Before we wrap up this year's repeat on this subject, for the benefit of those not yet convinced, let's look at the impact of doing 10% weekly water change. Assume that your feeding regimen, natural leaf-input etc. results in 10 units of water pollution per week. You have condemned your koi to a year of deteriorating conditions. Huh???.... Perhaps the following will help you think through it.
Week 1: 10 units of pollution, less 1 unit per 10% water change, leaves 9 units in the pond.
Week 2: 9 + 10 = 19 pollutant units, less 1.9 per 10% water change, leaving 17.1 units.
Week 3: 17.1 + 10 =27.1, less 2.7, leaving 24.4 units.
Week 4: 24.4 units + 10 = 34.4, less 3.4, leaving 31 units of pollution.
Week 5: 31 + 10 = 41, less 4.1, leaving 36.9 units.
Week 6: 36.9 + 10 = 46.9, less 4.7, leaving 42.2 units.
Week 7: 42.2 + 10 = 52.2, less 5.2, leaving 47 units.
Week 8: 47 + 10 = 57, less 5.7, leaving 51.3 units.
Week 9: 51.3 + 10 = 61.3, less 6.1, leaving 55.2 units.
Week 10: 55.2 + 10 = 65.2, less 6.5, leaving 58.7 units
Week 11: 58.7 + 10 = 68.7, less 6.9, leaving 61.8 units.
Week 12: 61.8 + 10 = 71.8, less 7.2, leaving 64.6 units.
Week 13: 64.6 + 10 = 74.6, less 7.5, leaving 67.1 units.
Week 14: 67.1 + 10 = 77.1. less 7.7, leaving 69.4 units.
Week 15: 69.4 + 10 = 79.4, less 7.9, leaving 71.5 units.
Week 16: 71.5 + 10 = 81.5, less 8.2, leaving 73.3 units.
Week 17: 73.3 + 10 = 84.4, less 8.4, leaving 76 units.
Week 18: 76 + 10 = 86, less 8.6, leaving 77.4 units.
Week 19: 77.4 + 10 = 87.4, less 8.7, leaving 78.7 units.
Week 20: 78.7 + 10 = 88.7, less 8.9, leaving 79.8 units.
Week 21: 79.8 + 10 = 89.8, less 9, leaving 80.8 units.
Week 22: 80.8 + 10 = 90.8, less 9, leaving 81.8 units.
Week 23: 81.8 + 10 = 91.8, less 9.2, leaving 82.6 units.
Week 24: 82.6 + 10 = 92.6, less 9.3, leaving 83.3 units.
Week 25: 83.3 + 10 = 93.3, less 9.3, leaving 84 units.
Week 26: 84 + 10 = 94, less 9.4, leaving 84.6 units.
Week 27: 84.6 + 10 = 94.6, less 9.5, leaving 85.1 units.
Week 28: 85.1 + 10 = 95.1, less 9.5, leaving 85.6 units.
Week 29: 85.6 + 10 = 95.6, less 9.6, leaving 86 units.
Week 30: 86 + 10 = 96, less 9.6, leaving 86.4 units.
Week 31: 86.4 + 10 = 96.4, less 9.6, leaving 86.8 units.
Week 32: 86.8 + 10 = 96.8, less 9.7, leaving 87.1 units.
Week 33: 87.1 + 10 = 97.1, less 9.7, leaving 87.4 units.
Week 34: 87.4 + 10 = 97.4, less 9.7, leaving 87.7 units.
Week 35: 87.7 + 10 = 97.7, less 9.8, leaving 87.9 units.
Week 36: 87.9 + 10 = 97.9, less 9.8, leaving 88.1 units.
Week 37: 88.1 + 10 = 98.1, less 9.8, leaving 88.3 units.
Week 38: 88.3 + 10 = 98.3, less 9.8, leaving 88.5 units.
Week 39: 88.5 + 10 = 98.5, less 9.9, leaving 88.6 units.
Week 40: 88.6 + 10 = 98.6, less 9.9, leaving 88.7 units.
Week 41: 88.7 + 10 = 98.7, less 9.9, leaving 88.8 units.
Week 42: 88.8 + 10 = 98.8, less 9.9, leaving 88.9 units.
Week 43: 88.9 + 10 = 98.9, less 9.9, leaving 89 units.
Week 44: 89 + 10 = 99, less 9.9, leaving 89.1 units.
Week 45: 89.1 + 10 = 99.1, less 9.9, leaving 89.2 units.
Week 46: 89.2 + 10 = 99.2, less 9.9, leaving 89.3 units.
Week 47: 89.3 + 10 = 99.3, less 9.9, leaving 89.4 units.
Week 48: 89.4 + 10 = 99.4, less 9.9, leaving 89.5 units.
Week 49: 89.5 + 10 = 99.5, less 10, leaving 89.5 units.
Week 50: Equilibrium reached.
Now, run through the numbers based on 35% fresh water each week and see the difference.
