Dincel forms are $25 per meter110mm and $28 meter 200mm plus delivery.
7.5x3.5x 1.5 average pool will require 100 meters @say $25= $2500 because of design they require more concrete than blocks as well and tiling is required they must be prepared with an approved coating so the cost adds up quite alot will most likely go down the raod using versaloc bricks and cement render/paint.
Steel will be from onesteel using 12mm pool bar. i work for them so an easy choice.
I have looked at thermaell but was worried about internal finish being damaged.