Algae in salt water pool, need advice

nanhsotJuly 14, 2007

Our pool has been functional since last August (though we are STILL working on things around it, the never ending project!). Water looks clear and beautiful, generator works great, we add acid regularly as we live in a hard water area. All in all we're pleased with our salt water pool, however we have an ongoing problem with algae setting up in the cracks of our grout.

The sunshelf and underwater seating areas are all constructed of native rock, I'll include a photo below as an example, photo is a year old so things look much different now, but it will give an idea of surface. The posts sticking up are now part of a shade structure, so ignore that.

Over the winter we had an issue with algae in the negative edge basin, is it possible there is still some in there that is getting into the pool? We treated it with algaecide and it seemed to clear up, but now I'm noticing algae creeping back into the grout area around the stones on the sundeck. I have been scrubbing regularly.

We are in Texas, and as those of you here know, it's been a RAINY spring/summer, could that be contributing, and if so, what can be done to prevent?

Any thoughts on why this is happening and how to completely prevent?

Here is a link that might be useful: sundeck

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If you don't have a chlorine floater in your catch basin, you should probably load one up and toss it in there. My basin tends to get algae pretty easily as well - I believe it's because it's shallow and small, so the chlorine burns off quickly and the water gets very warm. No problems since I put a chlorinator in there.

I suspect the same problem applies to your baja shelf - the chlorine is burning off during the early part of the day giving algae a chance to take hold. You might want to try running the pump briefly (30 mins or so) a couple times during the day to change the water over the shelf. Also be sure to check your free chlorine level, and check for phosphates.

    Bookmark   July 14, 2007 at 2:12PM
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You need to make sure you have enough chlorine in the water and the stablizer (CYA) level is correct. You said you have a salt pool so you need to check the setting on your SWG and make sure you have at least 3PPM chlorine (actual number depends on CYA level).

    Bookmark   July 14, 2007 at 7:10PM
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Algae in the grout line is almost always a non-consistent chlorine level. Also, clean the tile regularly. That will help. Most tile cleaners are acidic in nature and that will knock out thing before they take hold. A good algaecide is probably a good start (I use Sea Klear, algae prevention and remover) It has a 90 day residual. If you have an in deck auto filler, the odds are great that there is algae in there and that is a continual source of algae spores into the pool even when the pool appears alge free. And, as stated in the other post, check for phosphates which are the food source for algae.

    Bookmark   July 14, 2007 at 11:44PM
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I have a similar pool and like your my pool is about two years old. I have had a similar problem with my baja shelf. We only get algae on the baja shelf, no negative edge. I think the fact the the grout between the stone is black and of course the shallowness and heat contribute to the problem.

Good sugestions by all. I also noticed that the problem may have been agravated once we added more CYA, which is about 100 now.

BTW, Do you have any problems with your mortar in your coping? See my post on Type S mortar.

I think that

    Bookmark   July 15, 2007 at 3:07PM
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First and foremost do not add chlorine into your pool by any other means than your SWG.
1. Take a water sample to Leslie's or similar pool store and have them test the water.
2 Your salt level should be within the 2400ppm to 3300ppm range
3.Have water tested for phosphates 300 or above that is your problem. Get Phos Free+ Pool Perfect and follow directions
4.Make sure CYA is at the right level 50 to 100. Less than than add Conditioner lbs depend on you pool capacity.
5.Chlorine level s/b at least 3.0 Make sure you SWG is set to 80% until you get chlorine level up.
6 If you have hard water you may have scale in the SWG. That will reduce efficiency of SWG. Unscrew the ends of the cell and take it off and inspect cell for calcium deposits. As a matter of playing it safe mix a solution of 4 parts water and 1 part muratic acid. Use a container about the same size as the cell, so it can be immersed into the soution. Place cell in solution, cord out of the solution and keep the cell there until the solution stops bubbling. You should do this every 2,500 hours of operation.
Once you do all this your water should be in good shape.

    Bookmark   July 16, 2007 at 4:01PM
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Why should someone not add chlorine to their pool by any other means than the SWG?

    Bookmark   July 16, 2007 at 6:37PM
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I've been going by the BBB method that kurtv uses and have had a great pool ever since. I think that you need to get your chlorine levels up. The SWG makes chlorine, so why can't you add some already made to get the pool up to shock levels?

Last year I went on vacation and left my the fathers to take care of the pool. They dumped shock and yellow out in it and I came home to a green pool. I immediately started reading and decided to try the BBB method. After all, the chart was easy to read and there was lots of information there...more than what I got from any other site. I stopped using the chlorinator that came with the pool and started using bleach. I made sure to rinse the filters often until I didn't see anymore green. It has been a breeze ever since. The green has never reappeared.

I will say, that I took a sample to Leslie's to see what they said, too, and if I had listened to them, I would have added a ton of chemicals that I didn't need. I followed the info on the BBB site, took the water to a local pool store, and they told me I was doing great. (I buy my acid from them...but that's it).

The only thing I don't like is that I can't register on that site. I was getting ready to sign in and they closed the new registrations on that day. If I have a question, I post here.

The only thing that I got in the beginning was calcium on my tile that released from the new grout. I use vinegar and a scrub brush to get rid of that.

Good luck!

    Bookmark   July 16, 2007 at 9:32PM
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Try It was created as sort of a backup for poolforum in case that site went down permanently (and because new users couldn't register). Many of the really knowledgeable poolforum members are very active there and the site has really taken off.

Here is a link that might be useful: Trouble Free Pool

    Bookmark   July 17, 2007 at 12:13AM
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Thanks, kurtv! I'm happpy I checked in here today!

    Bookmark   July 17, 2007 at 10:43AM
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What is the BBB method that kurtv uses?

    Bookmark   July 31, 2007 at 6:18PM
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