A low hit rate indicates a high ratio of number of evictions relative to the number of keys. To resolve this issue, you need to upgrade your current subscription in order to reduce eviction.
The following example shows how to calculate the ratio of number of evictions to the number of evicted objects:
Go to My Databases > Dashboard, and look at your dashboard in the 'Day' resolution. Suppose the stats for your Redis DB are:
Total Keys: 300,121
Hit Ratio: 71.53%
Evicted Objects/Sec: 9
A rate of 9 evictions per second means that you have 9*3600*24=777,600 evictions in 24 hours, which is 2.5 times your current number of keys.