Hi Klarrisa,
Dave Merry here from Castle Casino, I hope you are well.
To confirm, this bonus is only for new players. But you've reminded me to set-up a re-deposit bonus for Castle Casino for the Ask Gamblers members. As a thanks you can be the exception to the rule and have the 150% bonus credited to your account.
When claiming just mention that I approved this and it shall be done. Enjoy and good luck at the tables!