Milk tanker last use liquid fertilizer

[adironmaple]

Went to a farm auction the other day that had a 4000 gal milk tanker. Well I bought it for a reasonable price. We are row crop farmers as well as sugarmakers and my first thought is to use as liquid fertilizer storage as we need to replace an old poly 3k tank. But was wondering if there is any way it could be professionally cleaned to be used as sap storage. We are adding approx. 3000 taps at one location so it could work there if it could be brought back to food grade. I don't know much about this subject and would'nt want to compromise, in any way, the other 20,000 taps we run! TIA

[n8hutch]

While I haven't Done this Myself I would think if you cleaned the Tank good, then filled it with water and let it sit a Few Days weeks, and took a water Sample and had it tested I think the Tank would be Fine, biggest places of concern would be plumbing connections, seals, gaskets, places where things can be caught in them, there are lots of people using repurposed stainless Tanks such as old firetruck tankers and I am certain that they cant know for sure w/o a doubt what was in it.

What is the chemical makeup of liquid fertilizer?

[buckeye gold]

I'd be very suspect of that getting back to food grade. Residues are really hard to eliminate. You can't even get them off glass completely unless you acid wash it. I used to do a lot of wet lab work and I was astonished how much residue would remain in our sample containers. We'd fill them with distilled water and check and would find traces of compounds. It usually took a double acid wash to get them really clean.