This summer has so far proven to be high on the pollen scale. The fluffy and fine stuff is floating everywhere. Did you know that the pollen is effecting your pond? Just like the pollen lands on your furniture indoors and coats your porch it also lands in your pond. The pollen isn't harmful to your water but can change the color. Often, this time of the year we receive many phone calls about sudden yellow water. The clients concern often is that this is caused by algal blooms or some sort of unbalanced water chemical.
Worry not, it is only pollen. Some pond owners will have the system pumped out and refilled at the end of the pollen season. This is acceptable. However, it should be noted that the beneficial bacteria can take up to 3 weeks to form a healthy colony and by emptying it you are essentially restarting that process. Otherwise, you can leave the pollen alone and it will either settle to the bottom to help your beneficial bacteria or be pulled into the skimmer net and emptied a few times a week. It's all a part of Northern Michigan nature, just like your ecosystem pond.
Another cause of yellowed water is deer spray that enters the water. The deer population in Northern Michigan makes all gardens susceptible to grazing. When spraying your garden with the liquid form of deer repellent please be careful to keep it out of the pond. These products are often high in ammonia and can alter the pond ecology quickly. Occasionally (but rarely), this can also lead to fish death. We recommend that around your pond you switch to a powdered product called Deer Scram. This powder not only works but will have minimal impact on water quality (additionally it smells of cloves for a day or two and then nothing- no more deer repellent that keeps you out of the flowers too!) We still recommend you do your best to keep it out of the pond but the powder is much easier to control than the fine mist of the liquid versions.