Pros and cons of each copper sulfate including buffered copper algacides and hydrogen dioxide (peroxide) compounds. Here is a link to some basics of algae control.http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=92633#Post92633
One of my posts from the link plus some enhancements: For wise management and effective chemical algae control and management, I am currently 'sold' on using peroxygen carbonate (Phycomycin, Pak 27, Green Clean Pro) especially in smaller ponds. Peroxygen leaves no residue, reacts quickly, will oxidize (breakdown) smallest organics, is not affected by water hardness, has minimal impact on invertebrates/fish, and helps oxygenate the pond as it reacts. NOTE that peroxygen products are often not as effective on heavy dense growths of algae as the copper based products. The peroxygen products are best used when the bloom of algae is in the early stages and not massive growths. The peroxygen products are oxidizers which means the more biomass there is the more product that is needed to get oxidation of all the target algae. It can be used effectively to 'trim the bloom' and retard early stage algae growth.
Used correctly peroxygen products can be fairly selective on nuisance scum forming bluegreen algae blooms. For filamentous algae (FA) one should treat it early when it is short and most vulnerable. This technique will require less chemical. Peroxygen products are not as effective when the algae problem is large or massive. Peroxygen at the 80% active ingredient is best IMO. The dosage rate of label is 3-100lbs/acft. For FA control higher amounts in the 50-100 lbs per ac may be needed - again treat early before the growth gets thick and harder to kill. Light doses - applications are effective on floating films of bluegreen algae. I always suggest one test the product at various concentrations / rates in small areas to determine what is needed for each particular problematic algae.
Copper sulfate contains a heavy metal – copper. Copper based algaecides have been used for many years and are usually effective and results are often quickly apparent especially for thick high amounts of algae. Copper based products always end up leaving a metal based residue byproduct in the sediments (copper carbonate). Copper carbonate is relatively stable in the environment, however it accumulates with repeated use, and stays in the pond mostly in the sediments. Other control methods should be used on heavy or dense, massive infestations. Studies have shown that copper products can accumulate is some body parts which is why water treatment plants must monitor the copper concentrations in the water when copper algaecides are used in reservoirs .
Copper based products leave copper bi-products in the pond usually the sediments which are absorptive to a point until they become saturated with copper. Then the copper products tend to stay in the water column. Copper has minor amount of accumulations in fish and pond organisms and fish are not reported as problematic for human consumption. Copper depending on concentration is toxic to sensitive aquatic animals and can kill fish eggs and fry. The higher the alkalinity the more copper that is needed for killing algae due to the copper ions binding with the water’s carbonates before they kill algae.
Peroxygen products are hydrogen peroxide and washing soda as the granular carrier. It breaks down into hydrogen, oxygen and carbonate essentially chemicals that already comprise water. Using peroxygen will mildly oxygenate the water as it works. For best results use it early before blooms become noticeable.