Welcome! Pool Route Sales is the ideal place to start a new career in the swimming pool industry. News Bulletin Stay up to date on the events and information in the swimming pool industry. Testimonials Here what others have to say about Pool Route Sales. News Bulletin If algae’s back, you probably never killed it! "Try this one," a reader writes. "I have this pool with a customer who refuses chlorine and has spent over $20,000 upgrading for an ozonator. There's black algae growing in the grout. I brush it with a wire brush every week. It keeps coming back. When the customer is out of town, I throw in 2-3 pounds of dichlor. When she’s there, I visit 3 times per week and add 25 small bromine tabs for each day. "Water is about 6 months old. pH is low ... total alkalinity is 100 ppm ... calcium is high. Filter and pump are a couple of years old. Filtration is not the problem. Black algae in the grout is the problem. Any reasonable suggestions? My only thought is to remove the grout where necessary and replace." Let's start out by saying that brushing once a week is not going to get rid of a stubborn black algae bloom. By its very nature, black algae is resistant to chemicals and will only die after sufficient "poison" is allowed to penetrate the plant's roots. This means superchlor-ination and brushing ... and brushing ... and brushing some more. Ozone will not prevent algae. You must have a halogen (chlorine or bromine) residual in the water to prevent algae. But once you have a bloom — particularly a black algae bloom — you must use heroic means to get rid of it. What you are doing now by weekly brushing is simply "mowing the lawn." You are removing the top layer of algae but are doing nothing to the roots or the spores from which algae grows. When you return, the algae has re-established its toehold in the grout, and you are back to square one. When confronted with an algae bloom, the first answer is to superchlo-rinate and follow that up with vigorous — and frequent — brushing. We’re talking daily brushing; the more the better. To superchlorinate, bring the level of free available chlorine up to between 5 and 10 parts per million, and maintain that level for at least 4 hours. Vigorous brushing will pull the algae out by the roots and will expose all of it to the chlorine, instead of just the top layer. Also, brushing will remove the slime layer that forms on top of the algae as a defense mechanism and protects it from chemical invasion. The filter should should be run 24 hours a day while you wage your war on algae. Once it disappears, don't take it for granted that it has all been killed. Even though the algae can't be seen, there are still plenty of algae spores just waiting to start a new bloom. Algae reproduces by cell division, doubling in number every few minutes. So in a couple of hours, one algae cell can become literally millions. And in a week's time, billions and billions of cells could be present. That is why brushing must be kept up well after you think that all the algae has been killed. Experts advise that the routine be continued for a week to 10 days after the algae disappears. Simply continue to treat the affected area as if the algae were still there. Keep brushing, running the filter and treating with chemicals. As for the filter, make sure that it has been cleaned or backwashed and that there is good flow to the entire pool. You want the chemical-laden water to reach every single nook and cranny. A "blind spot" in circulation can lead to an algae bloom in that portion of the pool. This explains why some pools seem to be more prone to algae attack than others: The pool's hydraulics may not be best for proper circulation. Nevertheless, as the service professional, the problem is yours. You can make up for hydraulic deficiencies by more brushing, more vacuuming and possibly making hydraulic improvements, such as directional return fittings or diverter valves that can properly balance the suction between the skimmer and main drain and the return lines. You can also treat the problem by applying chlorine granules directly to the algae areas or rubbing the area with a trichlor tab. There are tools designed specifically for this purpose. Chlorine is a highly effective spot algicide. You might also try placing a chlorine tab in a plastic bag, cutting a few holes in the bag and hanging it in the water near the algae-affected area. Don't do this in a vinyl pool or near any surface that can be bleached by the chlorine. Finally, purchase an algicide that is especially designed to fight black algae. You may have to do some testing until you find the one that meets your specific needs, but as far as we know, there is no strain of algae that is totally immune to chlorine and all commercial algicides. Make note of the type of algicide you are using until you find one that works for you. Remember: there are several different "families" of algicide out there, and not every one will work in every situation. Contributed by: SERVICE INDUSTRY NEWS 3-21-03   Back to the News Bulletin