Congratulations on a job well done! I have a similar project coming up in about 6 months together with a new house. The plans are being looked at by a structural engineer now. There will be some minor differences (Im using a single long piece of glass, Im using a swimming pool sand filter as my tank will be mainly for plants with a low fish load) but I have decided on the same type of construction. I will be getting the concrete pumped (mixing it like you did and carrying it in would have been a marathon effort!) but will be doing my own formwork and overseeing the pour.
I have two questions which Id greatly appreciate if you could answer regarding your 2500G tank:
1. How long do you have to wait after pouring the walls before the concrete has firmed up enough before you can take away the barriers and pour the floor?
2. Did you use mild steel or stainless steel snap ties (Ive heard you can get them in stainless but very pricey)?