Well I hope they do come back and read this, the post are only meant to help. Please do not feel offended at all by the other post. We all are learning everyday. The post are to help so you do not make a mistake that could end deadly for the fish which in turn will not make you feel very good. I commend you in taking on such a task as 40 Koi. If you do read this please expand on your setup at as to what type of filtration etc you have. This may allow us to help further with your setup. Just remember just because someone tells you what you want to here my not always be the right answer. I for one hope you and your husband come back often and share your endeavor. BTW I would love to see pictures of your pond, I really enjoy seeing other peoples ponds. Stick around and you will see there is a very nice group here. For some reason you do not come back, I wish you the best of luck with the Koi.