Algae That Won't Quit!

[lauraneal72]

Certainly sounds like a persistent case of algae. My only concern is that green algae is not that hard to kill as chlorine is very effective at killing that particular kind of algae. So that makes me think one of your chemical levels is off, like too much or too little CYA, or there's some problem with your circulation due to a clogged filter or returns that are not pointing in the right directions. Dead spots in the circulation can allow FC to drop below minimum values and give algae the time to reproduce. However, at 20ppm FC, you should be seeing some clearing.

Please post a current reading of CYA and then we can advise on a better strategy.

Also, did you recently use the phosphate remover or was that something that was just tried a long time ago? Do you happen to know what phosphate levels you have?

I took a picture and from the balcony on our upper level, bright sunlight on it, and after I swept, it does look better than it has. I think I'm winning, it's just so slow. The deep end is a dull green and I can barely see the bottom if I look really hard. The thing that worries me most is that the algae was still bright green when I was brushing the pool. Usually it gets to be a grayish color, so I don't like that.

I retested the CYA and it's between 50-55, so about what I thought.

The phosphate remover was last used over a month ago, but I have plenty left and can put it in since I have it anyway. We live with a lot of tree debris, so more phosphates are being added daily. I can take a sample to the pool store to check the phosphate level.

 

[jblizzle]

Forget the phosphates ... follow the SLAM Process process.

 

[lauraneal72]

This is what I want to see, just for comparison.

 

[mknauss]

Your retest of CYA you stated a range up to 55. Use 60. Thus, your shock level is 24 FC. You might be surprised how much difference that makes.

Good luck.

 

[JoyfulNoise]

I took a picture and from the balcony on our upper level, bright sunlight on it, and after I swept, it does look better than it has. I think I'm winning, it's just so slow. The deep end is a dull green and I can barely see the bottom if I look really hard. The thing that worries me most is that the algae was still bright green when I was brushing the pool. Usually it gets to be a grayish color, so I don't like that.

I retested the CYA and it's between 50-55, so about what I thought.

The phosphate remover was last used over a month ago, but I have plenty left and can put it in since I have it anyway. We live with a lot of tree debris, so more phosphates are being added daily. I can take a sample to the pool store to check the phosphate level.

View attachment 66252

We can deal with phosphates later. Whether or not they are important depends on the level in the pool relative to other nutrients (such as nitrates) but, in most pools, the water is phosphate-limited anyway. Removing phosphates does not fix an algae problem, it is merely insurance against future algae reactivity. So keep the phosphate remover for later and we'll deal with it AFTER your pool is clean and clear and you've had the ability to enjoy it for more than 4 swims....

I would suggest you raise your FC up to 24ppm or even as high as 28-30ppm. Keep your eye on the filter and only backwash when you've gone 25% over clean pressure. DO NOT ADD the DE until the green is gone! Adding DE now would just clog up the filter too soon. Save the DE for later when you need to get past the cloudiness stage. Sand filters are good, easy filters to work with but they have an achilles heel - they don't clear pools up very fast. When you get to the part of the SLAM process where the water is just slightly hazy, that is the point when you want to use DE to polish the water and help capture the fine debris (aka, dead floating algae).

Keep at it! SLAMs can be painful and you've certainly had a rough time of it.

 

[lauraneal72]

The pool is looking good today. Finally, I'm winning the algae war! When it is time to add DE to the filter, can I add it through the skimmer? For some reason I was thinking I had to open the filter and that just seems silly now that I've thought about it a little while. I know there's an article about it, but I haven't had time to research it. So, the water isn't completely clear, but I can see the bottom pretty easily in the deep end. Probably almost time to add DE if I'm going to do it, right?

 

[JoyfulNoise]

Add it through the skimmer about 1/4cup at a time until you get a 1 psi pressure rise on the gauge. Most filters don't need more than 1 cup