Well, when you applied the LRB/TAV you did it after one coat of the Permaflex. They specify that it be done after 2 coats. Of course, they didn't have anything to say about the emailed instructions you got stating that the LRB/TAV should be applied after one coat (post 779).
They infer that multiple layers are ok. IE Permaflex, Permaflex, LRB/TAV, then Permaflex. They had no problems with additional coats and additional applications of LRB/TAV. If Permaflex on Permaflex is ok, then how can your install be unfixable as they indicated in the email they sent you refusing your order?
Warranties are great, but if the vendor starts to change the story when problems occur then the warranty is worthless. When things go bad the true nature of the vendor is revealed.
In a way I'm glad you tried to use the Sanitred product. You were able to determine that it isn't a viable product for DIY concrete block aquariums. This saved myself and others from having to learn the hard way that this product should be avoided. That doesn't fix your problem but your pioneering is appreciated.
I'll be looking at Pond armor. I'm waiting to see how Johnptc's expansion project goes. If Pond Armor is able to seal all the joints and seams he has without a leak then I'm sold.