Operation and Maintenance Manual: Underwater Windows

General Information and Scope

Hydrosight manufactures a wide range of products for various applications, including swimming pools, aquariums, and research tanks. The specific maintenance and care requirements depend on the installation site, climatic conditions, and water load.

A fundamental distinction is made between two types of glazing, for which different care instructions apply:

• Laminated Safety Glass (LSG)
• PMMA Block Material (Acrylic).

Protective Measures During the Construction Phase

Each window element is delivered ex-works with 3 mm thick white protective plates on both the dry and wet sides.

• Protective Function: The plates provide mechanical protection against impact and thermal protection against material expansion caused by direct sunlight.
• Duration: The covers must not be removed during the entire construction phase, including water tests or temporary filling. The construction phase is considered complete only upon the official start of use by the owner.
• Liability: The customer bears the risk for any damage resulting from the premature removal of the protective plates.
• Recommendation: It is recommended to keep the protective plates for later maintenance work (e.g., when draining the pool).

Cleaning the Glazing

Acrylic (PMMA) – Dry Side

• Regular Cleaning: Cleaning should be performed with a soft, lint-free cloth or sponge (e.g., microfiber), moderately moistened with water.
• Warning: The material must never be rubbed dry, as the plastic will become electrostatically charged and attract dust, leading to scratches.
• Intensive Cleaning: For greasy soiling, use mild cleaning agents (without scouring agents) or benzene-free benzine (white spirit/washing benzine).
• Prohibited Substances: Cleaning agents containing benzene, ethanol, alcohol, or organic thinners attack the PMMA structure and must not be used. Never use standard alcohol-based glass cleaners, as these can cause stress cracks.
• Pre-treatment: Coarse dirt particles must be rinsed off beforehand with plenty of clear water.

Acrylic (PMMA) – Wet Side

• Degree of Soiling: The water side is generally less prone to soiling; deposits rarely occur in chlorinated pools.
• Algae Removal: In aquariums, algae can be removed mechanically using a window squeegee (e.g., Unger Monsoon Strip Pac). Chemical additives are not required.
• Detail Cleaning: A microfiber cloth is recommended for corners and smaller areas.
• Automated Cleaning: Pool robots can damage the acrylic glass. Only models classified as safe by the manufacturer (no hard brushes/rollers) may be used.

Laminated Safety Glass (LSG)

There are no specific restrictions for cleaning LSG compared to standard building glass surfaces.

Treatment of Adjacent Areas and Chemical Influences

Caution is required when cleaning the pool surroundings (e.g., stainless steel surfaces).

• Hazardous Substances: Standard stainless steel cleaners often contain phosphoric acid, nitric acid, and surfactants. These must not come into contact with the glazing or the joints.
• Protective Measures: If such cleaners are used over large areas, the windows must be protected using the cover plates.
• Joint Protection: Silicone seams should be protected with approx. 50 mm wide, solvent-free tape with limited chemical resistance (e.g., 3M™ Protective Film 3103H).
• Verification Duty: PMMA is resistant to conventional swimming pool chemicals. If chemicals other than standard pool water come into contact with the pane, chemical resistance must be verified with the manufacturer in advance.

Operating States: Draining and Emptying

The window is designed for permanent use under water load ("filled pool"). A dry state represents a special condition requiring specific safety measures.

• Protection Against Impact Loads: Since the static counter-pressure of the water is missing when the pool is empty, the area in front of the panes on the dry side must be secured against impact loads (e.g., from persons or cleaning machines).
• Thermal Load: When the pool is empty, heating due to direct sunlight on the acrylic panes must be avoided at all costs (risk of overheating and thermal expansion). It is recommended to reattach the original white protective plates.
• Climatic Conditions: The air temperature must remain within the permissible range; rapid temperature changes must be minimized.
• Duration: The dry period should be kept as short as possible.

Repair (Polishing)

Acrylic (PMMA)

Scratches may occur due to improper handling or in high-traffic public areas.

• Self-help: Light surface scratches can often be polished out. This may only be done using suitable polishing pastes (e.g., QUIXX System Acrylic Scratch Remover).
• Professional Repair: Deep scratches or structural damage require assessment by Hydrosight.

Laminated Safety Glass (LSG)

LSG is very resistant. However, should scratches occur that impair the optical quality, the glazing usually needs to be replaced.

Maintenance and Inspection

Hydrosight products are designed to be low-maintenance. However, regular visual inspections are required to ensure permanent operational safety.

Inspection Criteria and Warnings

The panes must be visually checked for the following features:

1. Surface: Scratches, haze/cloudiness, or crazes (fine networks of cracks).
2. Color: Strong discoloration of the material.
3. Seals: Condition of the silicone seams (detachment, cracks).

WARNING: We urgently advise against attempting to make cracks visible using crack testing sprays or solvents, as these substances can trigger stress cracks in PMMA. If abnormalities are detected, the manufacturer must be contacted immediately.

Maintenance Intervals for Critical Applications

For applications with increased risk (personal injury in case of failure, public facilities), Hydrosight recommends:

• 2.5 Years after Installation: Visual inspection by the customer or a qualified expert.
• 5 Years after Installation: Inspection by Hydrosight (after expiration of the warranty). This includes O-ring replacement, leak testing, and cosmetic repairs. Upon approval, fitness for use is extended by 2.5 years.
• Recurring: Further maintenance takes place in the same cycle (7.5 years, 10 years, etc.).

Contact

Hydrosight GmbH
Dechant-Sprünken-Str. 51A
46446 Emmerich
Germany

Phone: +49 28 22 60 250 90-0
Email: io@hydrosight.com