> I will likely to get 10.10.10.10 for 1 hr,
The BigIP DNS will still return 10.10.10.10 to your query for 1 hour after the last time you checked.
> but for every 15 seconds a dns requests sends to wideip to see if the member is still active
Your system will cache the DNS result for 15 seconds, and then if you ask for that fqdn again, it will check.
Note: DNS Persistence may not always work the way you expect.
K15594: Overview of BIG-IP DNS persistence
K6082: BIG-IP DNS provides persistence records for a wide IP after a pool or data center is disabled