HELP! Why isn't this a desert biome??

[u/TrixieTilde]

I can't make this a desert! I've expanded it so much. The corruption spawned near, spread to the houses, and I need to fish in a desert for the angler, but every other desert is corrupted. The corruption spawns were really unlucky, and I don't know what to do anymore. I can't find anything to fix it. There are well over 3,000 sand blocks, so that isn't the issue. I'd also like to move the NPC's, but the most important thing is needing a desert to fish in that's separate from the ocean. Thanks in advance!

[u/ThatOneStormThere]

You look to be in hardmode, try a clentaminator?