing PVC entirely with 304 / 316 stainless steel, which markedly improved jet stability in harsh environments, and then extended the same approach to other products with comparable material issues.

Related article: Hot Tub Air Jet Rust Solution: Product Improvement from Supplier.

Did not find your answer?

Send us your product list, target market and approximate volume, or simply photos of the parts you need. You will get a quotation within 8 hours, with specification confirmation and a compatibility check.

Contact us

About the author: Sofia compiles and maintains the Hydrorelax product and sourcing documentation. For anything not covered here, please contact us.

— End of Products FAQ —