Cooltube Kit 125 mm – Complete Grow Light Set for Temperature Control

The Cooltube Kit 125 mm is the definitive weapon for growers who refuse to let heat ruin their harvest, offering a complete lighting system that actively cools the bulb to keep your climate perfect. Unlike standard reflectors that radiate heat downwards onto your canopy, this tubular design traps the heat and uses your air extraction to remove it immediately, giving you the power to maximize light intensity while maintaining a cool, safe environment for your plants.

Are you tired of fighting a losing battle against the thermometer in your grow tent?

We know the feeling: you check your indoor setup, and the temperature is spiking above 28°C. You raise the lights, but now they are too far away, and your plants are stretching. It feels like you have to choose between burning your crop or getting airy, weak buds. This lack of control creates constant anxiety, making you feel like you are just "winging it" rather than managing a professional grow, especially during the hotter months.

If you don't solve this, the consequences are frustrating. Heat stress stops plant growth, evaporates terpenes, and invites pests like spider mites that thrive in hot, dry conditions. You end up stressing yourself out, constantly adjusting fans and AC units, watching your electricity bill soar while your yield quality drops. It turns a relaxing hobby into a source of daily stress.

The Cooltube Kit 125 mm is the tool that hands you back the controls. By enclosing the bulb in a glass tube connected to your Air Extraction System, the heat is sucked out before it ever touches your plants. This allows you to maintain the perfect temperature range effortlessly, giving you the peace of mind that your environment is safe, stable, and optimized for massive production.

More discretion, fewer worries

When we talk about discretion, we often think of smell, but heat is also a major factor. A grow room that leaks excessive heat can be a red flag, and managing it often requires noisy fans running at 100% capacity. The Cooltube design helps you run a stealthier operation by attacking the heat at the source.

Because the bulb is enclosed in high-resistance glass, the thermal footprint of your lighting system is drastically reduced. This means your extraction fans might not need to work as hard to maintain the ambient temperature, resulting in less noise and vibration. It allows you to fit a powerful HPS light into a smaller wardrobe or tent where a standard reflector would turn the space into an oven.

Furthermore, the safety factor is huge. The glass barrier protects your plants (and you) from accidental contact with the hot bulb. It adds a layer of security to your setup, ensuring that even if a plant stretches a bit too much, it won't immediately fry against the lamp.

Control over the experience

• Closer Proximity: You can place the light much closer to the canopy (20-30 cm) without burning tips, increasing the lumens your plants receive.
• Temperature Management: Lowers the temperature at the plant tips by several degrees compared to open reflectors, essential for Climate Control.
• Versatility: Compatible with both HPS (flowering) and MH (growth) bulbs, giving you control over the entire cycle.
• Space Optimization: Its cylindrical shape is perfect for narrow spaces or arranging multiple lights in a line without creating hot spots.
• Durability: The glass is designed to withstand high temperatures and drastic changes, ensuring a long lifespan for your kit.

How to use it responsibly and comfortably

Setting up the Cooltube Kit 125 mm is straightforward, but doing it right ensures maximum efficiency and safety. Follow these steps to integrate it into your routine:

1. Prepare the Circuit: Install your extractor fan and carbon filter. The airflow should go: Filter > Ducting > Cooltube > Ducting > Extractor > Out.
2. Hang the Reflector: Use easy-roll pulleys to hang the Cooltube. Ensure it is level and secure.
3. Install the Bulb: Screw your HPS or MH bulb into the socket inside the tube. Important: Use a clean cloth to hold the bulb; never touch the glass with your bare hands as oils can cause it to burst.
4. Connect the Air: Attach the 125mm aluminum ducting to both ends of the Cooltube and secure them with metal clamps to ensure it is airtight.
5. Power Up: Connect the reflector cable to the ballast, and then plug the ballast into the wall (preferably through a timer).
6. Check the Flow: Turn on the extractor and check that air is being pulled through the tube before turning on the light.

Benefits of having everything under control

• Summer Growing: You can keep growing high-quality weed even when the weather outside gets hot.
• Denser Buds: Because the light is closer, light penetration is deeper, resulting in harder flowers further down the plant.
• Less Stress: No more panic when you open the tent; the climate remains stable.
• Efficient Nutrient Uptake: Plants transpire better at the correct temperature, absorbing more water and nutrients.
• Extended Bulb Life: Active cooling can help your bulbs maintain their spectrum efficiency for longer.

Frequently Asked Questions

Can I use the Cooltube without an extractor?

No, it is not recommended. The Cooltube is designed to have air passing through it. Without extraction, heat will build up inside the glass tube, potentially damaging the bulb or the socket.

Does the glass reduce the light intensity?

The glass used is high-quality and transparent, with minimal light loss. The benefit of being able to move the light closer to the plants far outweighs the tiny percentage of light absorption by the glass.

What size tent is this kit for?

This 125mm kit is versatile. It fits perfectly in Grow light kits setups for tents ranging from 80x80cm to 120x120cm, depending on the wattage of the bulb you choose (400W or 600W).

How much does it lower the temperature?

While it depends on your overall ventilation, a Cooltube can typically lower the temperature at the canopy level by 3°C to 5°C compared to an open reflector.

Personal Experience of Pevgrow’s CEO (Alan)

I'll be honest with you: before I switched to Cooltubes, I used to shut down my indoor grow during July and August. It was just impossible to manage the heat here in Spain without turning my grow room into a sauna. This kit changed that for me. It gave me back control over my calendar, allowing me to harvest year-round without sacrificing quality.

My personal trick? I set up the extraction to pull air directly from outside the room (if it's cool enough) through the Cooltube and straight out a window, creating a closed cooling loop that doesn't even touch the air inside the tent. This keeps the smell 100% contained inside the tent while the bulb stays ice cold. It’s the ultimate setup for peace of mind.