I just found and read your post about your pond. A couple of more thoughts:
Please consider creating a QT in your basement -- at least 150 gallons. Keep 2 known-healthy comets in there to keep the filter cycled. All new fish must spend a month in QT. If you are not up to scraping and scoping, do a shotgun treatment on everybody in the QT. (My canary comets are probably brain damaged from all the parasite treatments they get, poor dears.) Don't add new fish to QT during this time. The QT will also be invaluable when you need to bring in a sick fish for treatment. Last November a 14" koi ripped a dragon scale. Without a warm QT in which to spend the winter, this cold blooded creature would not have been able to heal, died and contaminated the water for the others.
Keep your stocking rate lower than you may like. 3000 gallons: 18 comets OR 6 koi total max (substitute 3 comets for 1 koi) but be prepared to do ruthless comet fry culling next year. (Walmart minnow trap.) I know your fish are small now but they will grow fast, make lots of poo which you will have to spend much time cleaning up, you'll get tired of all this maintenance, slack off, they'll get sick, start dying, you'll get frustrated, give up and all that money and effort is down drain. Then every time after that whenever you and your husband have a disagreement THAT POND OF YOURS will work its way into the conversation. A properly stocked pond is so much less expensive than a divorce attorney.