Well if you want to figure out the measurements(LWH)here they are
4*4*6
The formula is principal x ( 1+ interest rate)^ number of years
5%:
20,000 x 1.05^3 = $23152.50 total
Interest = 23152.50-20000= $3,152.50
10%
20000 x 1.10^3 = $26,620.00
Interest = 26620-20000 = $6,620
12%
20000 x 1.12^3 = $28,098.56
Interest = 28098.56-20000 = $8.098.56
If i'm correct you should add 0.5 mL to your 1 gallon tank, and I would say about 1.25 mL to your 2.5 gallon. It will not be extreme if you end up putting a little more in than you are supposed to. I'm not 100% because i haven't slept so my brain is being slow.