Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Elodea overgrowth in trout pond

I hope to get some advice about what to do about the massive overgrowth of Elodea in my 1/3 acre, 10ft deep trout pond I have in the mountains of Colorado. Now that run off has stopped, the water level is dropping and the elodea is taking over, so my fish seem to be podded up in the 2 areas of the pond that are not full of this plant. I aerate it 24/7 at the deepest part, and now we are having our highest temps of the year.
Here are my questions: 1)if I rake it out in the deepest places to give the fish more room, will the water heat up more since there will be less shade? 2) what chemicals can I use to kill the elodea (and I'm sure of it's ID) that won't harm the trout?

No expert on this subject but .. if it's as bad as you say then the only option for now is to manually remove it from the pond. Killing it in place will surly endanger your trout via crashing DO.
Maybe next year it could be treated just as it's getting started.

JHAP has some extensive elodea experience. Hopefully he can share his knowledge, perhaps once back in Sandy Eggo with more time and bandwidth.

Ric and Theo offer sound advice.With only 10 ft of depth I would move the diffuser to higher ground and perhaps run at night only. Highly suggest monitoring your water temps at 50% of depth.Research labels for your State and County and see if Sonar PR is an option. It will set the Elodea back slowly for this season. Next year apply it early in the season. Also consider treating 10% strips at a time with Diquat and a vegetable based surfactant with Sonar.Every 5-10 days do another 10% Mechanical removel in the deep spots wont warm your water a lot as most of the temp increase is probably coming from your aeration. Stay away from even the low rates of chelated coppers as warm temps copper and trout dont mix even at very low rates.Depending on your diffuser type and compressor you may be able to slow the system down also by bleeding of some of the exhaust.If moving the diffuser is not practical you may also be able to add risers to the discs,stones,tubes or whatever you are using and leave the weight base in the same location.

My pond is teardrop shaped with the deepest part in the center of the widest part of the drop. I think I could remove small areas of elodea with chemicals and not affect the DO, if I raked out the dead/dying plants too. I'll look at the products you suggested Ted. My problem in the spring is that the pond overflows with runoff, and drains down into a local stream, so I don't want to put a chemical in that could affect downstream water. So I've wanted to wait until it quits spilling over to treat with chemicals and then the elodea has already taken off. Any suggestions on what I could use early on that would not be a problem for this situation?
My aerator is a flat square pan type filled with sand that sits on the bottom so I can't really raise it but I have not been turning it off during the day. Night temps have been 48-58 degrees and daytime highs have been 85-88 this past week. I've wondered about the effect of the temp in the air that I'm running to the diffuser since I have a 2000 ft run in black polypipe that goes over lots of bare sunexposed ground... I'll try turning it off once air temps get above ?70 in the morning and back on once they drop in the evening and I'll monitor the pond temp, fish activity.
Thanks everyone for the advice, I love having access to this great resource!

Also, does anyone know if I can compost all this elodea that I'm raking out of my pond? Or use if for mulch?
DocBarb Sutton

I wouold treat in sectiosn with Reward, fairly easy to kill wait two weeks and see results before proceeding to next section. One gallon will be more than you need for 1/3 acre pond.

Thanks Greg, I'll look at that. DocBarb

I second what Greg said about Reward. I used a Reward/Cutrine mix to treat Elodea and it worked wonders. Not to contradict anything that Tea Lea says (he's an expert and I'm an amateur) but I would ONLY mechanically remove elodea that has been treated and is dead. One of the ways Elodea spreads is through plant fragments. I made the complete idiotic mistake of trying to manually remove live Elodea and the end result was that it spread all over the pond! I'd recommend that you treat a small section of the pond with Reward. My experience has been that with a Reward application you will see the plant dying back within a couple of days - it will turn brown and the leaves will shrivel. IMHO, I would wait for a couple of weeks to make sure that the plant is completely dead before you manually remove it. Reward will do the job, I can attest to that.

Jeff your very correct on the fragments spreading. In a small pond situation I prefer adding Sonar PR with the diquat,copper mix to ensure a total kill.Ive wittnesed incomplete coverage with diquat/copper just to see the problem reoccur as bad if not worse. The PR will last the rest of the year and in a small pond can be good insurance.

Thanks, I think I will start with the Reward in the one area of the pond that is shallow and totally blocked in by the Elodea. I already have the plants completely overwhelming the pond, so I'm not worried about spreading it by manual removal! But I am worried about crashing DO levels and keeping my trout from dying - I've got some 5+lb fish in there!
I've been removing the Elodea that's at the top, and I'm wondering if I treat the now open water areas with the blue dye, will that allow enough Oxygen production but slow the regrowth of the plants that remain under the surface? Any thoughts on that? DocBarb

Docbarb, yoru concenr abotu Do crash is godo one that is why you only treat small amount at a time. Also keep in mind if it was not clear do not use copper products the trout are very senstivie to heavy metals. I do not recommend dye while using the herbicide you want as much photosynthesis as you can get to add DO during the eldoea dieoff.

Just keep in mind what the experts (Greg and Ted) have mentioned. Only treat a small portion of the pond at one time. If you kill a massive amount of the plants at once you could cause an oxygen crash. Treat in small sections and be patient, that's much better that losing your prized fish.

Often the label suggestion of treating only 25-33%can be too way much at one time. Diquat will react fast with proper coverage especially if you apply when sunny (do apply with sun in the forecast if possible) and takes Gregs warning on no dye at this time as you will need all the DO you can get if it turns to clouds for several days.Have two fish kills going on now with Crystal Plex and Diquat with lots of aeration because the 1/3 teatment on FA was too much (pond owner applied)D.O. in yesterdays clouds was 2.37 ppm and today 6.65 with lots of sun.USE CAUTION !! and good luck

Thank you for the great advice, everyone. I'm going to start at the small end of the teardrop part of my pond, which is a solid mass of elodea and work towards the deep end, slowly, and remove dying weeds as I go. I don't think I'll be able to completely remove all the plants, but at least this will give me a way to control it.
Will I be able to safely eat my fish?

DocBarb

Here's a table on water use restrictions from Keystone Hatcheries (a Pond Boss vendor), according to this table there is no restriction on eating fish when using Reward/Cutrine mix. Which corresponds to everything else I've read about Reward/Cutrine. I don't have any knowledge or experience with any other chemical.

Keystone Hatcheries web page

You should be able to safely eat your fish. Well as long as you don't poke your eye out with your fork while playing "airplane."

Thanks, Jeff. I'll let you know how it all goes. DocBarb

Please do keep us updated Doc, that's how we all learn.

I raked and hand carried it out and to my surprise the deer ate every single strand of it. Gone.

Very good information - Elodea makes good deer food.