Crystal BlueBlack Out Lake and Pond Dye - One Gallon of Professional Lake & Pond Dye – Treats Up to 1 Acre – Deep Black Color - Safe for Fish, Wildlife, Pets & Children

This dye works well to keep algae growth low in my pond.

This is my first time using a black dye. So far, I like it. I've mostly used blues dyes, but the end result is usually an emerald green water color with those. It was still beautiful, but not natural looking. The black dye darkens the water to give it a more natural, reflective look (see pic). I used one gallon for approximately a 1-acre pond about 4-5' deep.I can't comment on its longevity yet, but keep in mind that there are many variables that play into that: how much rain you receive, how much water is moving through a spring-fed pond, its size/depth, how much product you use, etc.

I used this product in the spring of 2024 and it worked very well. I did the exact same ting to the same pond in the spring of 2025 and it did absolutely nothing! I don't know what they changed, but that last pack was useless!

Color lasts about a month depending upon rainfall... Seems to settle out over time but the product is cheap enough to toss one in ever six weeks or so.

If you like the green or blue pond dye don’t buy this product. This dye gives your pond a more realistic color and we really like that!

First bottle wasn’t dark enough so they sent me a replacement. They understand my feelings.

Product worked quick in dispersing in pond, lasted about six weeks have ordered more

Terrible job of packaging. Box had no padding, several orders just thrown in together. Box was torn open from mishandling. Not sure I got everything. I think the final parcel was put together by fulfillment center not vendor. Product is an excellent product, good coverage.