Nothing can remove the creative portable tanks, in singleplayer i found 3 wrenches that worked: Crescent Hammer, Multiblock fluid tank wrench, flux-infused Omniwrench but neither of those work on the server, block breakers dont work either
Are the tanks in a claim? Does this issue happen outside of a claim? This sounds like a permission issue, but it might not be.
john01dav cant remove them anywhere
Going to close this as it's a pack issue and there's not much we can do to fix it. I would suggest relaying this to the pack devs via their Discord and/or issues page on GitHub.
If you have any that you've placed, but you can't break and want removed, let us know.