I am from Cape Town, close to Cape Gate, Koi keeping is a passion of mine and also the science of water, I work for a company called Organic Water Solutions, where we treat water on a large scale, rivers, dams, effluent plants etc. completely organically. So I have a great understanding of bacteria and enzymes and water quality. Our sister company Organic Aqua is used in koi ponds globally to improve water quality.
I hope my suggestions help:
All year round - the enriched nucleotide enhances Koi immunity and you want this especially in winter to improve Water Quality due to bio filter being at its lowest Performance point - bacteria and cold = almost dormant bacteria so you donít want allot of waste. Also reduce water contamination and the balanced nutrition spurs growth.
In summer - because winter is the koi's resting period so you donít want to spur too much growth in winter, in summer youíll see better growth if they rested properly,
Youíll also see in the cold they move slower, you donít want high nutrition food going into the Pond because the fish donít use the energy and it just ends up in your less Effective bio filter due to the cold, summer this food is great for growth, it improves digestion to optimize nutrient intake. It also has a high palatability so the Koi will eat more, be careful not to overfeed with this one, rather more often and only a little, only what all koi will eat in 5 minutes.
I would mix a little wheat germ all year round, more in winter as it has allot of anti-oxidants to improve the koiís immune system and vibrancy in winter. Remember this product also has Astaxathin so rather use less when you mix it with colour enhancer as it contains a higher level of Astaxathin. Astaxathin is ten times stronger than Beta-Carotene and up to 500 times stronger than vitamin E as an antioxidant.
It has been said that when you use products for your koi with Astaxathin to improve colour rather use it less often because people have found that koi lose a little Colour if you over use it especially in small fry. Thatís why I only mix a little wheat germ and colour enhancer in summer and a little wheat germ in winter. But just before a koi show I would definitely move towards more colour enhancer if not only colour enhancer.
As I said colour enhancer I would use just before a koi show and a little bit in-between in summer, winters I rest my koi and feed minimal.
I do stock a premium product that is pre mixed with all the types in one tub that you can use in summer months, this is one of my most popular product in summer.
Winters stick with your, wheat germ and staple
To answer your question in short
Winter: Staple with less wheat germ - 70%-30% (I would cut out wheat germ every 2nd week)
Summer: Growth with less wheat germ - 70%-30% and you can mix colour enhancer here every 3rd week
2 months before a koi show: either only Colour enhancer or 80%colour enhancer and 20% growth
Or if you just want a stable growth, health and vibrancy + water clarity go for the premium in summer.
Winter stick with staple and some wheat germ
I posted this in as much detail as I can right now, but if you read online more about what I said above and look into the ingredients of the product, it would make sense to you. For instance why growth is not a good idea in winter due to food waste and also koi resting time. Etc.
Hope this helps.