Mosquitos in Bog

[andyk]

I installed a bog filter this year and am noticing a lot of mosquitoes coming from it. Unlike the pond, there are no fish to eat the larvae. Pictures of the pond are here: https://www.gardenpondforum.com/threads/andys-pond.26856/

I have a couple of questions:
1. Should there be standing water in the bog, or should the goal be to get water entirely below gravel?
2. If there should be water in the bog, are there any ways to minimize mosquitoes?
3. I've gone three years now (1 with bog) using no chemicals in my pond. Is this my breaking point where I need a chemical additive to kill mosquitoes?

There is moderate water flow in the bog - as in, it is not stagnant and flows well - but the mosquito larvae find ways to hang on to the sides, or behind plant stems and leaves. Water level is anywhere from 1/2 inch to 1 1/2 inch over the gravel / crown of my plants.

P.S. I moved a bunch of this years' tadpoles (maybe 75-100?) to the bog. An absolute feast for them up there vs. the main pond which their brothers and sisters have cleaned pretty well.

 

[addy1]

I have never seen biters in my bog, there are some areas that don't have constant flow but most flows well.

 

[IPA]

Your bog should flow evenly as much as possible front to back. If you have corners or pockets were there is too little flow just add gravel in those areas. Initially most of my bog gravel was under water and had some deep spots but I have found that only about 1/2 inch, opposed to 2 inches, was more ideal. Part of my bog has gravel above or just to the water level and about 1/2 before the fall is below the water; it’s used daily as a bird bath. Is it possible you need a larger pump? Not enough holes/cuts in manifold? Either the head pressure, pressure from flowing through gravel dramatically reducing rate? Cheap generic pump failing or not meeting specifications? Clogged lines, Impeller, Intake?

Edit: Add, there is no way a tadpole would not be washed down into my pond. I’m probably turning the pond water over less than 1.5 per hour guessing restriction in flow, everything is washed down to the pond.

 

[andyk]

I have a variable speed pump that works really well. I can turn it up farther, so much in fact, that my bog could overflow its containment. Maybe I should take a video. The water moves pretty well but the mosquito larvae seem to be able to stick to the sides of rocks, stems and the liner itself anyway. I think some of my tadpoles have gotten washed over the waterfall back into the pond but some are still hanging on.

By the water flows well, I mean that if you were to put something in that floats, it would travel the length of the bog (5ft) and over the falls in a few seconds.

I was wondering if maybe I should increase the gravel level so there is no standing water, or dramatically reduce it to help reduce any tiny spots of slow moving water or reduce areas where the larvae can stick to.

 

[IPA]

I would at least along the edges. If it flows that well then you can still leave some of the gravel below the water where eddies won’t develop slowing water flow.

 

[addy1]

I would walk the bog, or stand outside and stare at the flow. See where the slow/stopped flow is, move the gravel around so it is not that way. I had to adjust mine, not due to biters, but to make the flow I wanted. Like said above any spots the biters seem to like, add gravel get the gravel above the water line.

 

[Lisak1]

We have also never had a single mosquito larva in the bog so that is curious. We have so many frogs in our bog that we barely even see a mosquito around the pond. In the rest of the yard - yes. Tons. But never in or near the bog/pond.

Pictures might be helpful!

 

[addy1]

Since we built the ponds we have had no biters in our yard. One street over they complain about the bitters. To many birds, dragon flies, frogs, toads etc that eat them up.

 

[Mmathis]

@andyk I went back and looked at your pictures, but I’m not seeing the bog. There are a lot of plantings around the pond, but they all look like they are in soil, not gravel. I’m obviously missing something.

 

[Tula]

Following with interest. I have areas in the bog where water isn't moving, so I'll add some gravel. Haven't noticed any mosquito larvae.

 

[addy1]

Following with interest. I have areas in the bog where water isn't moving, so I'll add some gravel. Haven't noticed any mosquito larvae.

I end up with tadpoles in the bog I think they help if one does lay there, but I have never seen a biter larvae in the bog

 

[Tula]

I end up with tadpoles in the bog I think they help if one does lay there, but I have never seen a biter larvae in the bog

I too had some tadpoles, but think they were washed into the pond.