Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants better to remove algae or kill chemically

I live on a communally owned and used pond/lake. We are having an algae problem. We are addressing the source of the problem and working towards a long term solution but need to deal with the bloom now. Some have suggested using chemical to kill the algae which is a good, quick fix. My question is; would it be better to physically remove the algae instead? My thinking is that if the algae dies and sinks, it is simply feeding the next bloom. Removing the algae from the water physically removes the nutrients trapped in that plant and takes it out of the ecosystem.

Comments and advise are more than welcome.

How big is the BOW? Also, are there fish in the water?

Killing alot of algae with chemicals may remove too much dissolved oxygen unless done systematically (1/2 or 1/4 at a time). It also may leave excess nutrients in the water.

Removing the algae manually is a quick, inexpensive fix if you make it a community effort.

It is a 17 acre lake and the BOW rings the shore to about 10 or 15 feet into the middle. Good point on the killing method. We are planning to do 1/4 or less at a time. We have talked to our local DNR and they said never go above 1/4, and after the water temp exceeds 65 degrees it is even more dangerous. We are in the upper 60's now.

Have you considered putting tilapia in? I don't know the Iowa laws on them, but if legal it might be worth trying if you have a source for the more cold-tolerant Blue Tilapia.

That's a seriously nutrient rich lake. You might want to also talk to the property owners about reducing their use of lawn fertilizers as well. Aeration could help some too. Even killing off just a quarter of the stuff would have me worried about an O2 crash. Yikes. I would try to manually remove as much of it as possible first.

We have some grass carp but I know they aren't Tilapia. What do they do different? We are trying to get ground support to end all fertilizer use in the neighborhood. Some people are addicted to the stuff though so it may be an issue for them.

Mix algae with a bit of manure...good natural fertilizer

Hey Blue Gill World,
Some savvy pond managers use bioaugmentation with their algaecide or herbicide treatment to limit the amount of soluble nutrient from the dying and dead aquatic plant. Complementing the algae treatment in this way has extended algae control and minimized the presence of copper or other algaecides in the water.

That sounds interesting. What can be used for bioaugmentation? We have swimmers and fishermen so I need something safe for both.

Grass carp are not your choice for filamentous algae. They are only effective on rooted plants and have preferences even then, and are not immediately effective.

As long as you have even a few people applying lawn fertilizers you will be dealing with this forever. It doesn't take much.

That's a large body of water for manual removal. Would take the entire community. To me there is a size cutoff on quick fixes or certain treatment. You almost can't tint a lake that big. You are 100% correct that it is better to remove the stuff than load your pond with copper, kill it and feed the next bloom with dead algae. Also the O2 depletion. Where grass carp will not eat it, Common Carp will. We use a lot of hybrids with great success. They don't reproduce very well, if at all, and they just eat that algae up. It is almost first on thier list. Negatives are you are stuck with a ton of carp, which can be turned into a positive with community carp hunts, and fishing tourneys. And they do roil in the mud and make the water turbid/cloudy. Especially where they feed. We have many drinking water lakes, where they are thick, and there is zero algae. I have a big pond that cycles through, the water temps increased, and it is almost gone now. The bigger the body of water, the more expensive and tougher the solution. And the expense skyrockets.

What kind of algae is it?

And of course it's most likely it will come right back which could discourage any future community effort.

Yes, that immediate comeback pops the enthusiasm balloon. Like I always say with algae, it's just a symptom, address the cause for long term success. And if you have that type of acreage and algae is a problem, you have a problem. I just don't see algae in my area really causing issues in large bodies of water.

We have a mix of platonic and filamentous algae.

bluegill world,
The bottom line is, you can throw tons and tons of money at fighting this FA problem, but you'll never get ahead until the massive nutrient load coming from heavy lawn fertilizer applications ends.

It's a bummer, but green lawns = green lakes too.

I agree completely. We finally have the neighborhood on board the no fertilizer wagon and now we are just trying to control the problem on a short term basis.

Sounds good! That's excellent progress. I know it can be extremely difficult dealing with a community owned pond/lake.

Good luck, and make sure to keep us informed on your progress. We're always happy to give input and advice!

I don't know about tanks, but this community lake needs the fertilizer runoff stopped, which is most likely the largest contributing source. That is a huge step in the right direction. Then hopefully you can get natural methods to compete with it. Beneficial bacteria, plankton blooms, shade plants, algae eating critters. Those would all be long term solutions. For this season, you may have to bite the bullet and copper it out with algaecide and manually remove what you can for the quick fix end of it. But again, with a body of water this large, you need a long term plan and treat the source. Residential runoff into a community lake is a tough spot, keep up the good fight.

Hello laradavidson and welcome to Pond Boss. Thanks for joining in and posting.

Keep in mind what is being discussed in this particular thread is a 17 acre lake, so it's not getting moved anytime soon.

Is Hydra International one of our Pond Boss vendors? I don't see them listed in the magazine.

Our boss (Bob Lusk) is fairly protective of our vendors and rightly so. The PB Vendors contribute to the site and the magazine but more importantly are screened by the Pond Boss himself.

If your link is to an approved vendor then I apologize for the comment.

Keep on posting, that's what makes this site work!

Well, we have been treating the algae with Crystal Plex and it has gone pretty good so far. We started with a bay that had a huge amount of growth and monitored the oxygen levels. They really didn't dip that much. Then we looked at the rest of the lake and realized that there was just a thin layer of algae on top of emergent coontail making it appear thicker. We treated the rest of the lake with great results. At day 2, oxygen levels are close to normal and 80% of the algae has been zapped.

One unintended, but beneficial, effect is that we have applied this stuff in just high enough concentrations to zap some of the coontail as well. While we want to leave some of this growth for the fish, we did simply have too much and needed to thin it out. Much of it is slowly dieing and we encouraged the neighborhood to pull out this stuff to help with oxygen depletion. Should be relatively easy since the roots have release and it is just floating on top.

Thank you for all of your help.

Algae is still knocked down to a paper thin layer which is only present in small areas. Now it is on to controlling the coontail.

Nice to see someone do it right and get results for once. Crystal Plex is a 20% Copper Sulfate. Or 5% copper equivalent. That was the way to go. Plus keeping the dosage low, pulling the material to avoid O2 delpetion and monitoring it as well. Great job. You have a future in the pond maintenance business. I might give the pond a little time to see where it is at.

Coontail - Maybe the coontail will die off gradually, a bit late in the season to tackle it with chemicals. What is your estimate of % of coontail infestation now?

I would estimate the coontail at 20-30%. The problem for us is that it is blocking access for many of the residents. Beaches and docks are useless. While I agree that it is on the late side for using chemicals, we have some Hydrothol 191 remaining from this spring and the membership has voted collectively to use it to open access points. I am going to reluctantly apply in strategic areas and promote the harvest of the dead material.

Thank you for the complement. I am actually looking into starting my own business doing this sort of thing. I really like the challenge and there is a shortage of people doing it around Eastern Iowa.