Brown pool water can have several sources.It may be mineral or may be living, breathing algae.
Your automatic pool cleaner is the algae slayer
Poor circulation is one of the leading causes of algae growth and brown pool water. Too little free chlorine is the other and algae will grow despite adequate chlorine if the circulation is poor.
Regular use of your robotic pool cleaner circulates the pool water and distributes your expensive chemicals with great efficiency.
But I use Algaecide!
Funny, I used to pour algaecide into my pool all the time. THEN I noticed, I only had algae problems when the chlorine was allowed to get too low. I stopped using algaecide, paid better attention to the chlorine and have had clear water ever since.. Algaecides aren’t cheap, and I save enough to pay for disposable bags for my robot
Algaecides do have a place. Some Algae, once started, is difficult to eradicate.
True “Algae” Story
Went on vacation and upon my return I noticed pinkish brown pool water. A thick gooey growth was visible in the water and growing on every thing in the water. I shocked, shocked and shocked more but it kept growing.
The pool store gave me “pink algae” killer, a silver based algaecide. It worked great and in 2 weeks I had clear water again. I have since learned that “pink algae” is not algae at all, it is bacteria growing out of control. Of course the chlorine level was allowed to drop to nothing while I was away, thus the bacteria bloom.
I worried about the pink coming back, so I threw a piece of sterling silver into a mesh bag with a piece of copper hoping this would help sanitize the water of bacteria and algae. This may or may not have worked but It DID lead to a new problem…
Honey, I ruined the pool!
Upon opening the pool for a new season, I found all the plastic around the skimmers and returns and everywhere else had turned black. The liner had hundreds of black spots. Every leaf, every dead worm left a black shadow on my liner. I tried many cleaners and could not get the black out.
Then I had the water tested and the pool store noticed a large amount of metal. He sold me a METAL SEQUESTERING AGENT that I promptly poured into the water. In three weeks time, ALL the stains were gone...and so was the bag of copper and silver. Live to learn.
My favorite method to determine the cause of cloudy or brown pool water, comes from,
poolmanual.com (new window). “f you are not sure whether or not an apparent growth is algae, here is a simple test: Play doctor and take a sample of the apparent growth from the pool. Place the sample in a clear jar filled with pool water. Then, add a teaspoon of diluted chlorine-based shock (this must be Calcium Hypochlorite or Lithium Hypochlorite, as both contain some chlorine. Potassium Peroxymonosulfate, which is a non-chlorine shock, will not work). Cap the jar and shake the sample in your hand. Set the sample down and come back within 1 hour. If the water has a green tint, you have a copper stain, and not Green algae. If the water has a brownish-red tint, you have an iron stain, and not Mustard algae. If the water has a brownish-black tint, you have a manganese stain, and not Black algae. If, however, the water turns clear, then you have algae, and you had better evaluate the color of the algae in your pool and begin treatment immediately.”
Poolmanual.com is a great resource on pool care and I hope they don’t mind I used their material.