Hydroflow Auto Top-Up Kit

Growers can leave their plants for longer and keep them fed with Hydroflow. Designed to automatically top up nutrient levels in a reservoir direct from a header tank, with no dry tanks or leaks!


– Maintain water levels on multiple systems

– Automatically tops-up and maintains nutrient levels in your reservoirs from a header tank

– Leave plants for longer and keep them fed

– Reduces growers’ labour of regular tank filling and inspection – no need to hand water

Can be attached to the following systems:

Gro-Tank, Oxypot, Wilma, Ebb & Flood, Flo-Gro, Multi-Duct

Hydroflow Auto Top-Up Kit contains:

1x Hydroflow Float Valve

1x Water Butt connector with mesh filter

1x Rubber Ring

1x 6mm Take Off

1x 1.8m (6ft) Supply Tube

Prevent Your Reservoir Tank from Running Dry!

One of the major risks with hydroponics is the reservoir tank becoming dry. If that happens (particularly if growing in clay pebbles which don’t hold huge amounts of water) then it won’t be a very long time before the root-systems of your plants dry out and foliage begins to wilt and weaken. Once that has begun to happen then roots can become damaged and vulnerable to infection. Ultimately, this impacts the health of your plants, and ultimately your final yields.

Fortunately, the Hydroflow Auto Top-up Kit will make sure that your reservoir tank is always full, combining with a water tank to give you the peace of mind that your plants are always getting the water that they need to stay healthy and productive. For more information about this product take a look at our Hydroflow Auto Top-up Kit Blog.

  • Makes sure your reservoir tank never accidentally runs dry
  • Contains an easy to fit float valve, pipe and water butt tap click-lock fitting
  • Minimises the need to check on your reservoir level
  • Simple to install – requires just a drill and a 21mm drill bit
  • The fully adjustable float valve can be fitted to the side or the top of the reservoir tank


1 x Adjustable float valve
1 x Water butt with Click-lock to 6mm piping
1 x 1.8m length of 6mm connection pipe

How the Hydroflow Auto Top-up Valve Works:

Most hydroponics systems utilise a reservoir tank from which plants are fed either constantly (as in NFT) or periodically (such as with a Wilma or IWS system). The amount of water that plants drink changes depending on their size, air temperature and the relative humidity. Regular reservoir water level checking of the level is always highly recommended, however, at times like during peak flower or in  the hot summer months even the most diligent of growers can get caught out by the plants consuming all the water. If that should ever happen, your plants will not get the water that they need, which will eventually lead to wilting, root damage and eventually death.

The ingenious Hydroflow Auto Top-up Kit allows you to create an automated reservoir tank top-up system, preventing your hydroponic reservoir from ever running dry. It contains a gland which is fitted to a header tank, a 1.8m length of piping, and an adjustable float valve which is fitted to the hydroponics reservoir tank.

When the fill level of the reservoir tank drops, the float on the float valve dips down which opens it, allowing water to flow from the header tank into the reservoir tank, topping it back up. Once enough water has topped up the header tank, the float on the float valve rises, closing off the flow of water. This ensures that the hydroponics reservoir is always topped up and that your plants never go dry. Better yet, the float valve can be adjusted so that it can be fitted either vertically (from the top of the reservoir) or horizontally (from the side of the reservoir).

How to use the Hydroflow Auto Top-up Valve:

A water butt which includes a tap needs to be installed at a level at least 15cm above the top of the hydroponics reservoir. The connection pipe that comes with the kit is 1.8 metres long, so it advisable to place it no further away than that. Drill a 21mm hole near the top level of the hydroponics reservoir. Remove the 18mm to 4mm reducer and the locking nut from the float valve but leave the rubber sealing washer in place. Push threaded part of the float valve through the hole from the inside of the reservoir and then use the lock nut on the outside of the tank to keep it in place. The float valve needs to be oriented so that the arm hangs below the threaded fitting part.

The float valve can be adjusted slightly to match the desired water level of the reservoir tank. To do this, loosen the adjustment screw at the back of the float. The float can now be moved up or down as required. When it is at the correct height, tighten the adjustment screw back up. Replace the 18mm to 4mm reducer onto the threaded part of the float valve fitting (on the outside of the reservoir tank) ensuring the rubber o-ring is in place in the inside of it first. Make sure that the lock-nut and the reducer are fully tightened.

Push the Click-lock reducer on to the outlet of your water butt and ensure that the reducer fitting is installed tightly. Connect the reducer on the float valve to the reducer on the water butt Click-lock fitting by pushing the pipe fully onto the barbed reducers. The water butt can now be filled and the float valve can be adjusted if necessary. Finally, remember to check for any leaks.