1. Prodotto finitoview
The Laguna Pressure-Flo 4000 is a high-performance pressurized pond filter designed to maintain a clear, clean, and healthy pond environment. It integrates mechanical filtration with a powerful 36-watt UVC sterilizer to effectively eliminate green water and control algae in ponds up to 4000 gallons. This filter is engineered for ease of installation, maintenance, and cleaning, ensuring optimal performance throughout the season.

Image 1.1: The Laguna Pressure-Flo 4000 Pond Filter.
2. Caratteristiche principali
- 3-Step Filtration System: Combines mechanical, biological, and integrated UV filtration for comprehensive pond water purification.
- Energy-Efficient UV Bulbs: Features new four-prong UV bulbs for powerful sterilization, preventing and eliminating green water.
- Patented Backwash Cleaning System: Allows for easy and comfortable cleaning in minutes without opening the lid, prolonging time between full maintenance sessions.
- Enhanced Mechanical Filtration: Includes filter pads that are 10 times stronger than previous versions, maintaining rigid shape and performance.
- Improved Biological Filtration: Utilizes Bio-Lava rock filter media, providing increased surface areas for beneficial bacteria growth, leading to cleaner water.
- Indicatore di pulizia: An easy-to-view indicator signals when backwash cleaning is required.
- Installazione versatile: The unit can be installed either in-ground or above-ground.

Image 2.1: Clear Water Guarantee - Kills algae and eliminates green water.
3. Configurazione e installazione
3.1 Posizionamento
The Pressure-Flo 4000 filter can be installed either above ground or partially buried in the ground, depending on your pond design and aesthetic preferences. Ensure the filter is placed on a stable, level surface.

Image 3.1: Filter positioned above ground.

Image 3.2: Filter positioned in ground.
3.2 Collegamento della pompa
The Pressure-Flo 4000 is designed to operate with a solids-handling pump, such as the Laguna Max-Flo 2400 Waterfall and filter pump. Connect the pump to the filter's water inlet. Water will be drawn from the pond by the pump and directed into the filter unit.
3.3 Water Flow Path
- Water enters the filter through the water inlet.
- It then passes through the mechanical filtration stage, where durable foam filters trap dirt and debris.
- The dirt-free water proceeds to an integrated 36-watt UV-C lamp, which inhibits algae growth.
- Finally, the thoroughly cleansed water is returned to the pond.

Image 3.3: Diagram illustrating the 3-step filtration process.
3.4 Collegamenti dei tubi flessibili
The filter features universal fast couplings (PT640 x3) and a hosing connector (PT638 x1) for secure and adaptable hose connections. Ensure all connections are tight to prevent leaks.

Immagine 3.4: Es.ample of a Click-Fit Fast Connector for easy installation.
4. Istruzioni per l'uso
4.1 Avvio iniziale
After connecting the pump and hoses, ensure the filter lid is securely fastened. Plug in the pump and the UVC sterilizer. Water should begin flowing through the system and returning to the pond. Monitor for any leaks during the initial hours of operation.
4.2 Backwash Cleaning System
The Pressure-Flo 4000 features a patented backwash cleaning system that allows for quick and easy cleaning without disassembling the unit. An easy-to-view cleaning indicator will signal when the filter requires cleaning. Follow the instructions provided with your unit to activate the backwash function, which typically involves adjusting a diverter valve and rotating a handle to dislodge trapped debris.

Image 4.1: Patented Easy Clean System for convenient maintenance.
5. Manutenzione
5.1 Pulizia regolare
Perform backwash cleaning as indicated by the cleaning indicator. This process flushes accumulated debris from the filter foams, maintaining optimal water flow and filtration efficiency. The frequency of cleaning will depend on pond size, fish load, and environmental conditions.
5.2 Sostituzione della lampadina UV
The 36-watt UV-C lamp should be replaced annually to ensure effective algae control. The UVC-Head has been improved with screws permanently connected to the head, simplifying bulb replacement and preventing lost parts. Refer to the detailed instructions in your product manual for safe UV bulb replacement procedures.
5.3 Filter Foam and Bio-Lava Rock
The mechanical filter pads are highly durable, but may require occasional inspection and cleaning beyond the backwash system. Biological filtration is enhanced by Bio-Lava rock media, which provides a large surface area for beneficial bacteria. These media generally do not require frequent replacement but should be checked during deeper maintenance for excessive sludge buildup.

Image 5.1: Bio-Lava Biological Media promotes beneficial bacteria growth.

Image 5.2: The filter sponge is designed for easy disassembly and replacement.
6. Specifiche
| Caratteristica | Dettaglio |
|---|---|
| Numero di modello | PT1728 |
| Pond Capacity (Low fish load, shade) | Up to 4000 U.S. GPH |
| Pond Capacity (High fish load, direct sunlight) | Up to 2000 U.S. GPH |
| Unit Size (Diameter x Height) | 14.3" x 25.2"H |
| Altezza del contenitore | 19.7" |
| Volume del contenitore | 10.6 U.S. gal |
| Sterilizzatore UV | 36 L |
| Lunghezza del cavo di alimentazione | 16' |
| Recommended Pump | Max-Flo 2400 PT8248 |
| Filter Foams | PT1738 (x5) |
| Bio Lava | 4800 grammi |
| Universal Fast Coupling | PT640 (x3) |
| Hosing Connector | PT638 (x1) |
| Dimensioni del prodotto | Dimensioni: 40.39 x 42.67 x 68.58 cm; 14.51 kg |
| Produttore | Laguna |
| Paese di origine | Italia |

Image 6.1: Detailed specifications for Laguna Pressure-Flo models, highlighting the PF 4000 (PT1728).
7. Risoluzione Dei Problemi
7.1 Green Water Persists
- Check UV Lamp: Ensure the 36-watt UV-C lamp is functioning. UV bulbs lose effectiveness over time and should be replaced annually.
- Verify Pond Size: Confirm the filter capacity matches your pond size, especially considering fish load and direct sunlight exposure.
- Perform Backwash: The cleaning indicator may signal a need for backwash. Regular cleaning is crucial for optimal performance.
7.2 Flusso d'acqua ridotto
- Controllare la pompa: Ensure the pond pump is clean and operating correctly. A clogged pump can restrict flow.
- Ispezionare i tubi flessibili: Look for kinks or blockages in the hoses connecting the pump to the filter and the filter to the pond.
- Clean Filter Foams: Perform a backwash cycle. If flow remains low, a more thorough manual cleaning of the filter foams may be necessary.
7.3 Leaks Around Connections
- Stringere le connessioni: Ensure all hose connections and the filter lid are securely tightened.
- Inspect O-Rings/Gaskets: Check for damaged or improperly seated O-rings or gaskets at connection points and the filter lid. Replace if necessary.
8. Garanzia e supporto
8.1 Informazioni sulla garanzia
For specific warranty details, please refer to the warranty card included with your product or visit the official Laguna websito. Conservare la prova d'acquisto per eventuali reclami in garanzia.
8.2 Assistenza clienti
If you encounter any issues not covered in this manual or require further assistance, please contact Laguna customer support. Contact information can typically be found on the product packaging or the manufacturer's websito.