Describe the bug
When a Mekanism fluid tank is placed in the controller input/output slot the tank is returned before it is completely filled or emptied. The amount of fluid inserted/removed is varies based on the tier of the tank inserted, 400mb for Basic, 800mb for Advanced, 1600mb for Elite and 3200mb for Ultimate

Configuration
Mod version: 1.3.0
Forge version: 35.1.13
Minecraft version: 1.16.4
Are you playing on server?: both SP/MP

To Reproduce
Steps to reproduce the behavior:

1. Create and valid FluidSystem tank
2. Fill a Mekanism tank with any liquid
3. Insert the tank in the controller I/O slot
4. The Mekanism tank is returned with an amount of fluid inserted/removed based on the tier of the tank

Expected behavior
The tank is completely emptied or filled

Additional context
This does not happen with Pneumaticraft tanks

It's probably a problem with Mekanism, I use the Forge API and if it works in Pneumaticraft, I don't see why it's my problem.

This does appear to be an issue with Mekanism fluid tanks. I've done some testing and I've not found other tank/bucket mods that have this behavior with FluidSystem and Mekanism tanks seem to have similar issues with other mods as well. Digging through source and doing some debug work in Eclipse, I think this may have to do with Mekanism using a custom fluid handler called RateLimitFluidHandler which appears to limit transfer rates based on item tier. Closing this adding an issue on Mekanism repo.

Thanks!