When choosing a poly cartage tank, one of the most important factors to consider is load capacity. The weight a tank can safely carry isn’t just about volume - it’s about the density of the liquid inside. That’s where Specific Gravity (SG) comes in.
What is Specific Gravity (SG)?
Specific Gravity measures how dense a liquid is compared to water. Water has an SG of 1.0, meaning any liquid with a higher SG is heavier per litre than water. If a tank isn’t built to handle the weight of a denser liquid, it can deform, crack, or fail under stress.
At Rapid Spray, our poly cartage tanks are designed to accommodate different liquid densities, ensuring safe and reliable transport.
Choosing the Right Cartage Tank for Your Liquid
1. Aqua-V (1.1:1 SG) – Best for Water & Light Liquids
The Aqua-V tank is built for liquids that are only slightly heavier than water. With a 1.1:1 SG rating, it’s ideal for water transport and other light-density fluids. These tanks range from 10L to 10,000L, making them suitable for everything from small-scale irrigation to large-volume water transport.
2. Active Liquid (1.3:1 SG) – Handles Medium-Density Liquids
Need to transport fertilisers, agricultural chemicals, or other non-hazardous liquids? The Active Liquid tank is rated at 1.3:1 SG, meaning it can handle liquids up to 30% denser than water. This makes it perfect for farmers and contractors who need a durable, reliable tank for multi-purpose liquid transport. Available sizes range from 200L to 15,000L.
Mega Molasses (1.6:1 SG) – Built for Heavy-Density Liquids
When carrying molasses, liquid fertilisers, or other dense liquids, you need a tank that won’t buckle under pressure. The Mega Molasses cartage tank has a 1.6:1 SG rating, meaning it can safely carry liquids up to 60% denser than water. Available in 1,000L to 15,000L sizes, it’s the go-to solution for heavy-duty agricultural and industrial use.
Why Does Specific Gravity Matter?
- Prevents Tank Damage – Using a tank with an SG rating too low for your liquid’s density can cause cracking, warping, or structural failure.
- Ensures Safe Transport – Overloading a tank beyond its SG rating can affect vehicle stability and increase the risk of spills or accidents.
- Extends Tank Lifespan – A properly rated tank will last longer and perform better, saving you money on repairs and replacements.
Other Poly Tank Considerations
Spray Tanks: Pin Mount, Strap Mount & Drum Rinse
For those using spray tanks, our Pin Mount, Strap Mount, and Drum Rinse models also have SG ratings, allowing them to safely carry liquids up to 1.3:1 SG, with higher SG options available on request.
Modular Tanks: Built for Large-Scale Transport
For bulk transport, Modular V1 and V2 tanks offer capacities up to 30,000L, with a 1.3:1 SG rating, making them perfect for semi-trucks and off-road tankers.
When selecting a poly cartage tank, always check the Specific Gravity rating to ensure it matches your liquid’s density. Rapid Spray’s industry-leading range provides options for light, medium, and heavy-density liquids, giving you the strength, durability, and safety needed for reliable liquid transport.
Looking for the perfect cartage or spray tank? Contact Rapid Spray today for expert advice and industry-leading solutions.
