Cover story: Hi Spec 3500 slurry tanker

Spreading slurry is a key component of effective farm management. Farm Trader checks out the Hi Spec 3500 slurry tanker in action.


Based on the outskirts of Christchurch, Alistair Robinson runs a 380-hectare dairy farm, so dealing with effluent is a constant issue, hence his decision to recently upgrade to the top-spec Hi Spec slurry tanker for his operation.

Robinson Farms runs a split calving operation, peak milking 1000 cows in spring, with 700 through the winter milk contract period – something they’ve done for 25 years.

James Cochrane and Jaiden Drought discuss the rear filling options

On the further away parts of the farm, at least three cuts of grass silage are taken annually. The main job of the slurry tanker is to take the cowshed effluent further away to replenish the nutrients harvested with the silage.

An existing tanker was operating on the farm, but constant issues with the axles required a re-think. Enter farm machinery specialists Cochranes and an impressive big black Hi Spec tank. This unit ticked plenty of boxes for Alistair – low application rates, the ability to withstand constant loading five days a week, and autofill in less than four minutes (all part of the original wish-list brief for a new machine). Oh and having commercial axles, but more on that later.

The eight-inch autofill arm

Tank and chassis

Hi Spec (based in Ireland) has been in business for just over 30 years, which is a relative newcomer to the market by European standards. The likeness of conditions between Ireland and New Zealand is a useful selling point for the New Zealand distributors: Cochranes in the South Island and Giltrap Agrizone in the North Island.

Our test yoke (to get into the Irish swing of things) was the 3500 TD-S tanker: a 3500 gallon (just under 16,000 litres) tank obviously, with the TD standing for tandem axle and the S meaning standard (as opposed to the recessed option).

The inverted splash plate spreads wide and low to reduce nitrogen losses

All slurry tankers in the Hi Spec range are manufactured using high-quality six-millimetre steel with internal baffles to stop the slurry surging and causing damage while smoothing the ride for the operator.

The tanks are mounted on the large box section chassis, a key strength advantage over mounting the axle and drawbar directly to the bottom of the tank.

At the front, the chassis has a sprung drawbar as standard, using two heavy-duty springs to take all the shock transferred between the tanker and the tractor. This improves the comfort for the operator and is a relief for your spine on less-than-ideal cow races.

By spreading up to 20m, low winter application rates can be achieved

The finish on any machine is important and I’m sorry to say that not all machines are created equal, and in face some other Irish machines have been less than impressive. Fortunately, Hi Spec does not fall anywhere near that category, which given the corrosive nature of the material the machines spend their lives handling, is a real tick of approval.

Hi Spec provides a shot-blast finish to the welded tanker prior to applying the HiSpec two coat paint finish (usually in the iconic Hi Spec red), although, I’m also a fan of this distinctive black customised tanker. Customisation of the tanker colour is an option, along with alternative wheel rim colour if preferred.

An aerial view of the loading area

Pump and loading

A high-quality Jurop vacuum pump is fitted as standard across the TD-S range. Jurop pumps have a worldwide reputation for quality performance with minimal maintenance.

While I thought the pump was rather noisy when loading, it does have the exhaust mounted into the chassis, which sends the sound back under the machine. The pump is switched from suck to blow hydraulically in conjunction with the eight-inch autofill arm, which when combined with turbo filler (yet to be fitted) allows loading the 16,000-litre tank to happen in as little as three minutes.

Inspecting the load-sensing trailer brakes

For unloading, the rubber cone directs the slurry against an inverted steel splash plate to spread it out in a downward arc (which reduces nitrogen losses compared to an upward-facing splash plate). Alistair likes the 20-metre spread pattern that allows his team to cover the ground quickly and provides low application rates compared to travelling irrigators. It’s also particularly great for wet conditions.

Tyres and axles

For manoeuvrability with these larger capacities, the Hi Spec 3500 is fitted with sprung commercial axles (with the rear being steering) and fitted with 420×180 brake shoes as standard. Our test machine had both air and hydraulic brakes, allowing smoother braking, which is great for the tractor brakes, safer on hills, and reduces trailer wheels locking up.


Alistair was initially hesitant about going to the larger 16,000-litre machine (its predecessor was a 12,000-litre unit), but the efficiency of every three loads being equivalent to four with the old machine and the larger 650/55 R 26.5 tyres eased his mind.

There are a couple of key features here that are real game changers. Firstly, the rear steering axle means no scuffing at the headlands. Secondly, the big tyres have lower rolling resistance, reduced wear, and reduce the cutting out of the tracks that can get wet in the winter and obviously less pasture damage in the paddock.

The drawbar suspension smoothes the ride once the machine is full

Other features worth mentioning

  • Easy-to-see sight glass
  • Central grease bank for easy maintenance
  • Stone trap, which keeps the tank components safe and stops the rear outlet becoming blocked, given the pressure often behind the object can result in you becoming covered in effluent – not a good start to the day!
  • Heaps of lights and warning strips at the rear of the machine making it very safe on the road
  • The amount of steel, particularly in the undercarriage of this machine, is seriously impressive



The Hi Spec 3500 slurry tanker was impressive. It had a lot of clever innovation combined with the ‘add more steel’ build characteristics of the Irish machinery sector. Hi Spec certainly offers a lot of options, including dribble bars, disc injectors and rain guns. It also offers a much more stripped back version for the ‘basic’ cost-effective farmer model. This gives the flexibility of the tanker but without the massive capital expense of ‘full spec’ contractor machine, but with all the benefits of a well-designed and well-built tanker.

I like the black tanker and its clever design. It’s built to last with a serious amount of steel. The only downside is that like any effluent machine, it’s a little tricky to keep it sparkling clean.


Pump 11,000
Capacity 15,911L
Hitch Swivel
Vaccumm-pump Jurop

Suction hose

6×15 reinforced
Brake Hydraulic 420×180
Wheels 560/60 R22.5 BKT FL630


  • Well-constructed machine

  • High-quality Jurop pump

  • 8″ auto-fill allows filling the 16,000L tank in less than 4 mins

  • Large 650 tyres make very little marking on tracks and in the paddock

  • Load-sensing air and hydraulic trailer brakes

  • Easy-to-see and simple front sight glass

  • Inverted splash plate with 20m spread allows for light application rate

  • Commercial rated sprung axles with rear steering option


  • Noisy when loading (although this is due to less vanes, which also means less maintenance)

  • Tank weighs 6650kg empty. Given effluent is heavier than water means this is around 25T fully loaded. However, the large tyres help disperse this weight. 

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Photography: Justin Bennett

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