why would you do that? i know a lot of people have had angels do well in higher pHs, but 8.0 is high and that should have been an issue that was considered when determining what fish to put in. a soft water, acidic species isnt exactly what should be picked for a tank that is 8.0. i dont know how long angels are supposed to live to, but i would be very surprised if this last angel that is "doing awesome" doenst end up with a considerably shorter lifespan than if it was in proper conditions.