I was testing the mod (LargeFluidTank-2.1.jar) and built 8 wood tanks and used them to make 2 iron tanks. I loaded some liquid (creosote from IE) into one tank and piped it into an adjacent tank using an Ender IO Pressurized Fluid Conduit. When I broke the tank that received the fluid I got a game crash:

java.lang.ClassCastException: net.minecraft.item.ItemAir cannot be cast to com.kotori316.fluidtank.items.ItemBlockTank

Full crash log here: https://pastebin.com/SHBN8pLx

Now I cannot load that world at all, the game crash is repeated on load. Fortunately I always make a backup before testing a mod so I can restore it back to where it was. Please let me know when fixed... this mod looks promising!

Thank you for your report. This crash was caused by Botania. According this page, the count of new ItemStack is 0, which makes the stack empty. The method "getItem" returns Items.Air if the stack is empty. Then ClassCastException happens.
I fixed my code and checked "Greater Ring of Magnetization" worked fine.

You can find the new version, "LargeFluidTank-2.2.jar", here.