The volume of water that products are added to plays a big role in their ability to dissolve or fully disperse. The more dilute the product is before additional products are added, the greater the likelihood of successful mixing. 

In recent years the trend by manufacturers has been to increase the amount of active ingredient grams per litre included in their products. Often this is achieved by modifying or changing the surfactant system. When using a new product, or one with an increased rate of active ingredient, never assume it can be mixed with other products in the same way that similar products have in the past. Often more 

recently released products, or products with an increased rate of active ingredient, will recommend that the product is mixed into a higher initial volume of water than similar or older versions of the product. 

Care with mixing vats and handling equipment

When using a mixing vat to pre-mix products be aware of the total volume that the vat is able to hold and the amount of product that can be safely added to the vat before transferring it to the spray tank

Find out more

The GRDC publication Mixing and batching for agricultural chemical application provides more information on correct mixing when using batch mixers and what can go wrong when mixing short cuts are taken.

Many mixing vats can hold a total volume of about 1000L, whereas the total tank mix volume may be anywhere between 3000L and more than 6000L. When using a mixing vat with a total volume of less than 60 to 80 per cent of the total tank volume, do not attempt to add more than one product at a time into the vat as the total water volume in the vat will usually not be enough to allow for correct mixing. 

If the operator wants to pre-mix enough product for an entire load for the spray rig, this should be done in a tank or vessel of equivalent volume to the sprayer’s tank size. When using this type of system it may require its own agitation, and will also need a similar decontamination process to the actual spray tank and spray system.