How can I have algae when maintaining at 7ppm

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simonoaks

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LifeTime Supporter
May 28, 2015
322
Juno Beach , Florida
So pretty frustrating.

I maintain my pool year round , and keep it at fc 7. I test 3 times per week, add acid , baking soda , cya etc as necessary.

To prep for the long days of sun, about 2 months ago I tested for CYA and it was 30ish, so, I did an overnight test (been stung before where I raised CYA to 80 then found I had algae !!). All was good so I added CYA and it was at 90.

Pool still constantly maintained at FC 7.

Today, I noticed that it just kinda did not look quite as crystal blue. Then when I swept it, I found out why - huge plumes of yellow dust !! I could see the streaks left my the brush.

So, I do not think I should even wait to do an over night test tonight, I know I have algae as I just saw it plume up into the water.

How is it possible to get algae when keeping pool at fc 7 ALL THE TIME?

Now that my CYA is at 90, should I drain before SLAMing? I have done about 9 SLAMs in the past an most at 80 CYA and it is a pain (mainly because it is literally impossible to overnight test accurately , so you cannot really maintain , you have to let it drop to testable level)

If I do need to drain, how do I figure out how all the valves work in order to drain the pool ?

Off to publix now to go buy 20 gallons bleach ! Might as well get a head start

thx
 
If your CYA is 90, 7 is the minimum FC. If it dips below 7, you open the door for algae. With CYA of 90, I would target 12 as my normal FC.

Why are you keeping CYA so high?

Now that you have algae, you will need to SLAM. You can SLAM at 90 CYA, but it is easier to do with a lower CYA.

Before SLAM, You need to check PH. Should be at 7.2 before you SLAM.

Reading material:

SLAM
Chlorine/CYA Chart
 
You don’t need to drain the whole pool. I don’t know what kind of gadgets you have, but you could always resort to siphoning. Toss one end of hose into pool, other end is below water level. Start the siphon with suction(don’t drink the water!) then let it flow!

I have a nifty little pump I got in Amazon that is a champ at draining water.
 
You might have 7 FC where you test, but there could be areas with poor circulation that have considerably less. That's how algae grows.

Once you get the algae liscked -- or even now -- get yourself a wall whale brush or something similar. They move some water. If I stand at one end of my pool and give a short sweep, I can wait for the count of three and then see the wave come up at the far end, that's how much water they move. You can be sure then that even with minimal brushing, your water is going to be well mixed.
 
Ok, Thx.

I am pretty expert at the SLAM part, unfortunately lol.

I just tested again, 1 hour after brushing all the algae into the water, and SWG is maintaining at 7 FC. I find that odd, because every other time I have had algae , my first red flag is when FC is not being maintained ( This of course is also an indication of drop in CYA over time too) .

I just tested CYA again it it was at 70, which is about right, it has dropped about 20 ppm in 6 weeks , which is usual for my pool.

So good news I only need to raise from 7 to 28 , so only 4 gallons needed , for now.


Just ordered the wall whale from Amazon for $30 . thx
Could the fact that , here is South Florida, we are getting big storms every afternoon for a week with several inches of rain a day, make algae for likely ?
 
Nope. I am in Florida too, and we’ve had tons of rain. No algae in my pool!

The problem is that you are keeping your chlorine too low. You need to target above minimum.
 
kellyfair said:
Nope. I am in Florida too, and we’ve had tons of rain. No algae in my pool!

The problem is that you are keeping your chlorine too low. You need to target above minimum.
Click to expand...

I am above. CYA of 80 , is target FC of 6. I am 7-8 every day. So if my CYA is 70-90 (who can really ever measure that within 10???!!! lol, I NEVER can) then my fc should be between 5-7 . Bearing in mind CYA 90 is probably 80-85 and always drops over time anyway , then FC 7 for CYA 70-80 should be fine, right ?

Anyway, just got back with 10 gallons of bleach and a box of Stella ....fun times lol

At least wife and kids are away on road trip now school has finished , so I can SLAM in peace and not keep to safe swim levels.
 
Sorry, I missed that you have a SWG. So you are right, you are keeping FC in a good range. IF your CYA is accurate.

Are you testing CYA like this:

Follow this method: In sunlight, back to the sun, fill tube to first line. Quick glance, don’t stare! Still see dot? Fill to next line, quick glance. Still see dot? Repeat. The first line where you don’t see dot with a QUICK glance is your CYA. Maintain proper FC level accordingly.
 
kellyfair said:
Sorry, I missed that you have a SWG. So you are right, you are keeping FC in a good range. IF your CYA is accurate.

Are you testing CYA like this:

Follow this method: In sunlight, back to the sun, fill tube to first line. Quick glance, don’t stare! Still see dot? Fill to next line, quick glance. Still see dot? Repeat. The first line where you don’t see dot with a QUICK glance is your CYA. Maintain proper FC level accordingly.
Click to expand...

YEs, CYA test is always been a huge pain to me. All I ever see is the concentrated white glare that forms in the middle of the tub and prevents me seeing the dot. I lose it a lot after the 80 mark.

I still do not understand how in this age of science there is not an actually chemical test like PH, FC , etc.

Anyway, Just dumped in 5 gallons of bleach , scrubbed the whole pool again and now at FC 34.....it is war lol

I like to go over the maintain level initially, because in my experience, the initial 2 hr drop is a good indication of how bad the algae is.

I have had it in the past where it will consume 15-20 ppm in the first 1-2 hrs and other times where it only drops 5-6 .

We shall see.

I have an empty house, gonna go play some music REALLY load , and test again in 2 hrs. Will report back.
 

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Update:

Brushed pool again, it definitely has a greenish/ blue hue to it, cannot see bottom clearly at deep end like usual.

Just tested, FC at 31.

So pretty happy with that, only lost 6ppm in 5.5 hrs, so algae problem not too big. It now means I am at maintain level throughout the night. Which is why I think it is worth going 10ppm over recommended SLAM number initially, it allows the fast consumption that always happens , without dropping below the maintain level.
 
Actually, the higher you dose over your proper SLAM level for your CYA, the faster you lose FC. it’s not really helping.

So, using the quick glance only, are you hitting on 80 as your CYA?
 
Just trying to learn something here. I want to make sure I didn't miss anything as I am still trying to learn about algae. So please ... experts.... chime in here for me. These are just questions popping up in my head here....just questions I need to know the answer to. It will help me in the long run.

If the FC has been within range all this time, how did simon get algae? Could this be a filtration thing?

Is it possible that some areas of his pool is not within FC range, while other areas of his pool is within FC range?

I read all the posts and I'm just trying to figure out what happened. That way, I can learn from this. Could anyone give me heads-up as to what may have happened here?
 
kellyfair said:
One concern I have is the uncertainty over the true CYA level.
Click to expand...
I know ! ALWAYS been a pain . As I say, I cannot understand why there is not an accurate chemical test , instead of a subjective visual test. I am SLAMing at 80 level to be safe.

6.50 am
FC 24 (dropped 7 overnight )
Added bleach and scrubbed again
7.25 FC 31

Quick question: does the expiration date on the reagent 0871 matter ? My "new" backup bottle say exp June 2016.
 
"Quick question: does the expiration date on the reagent 0871 matter ? My "new" backup bottle say exp June 2016."

Yes. Reagents should be replaced every year. Order new reagents now.

Take care
 
I bet it’s the cya- possibly much higher than you imagine. Losing over 20% of your cya in 6 weeks seems like an inordinate amount of rain. I inherited my pool 2 years ago and the cya was above 200 which gave me algae at FC=9 until I did a partial drain and got it down to normal. As an aside I have found that when battling mystery pool problems it usually has something to do with testing error. ar
 
I've been thinking..You have to maintain your target FC range which is dependent on your CYA. Thus, knowing your TRUE CYA level...after SLAM, etc, is imperative in maintaining your pool with the correct FC range. Just a thought.

Mendy48 said:
Just trying to learn something here. I want to make sure I didn't miss anything as I am still trying to learn about algae. So please ... experts.... chime in here for me. These are just questions popping up in my head here....just questions I need to know the answer to. It will help me in the long run.

If the FC has been within range all this time, how did simon get algae? Could this be a filtration thing?

Is it possible that some areas of his pool is not within FC range, while other areas of his pool is within FC range?

I read all the posts and I'm just trying to figure out what happened. That way, I can learn from this. Could anyone give me heads-up as to what may have happened here?
Click to expand...
 
Mendy48 said:
I've been thinking..You have to maintain your target FC range which is dependent on your CYA. Thus, knowing your TRUE CYA level...after SLAM, etc, is imperative in maintaining your pool with the correct FC range. Just a thought.
Click to expand...

I understand, but CYA test is so freaking subjective ! I bet EVERYONE is only really +/- 10 ppm.

I did the CYA test 10 times today and got between 85 and 65.
Why is there not an accurate test, like FC ?

Anyway, not getting any plumes when I brush now, pool is back to looking blue, will continue SLAM and test again tonight.

I have noticed dark green seaweed colour (I think algae ) in between about 20 of my tiles above the water line. They are about an inch long and 1/8 inch wide and when you scrape of with a finger nail, it is spongy. It goes white when I drop it in bleach so presume it is algae, is this common ?


On one last note, a quick one and to save opening a whole new thread, I have a new Hayward filter casing (my current one has been on last legs for a while and just now I cannot get the lid to tighten back on). i have had the backup one for about 2 months, so now time to swap it out.

I do not have a tool to undo / redo the connectors for the input and the output to the cell. I think it is about 3.5 inches and connects the plastic pipes into the filter casing. Does anyone know what the name of that tool would be , so I can go buy one ?

thx
 
Buy the stand alone cya test tube and mixing bottle, it is much more accurate and easier to keep the tube in full sun than the k2006 tube. Cya is measured only at every 10. After measureing cya use the next 10 higher because your have a higher risk pool. Check your lights and ladders for hidden algae. If everything above doesn't work and you still get algae after aobth or two might use polyquat 60 as a bandaid, but try to treat the problem and not the symptom.

The cya test is as it is because of chemistry, there is nothing currently found that reacts with cya as the others do.

Your probably thinking of a strap wrench, great for oil filters too.
 

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