2ISP with balancing - how to redirect speedtest.com to use only ISP1

hi gurus,

I have 2 ISP and load balancing is already done with mangle in V7 mikrotik.
I wanted to all users on the network when they want to access a particular website or run a speedtest like speedtest.net and fast.com to always go to or passthrough ISP1 only. hope someone can help thanks in advance.

Most easy would be through an address list which resolves the DNS-es of the desired sites to IPs, mangle and routing table:

/ip firewall address-list
add list=client_sites address=speedtest.net

/ip firewall mangle
add action=mark-routing chain=prerouting dst-address-list=client_sites new-routing-mark=client_traffic

/ip route 
add dst-address=0.0.0.0/0 gateway=ISP1_gateway routing-mark=client_traffic