Continuing my anti-rant:

Quote Originally Posted by katw78
I suggest that you look outside your narrow-minded box and do more research of your own.

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[color="black"]www.hthpools.com[/COLOR]

Algae does not cause disease. It is a plant that turns sunlight and carbon dioxide into food and provides nutrients for bacteria which can then multiply rapidly (and may cause illness). When there is algae present in the pool water, the chlorine is used up rapidly trying to combat its growth. This process has a tendency to raise the pH, thus decreasing the efficiency of the remaining free chlorine.

This is misleading. Even if algae is harmless to humans, what it DOES do is consume all the chlorine preventing sanitation of the pool. The MOST important job of chlorine is to sanitize fecal matter--and everyone who enters the pool leaves a tiny, tiny bit. If you have no chlorine to metabolize it, you have a MAJOR source of disease at hand. Diseases like Typhoid, Typhus, Cholera, etc spread in contaminated water. Mosquitos can breed in unprotected water.

By using up all the chlorine, the algae leaves your pool susceptible to all these, and more.

Unchecked algae growth can turn the swimming pool cloudy or makes the pool water green and results in foul odours and tastes. Black algae, which is more difficult to control than green or blue-green algae, can also stain the swimming pool's walls and floor.

Prevention is better than cure. Adequate levels of free chlorine will prevent algae from growing out of control.
When algae growth is noticed, it requires harsh treatment.

Nothing to disagree with here.

Usually shock treatment with chlorine or an algaecide is recommended. If the pool has a mineral sanitiser such as the Pool Wizard installed, algae growth is a sign that you need a refill. Algae cannot grow in water sanitised with the Pool Wizard, provided the water is properly balanced.

Give me a friggin' break! Yet another shilling for a product...How is THAT evidence???

www.havuz.org

TOO LATE TO PREVENT IT...HOW DO I KILL ALGAE?
A: First off, balance your water, paying particular attention to pH. Secondly, check your filter system and clean if necessary. Adjust valving for optimum circulation and allow it to run 24 hours a day until the pool clears. Turn on automatic cleaners to help stir things up. Backwash as necessary.

For suspended green algae, shock the pool...hard. Put in as much hypochlorite as it takes to turn the pool a cloudy, bluish/gray color. Brush the walls and floors towards the main drain. Backwash the filter when the pressure gauge indicates the need. Using a flocculent may be a good choice if the pool is extremely "swampy".

Again, somebody's web site pushing a product. Mostly good advice, but using a floc at this time is just plain WRONG! You use floc only under circumstances where all other causes of cloudyness have been ruled out. You don't just throw in chems willy-nilly. You use them to address the SPECIFIC problem they are designed to handle--and floc is NOT designed to handle this.

If you cannot see the bottom of the pool, and it is filled with leaves and debris, it may be wise to drain the pool, acid wash and refill it.

This is going to work REALLY well on a vinyl pool! Watch the acid melt the liner! This is flat out STUPID advice! Get a "leaf rake" (a deep-bagged skimmer with a squeegee) and apply some elbow grease to get the junk out! Draining pools completely is VERY dangerous. If there's a high water table, a fiberglass or concrete pool can float out. You NEVER fully drain a vinyl pool unless the liner is brand new or you are replacing the liner.

After the chlorine level has come down below 5 ppm, add an algaecide and brush the pool again. When it all settles, vacuum the pool (to waste, if possible). Check and rebalance the pool water if necessary.

Been down this road. Why should I discuss it again?

For algae which is not suspended, but only clinging to the walls, follow the same advice above, first shock with brushing, then add an algaecide, brush again, vacuum to waste (preferred) or vacuum and then backwash the filter. Use of a steel bristled brush is recommended for algae on plaster pools (use nylon brushes on vinyl). Filter, Filter, Filter.

For black algae, the brushing part is very important. You must tear through the protective layers so the chemicals can destroy the plant from the inside out. Pumice stones work well to knock off the heads of black algae. (Don't forget to vacuum them up later, and backwash them out of the filter ASAP).

Blah, blah. Nothing special here.

Also effective on the black algae nodules is sprinkling granular trichlor over the spots (of course if they're on the wall this is next to impossible). Rubbing the spots on the walls with a trichlor tablet or stick can also be effective to knock off the heads and get trichlor directly to the roots. Follow up with a dose of copper algaecide, or high strength polymers. Simazine, an herbicide, was a very effective black algae treatment, but is no longer available in America.

Again, this is INSANE advice. Rub tri-chlor on a vinyl pool wall?? Gee, will it bleach it white or dissolve from the acid? No advice to wear rubber gloves and a mask while doing this? I sure don't want to touch a wet puck--that thing will BURN your skin! Next they recommend copper algaecides...With their advice, maybe you ARE better off just draining that contaminated water off after all!

If algae has been an ongoing problem in your pool for several years, you may do well to drain the pool. Many years of algae builds up dead algae cells and lots of other solids in the water that contribute to its rejuvenation. Acid washing and/or pressure washing is preferable once drained, to kill the roots of the algae embedded in the plaster. NEXT: change the sand if you have a sand filter or change the cartridge if it is a cartridge type. Sand should be changed every 5-7 yrs (or every 2 if you use baquacil), and cartridge filters should have new elements every 1-2 years. If you have a DE filter (good for you!), you should remove the elements, spray clean, soak in a 10:1 water/bleach solution, rinse and replace. A well functioning filter will prevent algae.

I've had enough of this Lucy Van Pelt advice. I ain't Linus dragging around a blanket! This is more and more nonsense. I'm tired of typing to refute every asinine assertion in this post.

Another item to look at is the method of sanitation and the type of filtering you have. Far too many pools out there were sold with marginal filter systems, meant to run 24 hrs per day. Well, these systems get old and tired, or the new owners only run it 12 hrs per day (or less). For good algae prevention, we need a combination of good filtration, sanitation and circulation. It may be time to consider changing the old pump and filter. It's cheaper and easier to pay a little up front for more chemicals, electricity or better equipment than all the money and aggravation spent on fighting algae blooms.

www.poolcenter.com
Well, this was an exercise in frustration. Almost all the bad advice we've seen over the years here that pool stores and pool chem companies have distributed has been collected here!

That's not proof, that's not scientific evidence. That's certainly NOT a sign that our minds are closed. That's simply the same old WRONG garbage we have been teaching people to avoid. You've introduced NOTHING new here.