brown stains on bottom (pebble tec)

[newpoolontheblock]

I work for a major pool builder and see this issue every day.

What you are describing is what is known as Dirt Scale.

Basically, a thin layer of calcium buildup has trapped the dirt on the surface of the pool. This is the reason you cannot brush it away. It's sort of like painting a coat of polyurethane over a spot of dirt on the wall. Unless you break down that calcium buildup, that dirt is not going to go away.

Most people only pay attention to how clear the water looks. If the water is clear, the water chemistry is good. It's not as simple as that, but it is easy.

If you don't already have one, get to your pool supply store and purchase a chemical test kit. The test strips will work, but if you want a more accurate test result, get a kit that includes the drops.

Once you have a test kit, you will want to test the water at least 2-3 times a week. The most important things to pay attention to are PH, Total Alkalinity and Hardness. It is important to keep the PH around 7.2-7.6 to avoid the buildup your seeing.

BTW, there is a very simply way to get rid of that scale. It will take some time but it will work if you put the time and effort into it. All you need to do is drop your PH level to about 6.8-7.0 and BRUSH BRUSH BRUSH. Test the water even more frequently during the process. Like I said, you probably won't notice any improvement right away, but over the course of a few weeks, it will start to fade away.

If you want a "quick fix", you can contact a pool service company (one who knows what they are doing) and they can drain the pool and do an acid wash which will do the same thing as the first method, only faster.

Good Luck!

My pool is only two months old. I noticed these same brown stains on my pebble sheen surface the day after adding hardener to the water (as instructed by the pool experts at Leslie's). Could the calcium in the hardener have built up or left a residue and caused these brown stains? If so, will this method you describe in your post work on getting them off?

[Larry]

The pool store recommended adding a hardener because they probably measured the water and found it too low.

If the pH or alkalinity were very high when you added the hardener it could have resulted in scale forming very quickly. Scale that rapidly appears is often discolored.

First of all we need to know why the scale formed, so we need to know the test results for the following:

• pH
• total alkalinity
• calcium hardness (or total hardness)
• free chlorine

and also what chemicals were added prior to the stains appearing.

Larry

[Little Bird]

I have been working with these issues for 12 years. I read some comments and they all make sense. However, some problems are bigger than what we are talking about. Usually, it just happens to pools that you really can't control the PH. Then you ask yourselves: how come? If I have everything under control (PH, chlorine, alkalinity, stabilizer, calcium balanced), it is impossible to not keep them at the right or acceptabke level, RIGHT???
WRONG. Did you consider leaks? Well water? Bad or no circulation???

[paulbest]

Swimming pool stains can be caused by metals in the pool water, rust coming through the wall or by any organic material. The first clue to identifying the type of pool stain is the color of the stain.

A greenish-brown colored pool stain is generally due to something organic such as leaves or mud sitting in the bottom of the pool. reddish-brown or rust like appearance are likely caused by metals.

To prevent pool stains, keep pH and alkalinity balanced, to avoid mineral stains (from low levels), and scaling stains (from high levels).

For algae prevention, proper pool pH and alkalinity will allow your sanitizer to work more effectively. Remember, Pool Stains and Pool Algae don’t just happen, they need certain water conditions to occur. Take care of your pool’s pH and alkalinity first and problems with staining or algae will be easier to manage.

[tessa]

Could be algae - need to get an algaecide and liquid chlorine, brush the pool real good, put algaecide and liquid chlorine in then let fi;ter run until pool water is clear.

Cheryl

Our pool was just re-plasterd and tiled this year, we have the same problem, never had this before...Pool water tests well, we shocked it beginning of the week, retested water...is good, PH is a tad low, so perhaps we will try brushing the crap out of it....Sure as heck do not want to mess up this new plaster......its annoying at best