When you get to the target, study the test 700 ways. This is about the only time you'll ever have an exactly known end result starting with 0. Your rectangle pool is easy to get right for volume, (some folks have difficulty with the lagoons/kidneys), so whatever you see once this is balanced, repeat that view forever. Get the hubs involved for his eyes. Teach the kids. All of you will know what your test looks like in your pool. Everyone should be so fortunate
Also, did we tell you that you can reuse this sample over and over ? Suck it back up and repeat as many times as necessary. Everybody has their comfort level..... 2 out of 3, best of 5, etc.