usually you would want a pump that could circulate the amount of water you have every hour so you would need a pump for 13000 gph but that's a substantial amout so if you could even find a pump that pumps half of that an hour you should be alright
LxW
That depends on the size of each unit.
A small sand filter 40-60 sq ft. and a small pump 3/4 HP
13000L = 2,859.6 gallons AU
3 percent of 13000 = 3903% of 13000= 3% * 13000= 0.03 * 13000= 390
3% of 13000 = 3% * 13000 = 0.03 * 13000 = 390
10% off 13000 = 13000 - (0.1 x 13000) = 11700
169,000,000
45% of 13,000= 45% * 13000= 0.45 * 13000= 5,850
13000
195015% of 13000= 15% * 13000= 0.15 * 13000= 1950
5% of $13000 = 5% * 13000 = 0.05 * 13000 = $650