Inspect Farm Poly Tanks
Dr. Fred Whitford, Purdue University, has provided some research in the area of farm poly tank longevity. He recommends taking a baseball bat to your empty farm poly tank this spring prior to using your tank this year. Many of the poly tanks used for transporting pesticides and fertilizer can be quite old, and poly tanks are not meant to last a lifetime. In addition, some tanks may be used for pusposes which they were not desinged. For example, it is very common to see vertical storage tanks strapped to a flatbed and transported. Vertical storage tanks are not designed for transport, and this presents a risk especially if that tank is carrying fertilizer or pesticide.
Dr. Whitford also recently released a very nice publication with pictures and demonstrations about this topic. The publication is available online from Purdue at: https://secure.agriculture.purdue.edu/store/item.asp?itemID=18824
After hitting the empty tank with a baseball bat, inspect the tank visually. If the tank splits or cracks, it is obviously not suitable for use this spring. After striking the tank, one should take a water soluble pen (dry erase marker) and cover the area with ink where the bat impacted the tank. Immediately wipe the area with a cloth rag. A tank that is still in good shape will not show crazing (a checkered pattern) where the impact occurred.
When replacing your poly tank, there are several factors to consider. First, pay attention to the density rating. Poly tanks come in three density ratings: 1.0, 1.5 and 1.9. A 1.0 density tank is rated equal to the pressure exerted by water whereas a 1.9 density tank is would be rated to withstand 1.9 times the pressure exerted by water. A 1.5 or 1.9 rated density tank should be used when the tank will be utilized for transport. Another consideration is use of the tank. If the tank will be used for transport, the tank should be baffled appropriately.
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