ecmp with external ip check

hello, i have configured my 450 to do LB with ecmp. i want to check if a connection is not work and i apply suggestions found on this forum:

Flags: X - disabled, A - active, D - dynamic, 
C - connect, S - static, r - rip, b - bgp, o - ospf, m - mme, 
B - blackhole, U - unreachable, P - prohibit 
 #      DST-ADDRESS        PREF-SRC        GATEWAY            DISTANCE
 0 A S  0.0.0.0/0                          212.17.192.217            1
 1   S  0.0.0.0/0                          8.8.8.8              10
 2 X S
        0.0.0.0/0                          192.168.1.1               1
 3 A S  0.0.0.0/0                          8.8.8.8                1
 4   S  0.0.0.0/0                          212.17.192.217           10 <---check-gateway
 5 X S  
        0.0.0.0/0                          192.168.10.254            1
 6 A S  ;;; Default ECMP
        0.0.0.0/0                          192.168.10.254            1 <--check-gateway
                                           192.168.1.1       
 7 ADC  10.0.0.0/24        10.0.0.1        ether9 - LAN              0
 8 A S  8.8.8.8/32                      192.168.10.254            1
 9 ADC  172.17.81.0/24     172.17.81.254   ether9 - LAN              0
10 ADC  192.168.1.0/24     192.168.1.2     ether2            0
11 ADC  192.168.10.0/24    192.168.10.2    ether4          0
12 ADC  192.168.70.0/24    192.168.70.254  ether9 - LAN              0
13 A S  212.17.192.217/32                  192.168.1.1               1

what i cannot understand well is the default route with double gateway. if i need to check an external ip with the recursive default route if a connection go down but the isp router is up, the configuration go always on the default with multiple gateway.
not the one with check-gateway.

i need the default with double gateway or i can disabile it?

Thanks