1. Appropriate filter size for your koi pond size and koi load
2. Feeding rate of recurrence
3. Shaded verses sunlit
4. Weather/environment
5. Waste and debris accumulation (for instance, leaves)
6. Area available for filter placement
7. Pre-filter
8. UV - ultraviolet
9. Skimmer
10. Jets
11. Deepness of koi pond
12. Your financial plan
13. Material accessible
14. Homemade verses commercial
15. Cleaning, occurrence and simplicity
