# Tank mix checklist: permissions, compatibility and loading URL: https://leafwrit.com/uk/pesticide-tank-mix-checklist/ Reviewed: 2026-10-29 A **tank mix** is two or more plant protection products (PPP) mixed in the spray tank and applied together. It is allowed as long as it is within the conditions specified on each label and no label carries a specific restriction against that particular mix. ## Write down the combination first Copy the full trade names and registration references from the containers or current documents. Note the crop, the timing, the application method and the reason for mixing. Give your adviser the original recommendation to check against. ## Which tank mixes are not allowed Two kinds of tank mix are unacceptable. First, two or more anticholinesterase compounds, unless the authorised conditions of use on the label of at least one of the products specifically allow the mixture. Second, acetolactate synthase (**ALS**) herbicides, including sulfonylureas, in tank mixture or sequence with other ALS herbicides, unless the product label says otherwise. Mixing anticholinesterase compounds without that permission is illegal (and possibly unsafe). So is using an adjuvant that is not on the authorised list. ## Roundup (glyphosate) mixed with ammonium sulfate, 2,4-D, MCPA and dicamba There is no separate rule for a glyphosate (Roundup) mix with 2,4-D, MCPA, dicamba or ammonium sulphate. The general rule decides: users can apply any convenience tank mix so long as the authorisation does not preclude mixing with other products or specific products. Where the authorisation of any partner, or its label, rules out that mix, it is not allowed. ## Moddus, Pixxaro and other named products The rule for a Moddus or Pixxaro tank mix is the same as for any other product: the conditions on the label of every partner must be met. For Pixxaro, Corteva describes broad compatibility with a wide range of tank mix options, including fungicides and ACCase graminicides for grass weed control. For Moddus itself, the Syngenta label gives the mixing routine: fill the spray tank with half the required volume of clean water and start agitation, add the required amount of Moddus, then keep agitating while the rest of the water goes in. The mixture is agitated thoroughly before use and the agitation continues during spraying. The label sets out how Moddus is mixed and sprayed, and it does not name tank-mix partners, so a mix with a fungicide or another growth regulator still comes down to the label of that partner and the manufacturer's recommendation for the combination. Moddus is a plant growth regulator (MAPP 15151), and its safety data sheet lists no known incompatible materials, which is a statement about the product itself and not a clearance for any mix. ## Tank mixing fungicides, insecticides and herbicides A convenience tank mix combines products to reduce the number of spray operations; it is done when the right application timing of each product coincides. A positive tank mix gives better pest control than the products applied alone, for example to control additional pests or to reduce the rate of one of the products. The same rules cover a fungicide and insecticide mix, a fungicide and herbicide mix, and a mix with an adjuvant. ## Compatibility: what must be proven A convenience mix must be shown to be physically and chemically compatible. A positive mix must also be biologically compatible (effective and crop-safe). Any convenience tank-mix recommendation, whether on the label or given by the authorisation holder verbally, on websites or in advertising, must be supported by physical and chemical compatibility data; the ASTM standard method is E 1518-05. This covers a recommendation from BASF, Yara or any other manufacturer. A Compatibility Assurance Statement (CAS) certifies that data or evidence is available to show the products in the mixture are physically compatible. The label's compatibility section may also name mixes known to be incompatible and give specific mixing instructions. If compatibility is unclear, check the compatibility information on the product label and get further guidance from your adviser, supplier or the product's manufacturers. When you ask, give the exact product names and the intended use. Keep the answer with the job papers, together with its date and the products it covers. If a question is still open, write it down and settle it before you prepare the loading instruction. ## Water volume, spray quality and timings For a tank mix, the intended volume of water and the spray quality must be in line with the recommendations for each product, and all other conditions of use of the individual products, such as application timings, must be met. ## Loading order Before loading, give the loader and the applicator the same written instruction and the same label documents. Add the products one by one to the spray solution in the order recommended on the product labels, following any specific mixing instructions such as the amount of water in the tank when each product is added and the stirring or shaking needed. If a label gives no order, add the product types in this order: water-soluble bags; water-dispersible granules (or soluble granules); wettable powders (or soluble powders); suspension concentrates; emulsifiable concentrates (or oil in water emulsions); and finally adjuvants. Add pesticides to water separately (except some "twin-pack" products). Do not mix two or more concentrates before or at the same time as loading them into the tank. When pesticides go on with other chemicals, follow the labels of all the relevant products and use all the information the supplier provides. Watch for an increased risk of foaming and for blocked nozzles and filters. ## Mixing and loading rules If a different person mixes and loads, make sure the person applying has read and understood the product label (ideally with a copy). Measure out powder and fine granules in sheltered conditions so fine particles do not blow away. Do not prepare spray solution in bulk for more than one user unless the equipment needs no alteration to suit individual users (such as stump treatment bottles and spot guns) and the solution needs no constant stirring or shaking. Have a spill kit available at all times and know how to use it. Never try to hose down a spillage. ## Fill the tank without backflow, overflow or foam Do not make a direct connection between a water supply and the spray tank; use an intermediate tanker or system to prevent pesticide being drawn back. Do not take water straight from a stream, other watercourse or pond. Pay close attention to the level of the tank contents while filling (a fill-level alarm, flow meter or pre-set shut-off valve helps). Never leave the sprayer unattended while filling. Avoid foaming by using appropriate induction, stirring or recirculating systems and by fixing leaks in the suction system; use an antifoam or defoamer if necessary. Do not shake or stir the product too much or add foaming products too early. Make sure valves are correctly re-set after using an induction bowl. ## Do not add a product to a job already under way Do not add a product just because there is room left in the tank. A changed combination needs the same check as the original one: the remaining crop, each label's conditions and the compatibility evidence. Leave that decision to the person responsible for the use decision. If the area or the load changes, redo the calculation and keep it with its inputs, rather than leaving several unexplained totals on the work order. ## Operator and environmental protection Protection (engineering controls and PPE) must reflect the highest obligations stated on the product labels and any extra needs from the COSHH assessment. Measures to protect wildlife and the environment, such as buffer zones, must reflect the highest obligations on the labels and any extra needs from the environmental risk assessment. ## Manufacturer recommendation and applicant statement Authorisation holders may include specific tank-mix recommendations on the product label or in other literature, and then data must be available to demonstrate physical/chemical compatibility and in some cases biological compatibility (efficacy). ## Anti-drift spray additives, spreader stickers and surfactants: check the ADJ entry Check each additive you plan to use, whether a carrier, a fertiliser or a marker, against the mixing restrictions on the pesticide label. A substance or preparation supplied to be mixed by the user with a plant protection product, and which enhances its effectiveness or other pesticidal properties, is an adjuvant. Adjuvants are not plant protection products, but they are subject to regulatory control. A pesticide spreader sticker or a surfactant used in agriculture is an adjuvant when it is supplied to be mixed in the tank to enhance effectiveness. The **Official List of Adjuvants** gives the adjuvant products that may be used with plant protection products and their conditions of use. Each list entry specifies the identity of the adjuvant, including its ADJ (registration) number, and only one list entry is extant for each product at any time. The adjuvant's conditions of use are in addition to the conditions on the pesticide label. A pesticide may be used with an adjuvant only if the adjuvant appears on the authorised list and the use is in line with both labels. ## Herbicide marker dye A dye that colours the water or the leaves does not show that the mix is compatible or permitted, and it does not measure the herbicide dose. Check delivery with nozzle output and the treated area, and note the marker colour separately. Use the marketed product itself, not a household colouring. Do not pre-mix a pesticide concentrate with an adjuvant, carrier, marker or any other material unless the approved conditions of use of the pesticide allow it and an appropriate COSHH assessment has been carried out. ## Next step Retrieve every partner's [product documents](/uk/hse-gb-pesticides-approval-register/), then use the [tank-mix calculator](/uk/spray-tank-mix-calculator/) with the checked rate, water volume and treated area. Delivery rate comes from [measured nozzle output](/uk/sprayer-nozzle-chart/) and the [knapsack calibration sheet](/uk/knapsack-calibration-sheet/).