why does this mod use so much ups?
did start my Pyblock run with it and had to uninstall it bcs of lag?
not sure what's the the problem here
but when I looked at time usages this mod was the only thing in 2.xxx while all the rest be it mods or core game where at 0.xxxx

not sure if there are specific ways to use this mod so it dont go into heavy ups useage. If so pls let me know bcs i love the idea of this mod <3

To improve performance you could either increase Update Delay or decrease Water Ghosts Per Update. I recommend lowering Water Ghosts Per Update over increasing update delay since you'd still get lag with a high update delay it just happens less frequently.
The downside to that is that the mod will take longer to update WaterGhosts, so if there are a lot of water ghosts it might start taking a while for something to realize that they can convert back to normal ghosts. Also the performance impact should mostly disappear once all the ghosts have been converted back to normal ghosts/actually build so you should avoid placing WaterGhost blueprints that can never be build.
I might tweak the default for those settings in a future update, but it'll probably still take 1-2ms otherwise waterghost updates would just be to slow.

Checking whether or not every single water ghost in the map is placeable or not is pretty slow and addionally I also need to check wheter the tiles under the entity are water so I can place Ghost landfill.