Update Salt Shell Script

I have a script

#!/bin/bash
chars=( {a..z} {A..Z} {0..9} , ; . : - _ # * + ~ ! § $ % & ( ) = ? { [ ] } | > < )

function rand_string {  
local c=$1 ret=  
while((c--)); do  
ret+=${chars[$((RANDOM%${#chars[@]}))]}  
done  
printf '%sn' "$ret"  
}  
for i in {1..8}  
do  
export salt$i=$(rand_string 64)  
done  

echo $salt1  
echo $salt2  

sed -i 's/put your unique phrase here/'$salt1'/g' /var/www/testsite/wp-config.php  
sed -i 's/put your unique phrase here/'$salt2'/g' /var/www/testsite/wp-config.php  

The output I see to my screen is:

[root@server testsite]# ./salt.sh  
$,E5:2nB$p>s;2Y)h>}VU2V5Lj2UC38,yY+0?{LM;rt;Xx%B:#%9z2oc-BSE;1%Z  
~#&2#p#hZkT+)p83ZD%7=noy?§xbx%3iP4*|z<-haHXVIk<[IR0>v%.r*+X5=kNl  

However my wp-config.php contains

define('AUTH_KEY',         '$,E5:2nB$p>s;2Y)h>}VU2V5Lj2UC38,yY+0?{LM;rt;Xx%B:#%9z2oc-BSE;1%Z');  
define('SECURE_AUTH_KEY',  '$,E5:2nB$p>s;2Y)h>}VU2V5Lj2UC38,yY+0?{LM;rt;Xx%B:#%9z2oc-BSE;1%Z');  

I also tried to put the the SED statement in my loop however could not figure out how to call the variable.

sed -i 's/put your unique phrase here/'$salt$i'/g' /var/www/testsite/wp-config.php  

wp-config.php contains

define('AUTH_KEY',         '1');  
define('SECURE_AUTH_KEY',  '1');  

How can I fix this.

What i would like to see is

define('AUTH_KEY',         '$,E5:2nB$p>s;2Y)h>}VU2V5Lj2UC38,yY+0?{LM;rt;Xx%B:#%9z2oc-BSE;1%Z');  
define('SECURE_AUTH_KEY',  '~#&2#p#hZkT+)p83ZD%7=noy?§xbx%3iP4*|z<-haHXVIk<[IR0>v%.r*+X5=kNl');