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Duckweed Dave's Guide to Surface Skimmers
Algae & Floating Plant Removal Made Easy
I live in north central Florida, by a shallow retention pond that serves our neighborhood. As the pond is ornamental we work hard to keep it looking good & decided to attempt to run our pond without chemical addition in order to reduce the amount of expensive chemicals added to the environment. Unfortunately with the widespread use of lawn fertilizers in the vicinity & their natural rapid leaching out into the local watercourses, our pond rapidly became covered with a dense covering of weed.Not being an aquatic plant expert, I can't tell you what the plants were - but they were reducing the oxygen content which was beginning to kill fish. Fortunately I had the advice of Rob Rice - President of the Native Fish Conservancy - to help me in my clean-up campaign, & fortified by the knowledge that I had to "get rid of the weed on the surface" I began my task.
Instructions: Now I know that no-one actually reads "Instructions" but there are some nuggets of advice in here - I'll leave it up to you. Leave a few feet of rope at one end as your trawling line & ignoring the yells, screams & pleading, cut your kid's pool noodle into 2" lengths. Thread the noodle slices onto the rope & hold them in place by knotting the rope either side. 
The intent here is to have the noodle slices not directly attached to the rope. If you loop the rope round them, when you pull the rope taught it will cut through the noodle slices. Your pond is now full of duckweed AND bits of brightly colored chopped up pool noodle! (I speak from experience here) Space out the noodle slices at 4 to 6 foot intervals. This will involve some trial & error (& probably some blasphemy too as you try to undo wet knots that you tied too tight in the first place) as the ideal spacing will depend on the depth of your duckweed, the weight of the rope & the thickness of your noodle slices. I found that one noodle gave me more than enough slices to complete a 180' Duckweed Skimmer. Actually you don't need the duct tape, but no self-respecting handyman should ever be without it & anyway you'll need it to repair all the noodle slices you chopped up by not reading the instructions & looping the rope around them! Using the Duckweed Skimmer: 
The key to this skimmer is that you need a rope to float generally a couple of inches under the surface so that it catches the weed around it's midriff & bunches it all up in front of the skimmer as you (& a friend) trawl the skimmer across your pond. If friends seem mysteriously absent when there's 10,000lbs of duckweed to be removed from a pond, don't fret. I found that trees make excellent skimming companions. By tying one end of the skimmer to a tree I could single-handedly skim our pond in a huge arc until I ran out of rope & then tied my end to another friendly tree & scooted over to the other side of the pond to scribe another arc from that side. As with a lot of things, the skimming works best done slowly & smoothly, however if you do get some weed escaping you'll need to pull the rope taught like a tightrope to lift it out of the water & back over the escaping weed. (This is why you don't want to loop the rope round the noodle slices.) Also- a word of advice here: If you're a married man skimming your pond with your wife & you wish to remain married, warn her BEFORE you suddenly pull the rope tight! A surprise inter-spousal tug-o'-war across a weed infested pond is rarely a formula for inter-marital bliss! Using this method I was able avoid divorce proceedings & also to clear the surface of the pond by consolidating the weed into a fairly solid mass at one end. Then I scooped it out with a spring rake & took it away for composting. Our pond is roughly a right angle triangle with sides 180', 220' & whatever the square root is of 1802 plus 2202, & I removed 25 wheelbarrow loads of weed before the pond was clear. After that it was time for another cup of tea... The result of this weed removal was a clean, clear pond in which our previously asthmatic & half blind fish now jump for joy (& flies) as they have regained their breath & can actually see the flies landing on the surface. However another affliction then struck our clean pond & this one was even more hideous & devious than before - Algae. As the Duckweed Skimmer is designed to float just under the surface, it was powerless to prevent the covering of algae so it was back to the garage & another cup of tea, which resulted in ? The Algae Skimmer Parts Required: (Unfortunately this one costs a bit more than the Duckweed skimmer) One length of floating rope. (Preferably longer than? you get the picture) Cheap water ski rope is perfect. Enough lengths of foam water pipe insulation to stretch the length of your skimmer. (The thinnest, cheapest is fine.) Enough lengths of 3" Nylon lawn chair seat webbing to match the length of your skimmer. (I found it on sale in 40' lengths) A big bunch of tie wraps Some weights (I used a combination of some old heavy galvanized washers & some 20' lengths of light duty galvanized chain) 
Some Duct Tape (see above!) Instructions: (Yarda Yarda Yarda!) Thread the rope through the pipe lagging. There's no need for knots here as the lengths of insulation should butt up against each other. (That makes sense to me in English English - I hope it means the same thing in American English & I don't get hauled away by the Cyber-Police!) The insulation will have a pre-cut slit down one side. Slide the webbing up into the slit & secure it in place with the tie wraps. Don't pull them too tight, as you still need the rope to be able to move freely through the center. Using tie wraps, hang your weights onto the bottom of the webbing to ensure that the skimmer "curtain" hangs vertically in the water & pushes any bottom-growing plants out of the way. (Once again there's trial, error & blasphemy involved at this stage) Using the Algae Skimmer: The objective here is to create a long, thin, floating curtain which hangs down into the water but also breaks the surface & provides nowhere for the surface covering algae to escape as you trawl it away. 
All previous notes regarding trees, friends & wives apply & so far I've recovered more than 50 wheelbarrow loads of algae & weed from my pond. In fact I've come to regard it as a way of getting everyone in the street to fertilize my plants for me! They fertilize their lawns (& the pond) I recover the abundant plant life from the pond & use it as compost for my garden plants. It involves a bit of work - but it's cheaper than the health club! I'm now working with Rob to stock the pond with algae-eating fish & to plant beneficial, native aquatic plant species to help reduce the number of wheelbarrow loads of weed & algae I need to remove. Hopefully we'll achieve a natural balance in the near future. Well that's it. I wish you success in clearing your ponds of weed & algae. If you'd like to discuss the design or application or even just tell me how you got on with your pond clearance, drop me an email at baggers@gateway.net . Now it's time for another cup of tea?? "Duckweed" Dave Baggaley ALL material on this page is non copyrighted so pass it on. However we do ask that you give credit where credit is due in your duckweed battles no plagerism please. |
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