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Pro 1 Litre


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 is available in two 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.

ONA Gel is the next step up from the ONA Block and is capable of dealing with odour problems in bigger areas. Being a ‘gel’ form you can also take some of the contents of the container out and spread this around multiple areas to even better coverage. Some even choose to place the pot in-front of a fan to help cover a bigger area evenly. Remember ONA Gel is best placed in the area you are concerned you will get unwanted odours and not in the actual grow room itself.


ONA Gels 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 Gel 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:

Absorption – The smells (or volatile organic compound’s (VOC’s)) are completely retained within the compounds released by ONA Blocks.

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

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 up the entire thing. The reduced air flow over the gel will slow down the rate at which it expires.

For larger rooms and area try spreading the contents of the pot around multiple points to give even better results. You can also place a fan behind it to aid in its dispersal. Be aware that this will reduce how long it lasts.

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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