How Pond Dye Can Help With Your Algae Or Weed Problems

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Summer time can be hard on a pond. Of course you’ll commonly see very high temperatures and along with that comes a lot of sunny days.

I’m normally partial to a little sunshine and like John Denver, I like it on my shoulder now and then.

But it can beat down on a pond and stimulate a lot of unwanted algae growth.

In fact, apart from high nutrients in the water, which is the leading cause of algae blooms, all day sun exposure is a huge catalyst for algae of all kinds, and for weed growth in shallow waters.

In the past, we’ve talked about shade as a viable tool to help with algae problems on a small pond. For really little water features, some people have actually used umbrellas, or shade sails with good effect, and had their green water issues clear up quickly.

But if a pond has any size at all to it, providing shade isn’t all that easy to do.

That’s where pond dye comes into play and it can help quite a bit when it comes to sun exposure.

Since the question comes up now and again, it’s important to note that these dyes are non-toxic formulas and are designed to go in the water.

Most are concentrated so a little can go a long way, and you don’t want to get the stuff on your hands or clothes. It won’t come off easily but you could always go as a Smurf to the upcoming Halloween party if you wanted to make the most of it.

The purpose of the dye is pretty straightforward. You want to block or inhibit sun light from reaching too deep within the pond since this can stimulate plant growth under the water.

When using the dye, the goal is not to create a solid mass of color that you can’t see through. A few golf superintendents that we know have done this to combat weed growth and it does work, but makes for a pretty funky looking pond.

Correct use, would be to add enough dye to a pond to start to tint the water. You can still see through it, but with the right amount of tinting you’ll start to refract and diminish the light’s penetration into the water.

I usually advise looking over the dosing instructions and starting a bit below the recommended amount and then working up to a level of tint that you actually like to look at. When done correctly some of these dyes will look very natural and be pretty hard to spot for the untrained eye.

Pond Dye Options

In recent years, new formulas of dye have been developed that expand the color options beyond just the typical blue color. Both black and black/blue combinations are now common for both small and large ponds and I find these two colors to be a bit more natural looking in the water.

Currently the formulas are made of either concentrated liquids (for large ponds, 1 quart of dye will treat a 1 acre pond up to 4 feet deep) as well as what some people find to be a more convenient blend in powdered form. The dye powder is encased in small, water soluble bags that can simply be tossed in the pond and as the packet dissolves the dye get’s released pretty quickly.

With a bit of aeration running to help with circulation, you’ll normally find that an entire pond, even large ones, can be fully affected within 24 hours or less.

I normally expect the dyes to last for up to 5 or 6 weeks in ideal cases. In some ponds they may last longer and in other ponds it will be less. A lot has to do with the turnover rate of the water in the pond, how much rain you might be seeing in your area and so forth. Generally if you can get a month or more out of each treatment, that’s pretty good and it makes pond dye a viable tool for pond management.

Finally, it should be noted that I don’t view pond dye as an all-encompassing tool for things like algae reduction. Often it will help some but it’s not enough to turn the tables and clear the pond up completely. This is why we usually will use it on conjunction with things like beneficial bacteria or specific weed treatments, which may help more directly.

The dye however is supportive of these applications and will help as you “stack the deck” against unwanted plant growth.


Be sure to check out our New Powdered Dye Packets that make working with pond dye, clean and easy!

If you have any specific questions about pond dye that we can help with be sure to leave those in the comment section below and we’ll try to provide a few answers.

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