• Easy to use.
  • Masks unwanted odours.
  • Perfect for use in home or office.
  • Cost effective odour solution
  • Natural Blend of 32 essential oils
  • Available in either 1 or 4 litres

ONA air fresheners have gained a well-deserved reputation for their long-served time in developing products to combat unwanted odours. The ONA Gel air freshener originally started as an industrial product used for freshening the air in facilities such as sewage plants. It was quickly realised the effectiveness of this product made it perfectly suitable for the indoor hydroponic market, and the hobby version that is ONA Gel was born.

Spurring a string of imitation products along the way, ONA air fresheners are still found amongst the arsenal of products in almost every hydroponic grower’s tool box. If you have a particularly noxious plant that even the hardiest of grow room carbon filters cannot deal with, or even if you feel the area could do with a nice fresh scent, ONA Gel Air freshener is the ideal solution for you.


The ONA Gel air freshener works from the combination of 32 different essential oils suspended in a gel. The crystal-like gel balls evaporate their terpenes into the air, which then begin to combat foul odours. Simply place the open container where you are having problems with bad grow room odours, open the lid and the gel will evaporate and begins to do its job! Any odours in the vicinity are completely eradicated, leaving you with a fresh smelling house.

ONA Gel air fresheners come in a variety of scents, ‘Fresh Linen’ and ‘Pro’. ‘Fresh linen’ masks and eliminates grow room smells and leaves in place the sweet scent of freshly washed clothes. The ‘Pro’ version is the most effective at removing and replacing bad or unwanted plant smells, but the smell is slightly more industrial than the ‘Fresh Linen’ version. Either one you choose; the scent is discreet and effective.

The ONA Block Air Fresheners are ideal for combating bad odours in smaller environment (like a single bedroom) or ideal to be placed throughout your extraction system, as a fail-safe to your carbon filter.  For larger areas, you may need to make use of the ONA Gel.


For best practice, place the ONA Gel containers in the environment surrounding the grow room where odours have become a problem. Alternatively, you can use them in conjunction with the custom-built ONA Breeze fans. These fans are placed directly on to the containers and actively distribute the odour killing ONA Gel throughout a much larger area. If you take this approach then you can cover a much larger area, but with an increased air flow over the gel it will evaporate faster and have a shorter lifespan as a result.

Ideally, you do not want to place these air fresheners directly near your plants. The terpenes or molecules the ONA Gel releases can react with your plant and potentially taint its usual fragrance or flavour. This is particularly crucial when/if you are drying your harvest. In drying rooms, which usually have lower amount of air movement, the direct exposure to the compounds released by the ONA Gel will have a potentially higher effect.


ONA Gel air fresheners work via the secret blend of 32 essential oils. The broad spectrum of oils work in a variety of ways to both eliminate and mask any unwanted grow room smells. As ONA Blocks use only natural, food grade ingredients they are 100% non-toxic, so health and safety issues are of minimal concern.

The essential oils work by three distinct different modes of action. This ensures that unwanted plant smells are both masked and, to a degree, removed. The three modes of action are as follows:

  1. Absorption – The smells (or volatile organic compound’s (VOC’s)) are completely retained within the compounds released by ONA Blocks.
  2. Adsorption – Similarly to how activated carbon works in filters, the unwanted VOC’s are essentially stuck onto the surface of the compounds released from ONA Blocks
  3. Chemical Reaction – Permanent bondage of the odour molecule and the active Ona Block ingredients. Particularly through the ‘Zwaardermaker Pairs Theory’, where two or more VOC’s can form a natural bond/attraction and cancel each other out.

A typical hydroponic grow room will contain plants that are creating and releasing all sorts of VOC’s, a class of which being terpenes. Terpenes and other VOC’s evaporate faster at higher temperatures, so you are likely to notice hot days being more problematic than cool ones. Terpenes and other VOC’s have a wide range of physical characteristics, so the 32 oils having these three modes of action to remove smells gives you peace of mind for a great price.


You can increase the length of time they last for by piercing holes in the lid rather than opening the entire thing. The reduced air flow over the gel will slow down the rate at which it expires.

Alternatively, to cover a large area much more effectively, use the Gel in combination with the ONA Breeze fans. A standard room fan does nearly just as good a job, simply place the open gel directly in the path of the air flow and it will be distributed over a much larger area.

Keep a few spare tubs of gel handy, when they do run out, it’s always best to be able to replace them straight away rather than waiting for the next opportunity to buy one. The risk of smells making their way out is greatly increased during that time.

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