Question with installing tarp for shade


Jul 21, 2010

I was wondering will installing a tarp (to provide shade) 10 feet above the ground over my pool have any negative side-effects on my pool? Meaning, does pool water benefit anything from the sun's UV light at all? I hear that it will actually make my chlorine last longer but I might have a chance of "black algae" from the shade. Is this true? Please advice! So far I found this forum to be the most helpful around.



20k gallon concrete Pool
All chemistry properly balanced ... ockType=G4


TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
Welcome to TFP!

Overall, it will probably be a net positive effect. There will be some disadvantages, but they should be minor.

Adding a cover that greatly reduces the amount of direct sunlight shining on the pool will have several small effects. It will noticeably reduce the amount of chlorine you need to use each day. It will make it more likely that you will have problems with CC going above 0.5. And it will slightly change the odds of getting various kinds of algae, some more likely others less likely.


Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
Houston, Texas
My pool stays in partial shade due to house and tree position around the pool. If you only shade a portion of the pool instead of covering the the whole surface you should not notice any negative effects from blocking sunlight.

Now the tarp you are looking at may not be very pleasing to look at or last very long. I would also be concerned about it holding water and tearing. Check out some of the various shade sails that are available. This may be more like what you would be looking for.
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