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WHY DO I HAVE ALGAE

and what can I do about it??

By Gail Barnhill

The Tucson Watergardeners

BE PATIENT! Algae is a plant·plants love sunlight, nutrients. Since your other pond plants have not yet spread out enough to cover and shade 60-70% of your water surface·the algae is "in control"·but not for long. You can simply wait it out·

OR TREAT IT (gently)! You can use a coagulant/flocculent (look for product names like "pond clear", "crystal clear pond", etc. , but BE SURE it states on the package that it is safe for fish, plants AND biofilters.) This product makes the small algae particles clump together and then fall to the bottom of your pond. Then skim the dead algae off the pond bottom or you will be adding more nutrients from decaying algae·to feed more algae!

You might want to suspend shade cloth over your pond, but then that will slow the growth of your "good" pond plants as well. Another product to try is pond dye, it turns the water a deep blue or black (but still clear enough to see thru), thus shading the water and depriving the algae (and "good" pond plants too, unfortunately) of needed sunlight to grow. Floating plants such as Water Hyacinth & Water Lettuce are especially good at cleaning up the water as they are using the same nutrients the algae does. Cleaning any accumulated muck or debris from the bottom of your pond will lessen the nutrients the algae like. Good spring pond maintenance anyway. Just don't clean ALL of the muck/debris out, leave a little. Also never scrape off all of the short algae clinging to the sides of your pond, it is actually beneficial to your pond and provides needed oxygen.

DON'T ö REPEAT DO NOT DRAIN & REFILL YOUR POND! If you do, you will just be starting ALL over with fresh nutrients to feed the algae, as well as stressing your fish, the other plants·not to mention your water bill·and yourself!

BUILD OR BUY A BIOFILTER. This can be done for anywhere from $50 on up (and up and up, but doesn't really have to be expensive!) A biofilter is a container filled with some type of medium like pea gravel, lava rock, old hair curlers (anything you have a LOT of and has a lot of "surface" area). Pond water is pumped thru this medium, microbiotic bacteria colonies form in the medium and feed on/detoxify the "gunk" in the water, returning clean, clear, healthy water to your pond.

OR A TEMPORARY "ALGAE FILTER" Drill a 1" hole on the side of a 5 gallon bucket, just above the bottom of the bucket. Fill the bucket half full with old fabric such a sheet (make sure it is clean and well rinsed of detergents and softeners!) . Set the bucket close to the edge of the pond with the hole you drilled facing the pond. Run the tubing from your pump into the top of the bucket (you may have to purchase a longer piece of tubing) and turn the pump on. When the fabric is clogged up with algae and not draining as fast as it is filling, replace it with clean fabric (a sheet is nice for this as you just remove the dirty section and put the clean section in its place). Don't let this "algae filter" run when you're not around to keep an eye on it as it could clog up and end up emptying the pond! Depending on your pond and pump size this can take anywhere from a day to a week to clear the water. The great part is that you have removed the algae without changing the chemistry of your pond water!

WHAT ABOUT "STRING" OR "HAIR ALGAE"? Treat this type of algae by submerging a leg of a nylon stocking filled with barley straw (beg the "scraps" from a feed store·or buy a whole bale for about $7). Add a couple of rocks to the stocking heavy enough to keep it from floating to the surface. It's thought that the barley straw lowers the PH of the water (may take a few weeks to work), to the dismay of string/hair algae! It is a good idea to "twirl" this algae out of the pond as well using a bottle, vegetable or toilet (clean, please!) brush.