Please help me with your expert advice on porn blocking

Hi

I have just setup Open DNS and it is blocking porn sites. However I can still see pics of hot girls in Google images. Still a great start!

• I am using open dns family shield, I did not need to sign up
  • Perhaps I should sign up with the open DNS home? Can I then select which sites I would like to block - for example, take advantage of the open DNS
    
  • Should I create an email addy and give that and the password to a friend?
  • Pls note, I plan on updating router password and emailing that to a friend
    
  • Can the open DNS home package be configured to block sites, for example escort sites (I like the pics, never used it but it is a slippery slope I am sure!)
• I have looked at tools like k9, however, I have access to 4 computers and more devices, so I want a network level protection.
  
• What is best smartphone blocker for android
• What is best blocker app for ipad?

 

Update

These are the Operating systems I have / have access to.

PC - dual boot - Windows 7 / Ubuntu 16.04
Lappy 1 - Mint (mine)
Lappy 2 - Windows 7 (wifes old one)
Lappy 3 - Windows 10 (wife's)
Device 1 - Ipad (family)
Device 2 - My phone
Device 3 - Wife's phone (surely I wouldn't )

Some of the content filtering tools I have seen (k9 - sophos) do not work on Linux, I may need to search linux specific tools.

 

I got this list, I will sort out the Linux stuff and try k9 or something similar for the windows.

http://www.techradar.com/news/software/applications/6-of-the-best-content-filters-for-linux-698307/3