Backyard Aquaponics
A place to discuss aquaponics

You could always use slipform technique!
But you would have to brace the inside.

my local hardware store charges nearly $30 for a 94# bag of king king ready mix. But they have a captive market, it's 40 miles to town to the nearest home depot or others.

What type of a paint or sealer would you use? And wouldn't you have to wait for the cement to fully cure or it would blister?

yep 21 days, or out gassing would blow bubbles in ya coating!

What would this be?

Pretty much as it sounds. basicly you slip the form as you go.
Bit of ginning around but it does the job.
aside - am upgrading to 6.o ATM about 20 mins.
o oh no, think I should find a good site discription or I will be here all night ! no offense intended just the way i go about discribing things.

http://www.seovic.com.au/civil/gallery/ ... walls8.htm

you may get the idea from these pics.
Not quite the same but similar technique.