Hi Rick,
don't want to miss the opportunity and regret later.
can post some pix and details on your aerated bio reactor? I'd like to learn more on your design. I use japanese mat in my first pond but it was a pain to clean up. the stuffs sticked in and hard to get them out so I want to try out matala. plus I heard good feedbacks on matala.
as some other people already pointed out too, 2" pipe is the better way to do the draining. it's faster. the problem I have is that I have a spare 1/8 AquaFlo pump and it's only have 1.5" unions on them. I think I can do some with 2" pipe and some with 1.5" but agreed 2" is a better way to do this.
my original design has duo pumps for redundancy with shower filter and a lot more elaborated but my better half wasn't too crazy with the idea of taking too much of the tiny yard we have. in CA, duo pumps for redundancy has its limitation because we have rolling back out here so portable generator might be a better alternative.
I understand what you meant though. having duo pump is more reliable for situation such as vacation.
thank you for the feedbacks/compliments on the design,
Steve