The red-orange tone in the photo may be due to the influence of the surrounding light source, try adjusting the white balance. An exposure time of 30 seconds is quite long, which can cause noise and limit detail in the photo. Try reducing the exposure time to about 15-20 seconds and see what happens.
ISO 250 is quite low for night photography, ISO 400 or 800 has better brightness without overexposure. Be sure to check the lens again and make sure it is clean. Smudges on the lens can also cause areas of color noise. An remember to take the
rice purity test for relax.