I bought these

https://www.lazada.com.my/products/fs-camer...7-s3346936.html

and

hygrometer (under RM20)

and RM16 airtight plastic container (20L) and few RM4 ones from mrDIY

they work very well to keep humidity very low. the gel pack comes in 4. one container 1 enough.

once the silica gels become light in color (depends on how often you open the container), just heat them up 150C at around 40minutes.