Questions About Algaecides vs Nualgi vs Other Solutions

[Bromeliad]

Hi Everyone,

About two and a half years ago, we created a 300-gallon buried stock tank pond with a raised bog filter in our backyard. No fish, just lots of plants, including pickerel weed, arrowhead, rushes, cardinal flower, society garlic, a water lily, and more. On the whole, everything has been going great: the pond thrives in late spring through summer and draws lots of birds and insects and even mischievous raccoons. It's been a real joy, even with a few maintenance challenges.

This winter is really dragging and all the plants in our region are taking longer than usual to wake up and get going. We've always had a little bit of algae in the pond here and there, especially in the colder months, but this year it's much thicker and more abundant than ever before. I think it's primarily due to the slow growth of the pond plants combined with the fact that I repotted many of the plants in the fall; even though I used soil designed for pond plants, it probably still added a lot of nutrients to the water. I don't think it's 'green water'; the water has not developed a green hue. It's mostly clumps of stringy green algae that grow from and cling to the pots and rise to the surface, forming mats. I've been manually removing as much algae as I can, but at this point I am concerned that it will inhibit the growth of the pond plants by blocking light and prevent them from getting a good enough growth spurt to compete with the algae.

What would you recommend? We have never added chemicals of any kind to our pond and I only want to do that as a last resort. Based on some research, it seems that there are a few algaecides that are genuinely safe for plants, wildlife, and pets (such as GreenClean), which would be essential for us, as in addition to all the wonderful critters around here, we have a dog that loves to drink from the pond. I've also seen Nualgi recommended in this forum as an alternative to algaecides.

Has anyone had good experiences with algaecides that are safe for plants, pets, and wildlife, and do you recommend any specific brands? Is the consensus, if there is one, that Nualgi is the only acceptable treatment? Or are there other solutions we could try?

Thanks as always for your help and expertise.

 

[Mgessert]

Last year I had a similar problem and added some potted plants while I waited for my others to wake up. The water cleared up by mid May.

 

[Hound Heaven]

Spring hasn't arrived here either and the string algae keeps trying to take over. I don't like using chemical additives so I started using hydrogen peroxide with pretty good success. I turn the pump off and lower the water level in the bog where the algae is the worst, and squirt a bottle around onto the worst spots. I give it a few minutes to start bubbling and then plug the pump back in and it will circulate through the waterfall and the pond.
It may not make it all disappear, but it sure slows it down. Then I scoop it out for the garden plants.
Good luck.

 

[Lisak1]

Green Clean is just sodium percarbonate packaged up and sold for big bucks. Save yourself some $$$ and just buy the compound. Sold for soap making. (Edited to add: sodium percarbonate breaks down into hydrogen peroxide and soda ash. It's just a powder instead of a liquid so I like using it on rocks and areas where it can stick to the algae.)

Algaecides - used properly - won't hurt plant life. It's the fish they're deadly for - I wouldn't even worry all that much about a dog drinking it to be honest, unless it's a teeny tiny dog.

HOWEVER - you may want to dig even deeper and figure out what's in the water that's feeding the algae. My guess is rotting organic matter. You can reduce the algae's food source by getting rid of anything from the water that may be giving it nutrients.

 

[Bromeliad]

Thanks so much, everyone! Much appreciated. I'm going to keep trying mechanical removal for now, and possibly consider some hydrogen peroxide or sodium percarbonate depending on how things evolve.