Bottom of the Pool Gets Dark

by Jon
(Hamden , Connecticut)

I have had my above ground pool for 5 years. I check the water and add the appropriate chemicals regularly. Although the water is clear...the bottom of the pool becomes very dark. Vacuuming doesn't help. When I at times use PH de-greaser, the pool bottom returns to it's regular appearance but only in the areas where the chemical has touched it. The bottom then has a swirl look...where some of the ph de-greaser has touched the bottom and other spots where it hasn't, from the swirling water from the filter.

When I put the winterizing chemicals in the pool at the end of the season, by the next time I reopen the pool , the bottom is spotless once again but a month or two later it begins to darken again.

No one else I know has this problem. I know it's not really a pool part problem but I thought someone might know what might be going on with the pool.

Hi Jon

It does sound a little strange, hopefully someone else has had this problem and can help out.

Whatever chemicals you are using, I would try something else. You might also try shocking the pool every couple of weeks, if you do not already.

You could also try running the filter for longer periods of time and see if this helps. Try having your water tested at several different pool stores and see if their advice differs. You might learn or come up with something new.

Hope something works.

Click here to post comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Ask the Pool Pro.

Blue/Green Pool Water In Vinyl Pool

by Amy
(Westminster, MD)

I have an above ground pool which I have had to drain down about a foot on 3 different occasions in the last few weeks. Each time I have refilled the pool with well water. The water has turned blue/green whenever I add chemicals. I have used "Mineral Magnet" which turns the water clear for a few days but then it turns right back to the blue/green color. Any idea what is causing this and what I can do to keep the water clear?

Hi Amy

I have a few general suggestions for you. First off, you are doing the right thing by only draining to one foot and refilling. No matter what anyone says never drain all of the water out of an above ground pool unless you plan to change the liner.

If you use chlorine in your pool, as many people do, you should check your chlorine level with a test kit several times a day. If at anytime the level is low, give the pool a fast boost with granule chlorine.

Try using vinyl shock treatment when the pool is first filled and at least once a week for a few weeks. If at any time the water starts to turn, add shock treatment, check your chlorine level and run the filter nonstop until the water clears up.

It is also important to keep the ph balanced. By doing this you are allowing the chlorine to be the most effective and last the longest.

It might also be helpful to work closely with a pool store, taking in water samples on a regular basis for a while. Just be sensible as to all the extra chemicals they may recommend. Some stores test your water to be helpful, some do it so they can sell you a lot of stuff you do not need. Vinyl lined pool have rather simple needs, and many chemicals can actually damage a liner.

The two biggest things I think are the vinyl shock and running the filter nonstop until the water clears.

Click here to post comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Ask the Pool Pro.


Our pool was green so used a product that caused algae to fall to bottom of pool. No matter how slowly and carefully I am, when I vacuum the sediment floats back up and re-clouds the pool. Any suggestions?


Mustard algae can blow right through most filters, that might be what is happening. It is very important to kill the algae before vacuuming. Most filter systems have a vacuum to waist port, I would use this and get as much of this out of the pool as possible, that way it will not go through the filter and back into the pool. Another suggestion is to run your filter 24/7 until the problem is gone.

Click here to post comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Ask the Pool Pro.