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2000:
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Q U E S T  Newsletter of the Madison Aquatic Gardeners Club, 3/25/03
From: John Glaeser 233-5182 NOTE: new e-mail address =

Continuation of QUEST 3/23/03 with an Iron and Phosphate story.

Mark Adams and Linda Horvath have something to share:

Linda's 30 gallon tank was producing huge amounts of algae. Her substrate was composed of approximately 1/2 inch of soil covered with wax paper, several inches of turface, and a thin layer of gravel. Water testing using a Seachem test kit indicated phosphate levels over 3 ppm (above the highest level of the Seachem test range).

Linda was changing her water 50%, two times per week. The phosphate levels continued to be above 3 ppm for three weeks. We added Fertilome chelated iron to the tank, and within a week the Phosphate level was at 0 ppm.

Linda's hypothesis was that the turface intoduced Phosphate into the tank. Mark theorized that the iron either complexed with or formed a precipitate with the P removing it from the water column therefore it no longer was detected by the test kit.

Mark then conducted an experiment. He added three tablespoons of turface to two cups of tap water (the tap water tested 0 for phosphate, before the turface was added). Mark allowed the mixture to stand for 15 minutes and tested it for phosphate, he found a level that was greater than 3 ppm. He poured 1/2 of the water into 1 glass and 1/2 into a 2nd glass.

Mark added 15 drops of chelated iron to only 1 glass. Three days later, the glass with the phosphate and iron had a precipitate covering the bottom. The phosphate level was at 0 ppm. The phosphate level in the glass which did not recieve the dose of iron remained above 3 ppm.

Conclusions:
1) Turface can introduce unwanted, high levels of P to a planted aquarium.
2) The addition of Fertiloam Chealated iron will remove the P from the water column but not from the tank. A water test will not detect P that is not in the water column.
3) Algae can still flourish in a tank in which no P is detected if the P is
present in the form of a precipitate (or perhaps in an Fe/P complex).

Jerry Weiland has an Iron and Phosphate story as well:

I can corroborate the Fe and Phosphorous interaction.  Before adding 20 ml of Kent's iron fertilizer to my 20 gallon tank I had a phosphate reading of greater than 3ppm.  Two days after adding the iron my phosphate reading is about 0.5 ppm.

The reading of iron before fertilizing was 0 mg/l.  After adding the first 10 ml of iron it was 0.1, after the second 10 ml it was 0.4, and after 2 days the reading was 0.2...perfect!

Hartman and Glaeser exchange:

Gordon: Thinking a bit on this one. If the Fe is binding that quickly with the P, then I wonder if the chelated bond between the Fe and the EDTA is really working. Chemically, the Fe cannot bond with P unless the Fe is free Fe+2.

John: True

Gordon: Maybe the chelated Fe that we use is not that strongly chelated after all.

John: Am guessing with Ferti-lume it may be chelated just enough to give the product "shelf life" in the bottle. For terrestrial plants quick release may be an advantage. In aquatics with highly oxygenated water, ferrous form is absorbed by plants for a short time and then gets oxidized fast and becomes unavailable.

Gordon: I think Jerrys experience is that the P was used by the plants. Remember that some nutrients will/can be dramatically used when a limiting nutrient is added. I have seen P go from 5ppm to nothing in one day, and you can tell the immediate difference in the plants too.

John: Jerry used Kent, which has a stronger chelation, it would seem. The product allows small amounts of iron to become available, a little bit at a time. It dramatically reduced the level of P (good), but not completely (good, as well). 0.05 ppm is a low yet desirable level, useful for plants, IMHO.
…………………………….

Product Review: AlgaeFix (Poly [oxyethylene (dimethyliminio) ethylene (dimethyliminio) ethylene dichloride). According to UW Zoology Lab Supervisor Nancy Ruggeri, this is a hormone associated with the aging process.

Lee Rzentkowski of Aquatic Specialties indicates a number of his customers are having good results using this Aquarium Pharmaceuticals product.

"It is an effective control for many types of green or green-water algae (Chlorella), blue-green algae (Aphanizomenon), Black Beard algae (Audoinella), string or hair algae (Cladophora) and blanketweed (odogonium) in freshwater aquariums containing live plants and fish."

See you Thursday……John