MS SQL Server 2008 R2 Performance - Reconfigure

Hi Techies,

    First of all, thank you all for replying my question.

Environment - Production:

     MS SQL Server 2008 R2 installed in Windows 2008 server 64 bit (Dedicated) (Installed memory 28GB). This DB is replicated to three more physical read only servers & this primary DB is connected to 8 web servers which are in load balancing.

Current Scenario:

     After SQL server in action for some time (Variable) there is a shoot up of memory in the windows server. please find the screen shot below,

     I am very sure this is not because of memory leaks & it is cache stored.

Resolution:

     I implemented the below code & scheduled a job which runs in a interval and flushes the unused memory. This in-turn brings down the memory to considerable GB. Please find the code below,

     ---------------------------------------------------------

     sp_configure 'show advanced options', 1;
     GO
     RECONFIGURE;
     GO
     sp_configure 'max server memory', 4096;
     GO
     RECONFIGURE;
     GO
     WaitFor Delay '00:00:45'
     GO
     sp_configure 'max server memory', 24576;
     GO
     RECONFIGURE;
     GO

     ---------------------------------------------------------

     This was been running successfully for past three years without any issues.

Question:

    1) Is this right approach to do ?
    2) Pros & Cons
    3) Leaving cache at high value is normal ?
    4) Any other alternate solution ?

With Best Regards,

Karthik