Congrats to you for breaking 30 minutes for a mile.
I have been doing open water races every sunday on this summer and couldn't get less than 30 minutes per mile.
I started TI 8 months ago, did a weekend workshop , kept doing the drills, swimming, using the TT and improved quite a lot.
But this summer I find myself in a "plareau" I don't avance anymore. Wasn't able to break the 30 minutes per mile, 35, 32, 33...but not less than that during the whole summer time.
So Im confused about to keep with TI or change to conventional swimming trainning...
In any case congratulations again for achieving this.