Pond Boss Forums POND CONSTRUCTION Renovating a Pond or Lake? Semi Trash Pump

I am looking at a semi trash pump to remove some floating weeds like duckweed and algae. Also I want to use it to remove muck.
My question is 2"or 3" I plan on using a dewatering bag or two to have the water flow back into the pond.
Probably a HF model.

If you plan on pumping very much pond bottom muck I think the standard trash pump would be a better choice as it is a little more expensive and would cause fewer pumping problems with heavier coarser sludge type of materials. As I know it a semi-trash pump is more of a clear-muddy water pump. The pond bottom could easily have some sticks, heavy leaves, and small stones in the muck. Additionally IMO and experience the 3" model will be well worth the extra money for bottom muck.

Ditto what Bill said. Run the numbers re: gallons per hour moved vs gallons of water that's in the pond. Just so you don't suck the pond down too far.

That is one of the reasons I was going to use a 2". I don't expect to this in one session but over time.

Whatever hose size or semi/full pump you decide on, babysit that pump when the muck gets milk shake thick. The thickness and weight can keep the pump from lifting, and it just churns the muck. If the pump housing is aluminum, it looks at muck like sandpaper. Yes, I've been there with a track hoe operator sitting in the cab watching it.

Afterthought: If you buy the Harbor Freight pump, make sure a replacement pump housing is available. Northern Tools do offer them on their pumps, but they're not HF cheap...

It is a small pond maybe 1/2 acre. I will be doing it in stages with some raking in between. Just as you said I do not want to pull out too much water at on time. The pond is only fed with run off and drain from the roof of the house.
That and I read where the 2" was used by well people for sucking out mud.

I'm currently using the Harbor Freight 2" semi-trash pump to empty my pond for de-mucking and repair from muskrats and crayfish damage. I debated between the 3" and 2" also, and decided that while it will take longer to drain, they both accomplish the same goal. Plus hoses are less expensive and cumbersome to put in position. Also carrying a 2" pump vs a 3" pump to my drain site is less strain on my back. So far, I've been very pleased with how it performs. I was worried because there is quite a lot bottom growth (I can't think of the name but I think it's string or vine algae or something like that), and I was afraid it would suck up this stuff and clog up either the strainer or pump itself. So to keep that from happening, I fastened the strainer (with hose attached) to a flexible (or rubberized) tray I found at Tractor Supply. It's around 2' long x 16 inches wide x 6 inches deep. I drilled a lot of holes to allow water in and to let water out when removing from pond. I used zip ties to secure strainer and hose to the tray. I also tied poly rope to tray so that I could go on other side of pond and pull strainer and hose into position in pond. The tray has performed exactly as I'd hoped. I'm new to PondBoss and I would attach a photo but I can't figure out how.

Now, if time is a concern, a 3" pump will move that water out much faster. If you have a large pond, that is the best way to go. My pond is just under 1/2 acre and the 2" pump works fine for me. I will say that if you live a considerable distance from your pond site (like I do) and have to drive to it each day, a 3" pump will result in less time baby sitting of pump and fuel level.

I put the suction hose over and through a car or truck inner tube to keep it off of the bottom. Screen and all.

The inner tube method sounds pretty good too. I'm not sure I fully understand, but as yours nears the bottom, doesn't it begin to suck up debris or does the strainer keep it out? I have a semi-trash pump and I worry that it will choke the pump without using a tray under it.

I just wire the inlet end of my suction hose to a 1-gallon bleach jug. Very light and easy to carry to the location. If I actually start drawing down the water source too much, I just shorten the wire a bit to keep the strainer still off of the bottom.

The white jug also makes it very easy to see where the end of your hose is located if your a pumping from low visibility water.

Thanks!

The reason for the tube was sandy soil and having to move the inlet frequently due to water level dropping. I tore an inlet hose picking it up with the excavator, it was full of sand and pulled apart. I couldn't move it otherwise it was so heavy. That's when I thought about the tube. A bleach bottle should work too. I used rope on the tube to keep it from floating to shore and to keep it in deeper water.