# best way to clean a pond



## Skimboarder_07 (Mar 3, 2005)

I have pond in my backyard about 11 feet by 13 feet and 32 inches deep. Theres about 35 fish (gold fish and koi all under 5 or 6 inches), theres some lilly pads. The pond has been up for about three years now and weve added water and regularily clean the filter but the water is still a pea soup green and were theinking that a major water change is in order. Our plan is to take all the fish out and place them in garbage cans full of water (obviously clean garbage cans with plastic bags in so the plastic wont come in contact with fish) we then plan to drain the pond to about knee or shin level. We plan to wash the sides of the pond(removing algae growth) and more importantly cleaning most of the sludge up off the bottom and then refilling it and proably readdign the fish that day....MY question is am i missing anything or should i be doing anything different


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## Toby_H (Apr 15, 2005)

Is this a man made pond with a plastic liner? I would assume so but better to ask than assume...

Is there 'substrate' on top of the liner?

Does this pond have any filtration on it? Does it have any vegitation in it (if so please describe)?

Are you going to be able to siphon out the water or do you have to use a pump to remove it? If you are able to siphon I highly suggest swirling as much waste/debris into the water column as possible to be removed with the water change. This will greatly reduce the amount of labor you have to do to remove it.

I wouldn't worry about the plastic bag in the tub. Typical Rubbermaid trashcans are safe to put fish in. Just be sure that the label doesn't mention anything about fungicide, mold inhibitors, odor killers, etc...

I wouldn't at all discourage a thorough cleaning and huge water change... but I also do not think this will solve your problem. Fish waste will continue to add up and the natural sunlight will still feed algae growth... unless/until you have something in place to prevent it...

Simply dropping a couple of pumps in the water to create movement will help alot. This will move the waste around and cause it to break down much faster... Adding plants will assist the waste in breaking down faster as well as eat the pollutants the waste breaks down into... Adding a UV light will make a world of difference regarding water clarity / preventing green water... Using a pond filter (huge canister) is also another good option to assit in water clarity...

If you have a bare bones pond to start with... and are looking to upgrade... (IMO) I would consider adding items in the order they are listed above.

If you choose to add a pump, I highly suggest adding one with a healthy prefilter. Debris getting in the impellor will greatly reduce the life of any pump. Mag Drive has a very solid reputation with their larger pumps and I've had very good experiences with SEN pumps.

Pond plants are regional, so I'll leave that research to you to do...

I have a BioForce 2000 pond filter that has served me well for over 5 years. I've run it with both a 1200 gph pump and an 1800 gph pump (tried 2400 but it was too much). They also make these units with a UV light which will be enough to help with green water, but I like to run my water through UV lights much slower than this would offer to increase the benefits of the UV. I am very pleased with the BioForce filter. I should also mention I've seen a 'pond filter' on Ebay that is a very similar design but has the added benefit of a backwash feature. This allows you to very easily clean the filter out as well as drain water from the pond (i.e. water change). I have never owned/used one of these filters so I cannot vouche for the quality of craftsmanship, but the backwash feature made itvery interesting to me.

As for UV lights... if you do not get the ones built into the Pond Filter, I highly suggest checking out the Danner UV lights. They come in 10, 20 & 40 W sizes. They are tough as nails (very dense plastic housing), are 100% submersible, have very visable glowing rings (so you know when the light is on), quality quartz sleeves... and I can vouch they work very well and last the tests of time. I put a 40W UV @ 1800 gph & the BF 2000 on a friends 5' x 16' @ 2' deep pond that was solid green (could not even see the outline of white fish 6" below the surface)... in 24 hours you could see the bottom of the pond and in 48 hours the water was very clear... in 72 hours we removed the filter when the water was literally crystal clear (that was with zero water change).

Cluing us in on a few more details such as the questions above will allow for more pointers in the cleaning process... Any other details you can think to share will only help us give you better "custom" advice...


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## Skimboarder_07 (Mar 3, 2005)

sorry kind of forgot to mention some of those essentials the pond has a pump init it pumps 5000 gallons an hour there is a water fall element that adds water current and there is a large filter 3x16inchesx16inches, as well as a UV light suggested for ponds in between 2000-4000 gallons, there is also marginal plant cover as i have 7 ornamental lilys and 3 large native lily pads in the pond, these dotn cover a large amont of the pond (1/4 at full bloom and right now there just starting to come up) as well there is a net that covers the pond that keeps there heron at bay as well as keeps most leaf litter out, I know that if I want the water to be crystal clear I need to cover 80% of the surface but then i might as well just have a floating lawn.


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## Toby_H (Apr 15, 2005)

Wow... so you have just about every suggestion I had for you covered... :thumb:

When was the last time you changed the bulb in your UV light? They will continue to illuminate long after the UV qualities of the lamp are burnt up...

Again, I would by no means discourage a thorough "spring cleaning"... but with that much water movement and a UV light I'm suprised to hear you have that much "green water".


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## toddnbecka (Oct 23, 2004)

I have a no-tech pond in my backyard. It holds water lilies, rosy reds to eat mosquito larvae, and a recent crop of toad tadpoles. Every spring the water is pea green, but clears up a little later in the season.


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## zugbug (Dec 12, 2005)

add bundles of barley straw and water hyacinths for algae control. I've used both and they work great. For some reason the algae attaches to the roots of the water hyacinths and I have no idea how the barley straw works but it does.


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## dolphinlover (Apr 3, 2008)

I hate to see someone "clean" a pond of that size, man that is a whole lot of work, and I hate to say this, but you will probably do all that work, fill the pond, put your fish back in, and then in a week or so, it will turn pea green again, you will force your pond to go into another "new" cycle by changing all the water.
I have a 18' by 18' by 3' deep pond, and I have NEVER cleaned it, I have 33 Koi and most are over 2' long, and have several that are over 3' long.
The green algae that is on the sides of your pond is a good thing, it is a natural food for the koi.
I also don't have plants in my pond as my Koi are so large that they wreck any plants we attempt to put into it.
I believe that the problem is that your UV light is not large enough, I tried several smaller UV lights hoping to save some money, but in the end the only one that has kept my pond "green free" is a 120W light, it is spendy but it is so worth it to see our fish all year long.
And it is a MUST that you replace the UV lamps every year, which is also spendy but like I said it is a must.
Also your pump is too large for your filter, your pump is pumping 5000 gallons an hour, but your filter is WAY to small to handle that flow rate. You need a much larger filter or maybe 2 larger filters, we use home made filters made out of 55 gallon plastic barrels, with bio rings in the bottom and filter fiber in the top.
I hope these suggestions help you, I know how frustrating it can be to have your pond pea green all summer.


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## Skimboarder_07 (Mar 3, 2005)

just curious how do you know my pump is too big for my filter??/ i didnt even say what type of filter i had I just said a double box.....plus that pump powers two water falls too and only half the initial flow goes ot the filter


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## dolphinlover (Apr 3, 2008)

Well you said that your filter was 3x16"x16", that is not a very big filter, and you said that your pump puts out 5,000 gallons an hour, now with even 1/2 the flow going to the filter, it's still too small imo. The faster you have water flowing through a filter the less effective it becomes.
As an example, I have 2 1,200 gallon pumps that each flow through 2 55 gallon barrels, the flow is slow and steady, not only does it clean the pond very well it creates a great bio filter in the process.
I have a additional 1,200 gallon pump that is split between the waterfall and our UV light, the UV light is the same way, the slower you run water through it the more effective it is.
Don't get upset, I'm just telling you from YEARS 16+ of experience what we have found, and I'm just trying to save you a whole lot of work.


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## Skimboarder_07 (Mar 3, 2005)

i wasnt getting upset i was jsut kind of stating what i thought, the flow through my filter may be a little different then your i think in mine the water comes into the bottom going through sponges but then its outflow is through the top of the box where it passes through more sponges and tiny slits in a plastic barrier, i think you may be right about the UV light regardless i still emptied the pond and repotted the lillys so inthe end still worth it imo


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