algae maybe

[lkalred]

I have read that it is possible to get algae even though the CC is 0, you can pass the OCLT, and the water is clear. I have several light green spots on the pool plaster that are slowly becoming more prominent. I have been very careful to maintain the FC at 6-8 with a CYA of 40-50 with daily testing. SLAM is the next logical step. Guess I am surprised that some species of algae shows up anyway. I am brushing the pool surfaces regularly. These stains are quite difficult to remove, if at all, with vigorous brushing.
Is it possible to have iron stains that resemble algae? Since this pool is over twenty years old and my guardianship has been for less than one year, I don't know the history of what this pool has been subjected to.
Is this really algae?


Current levels:

FC-6
CC-0
ph-7.2
TA-50
CH-350
CYA-40

Thanks


Keith

 

[Donldson]

Any chance we can get some pictures? I don't know how likely it is that it could be algae, and if they don't brush off I am tempted to say they aren't, but a few pictures could sure help get you some more specific answers.

 

[Butterfly]

If it is green Edit: [s:17vrp5y0]and you can brush it off[/s:17vrp5y0], it sounds like algae.

Where are the stains in your pool? Can you post a pic?

What type of brush are you using? Nylon, combo, etc.?

I suggest you look in all the nooks and crannies. Do you have any underwater light niches? If yes, then pull them out, clean them and let them be exposed to higher FC. Brush/clean ladders, steps, skimmers and any thing that could hide algae.

 

[lkalred]

Hey everybody,

Tried to take pictures of what's going on in pool, but the light stains did not show. Regardless, the next day the stains weren't light and brushing stirred large green clouds. SLAM initiated at 2200, 7/24. Since my CYA level is between 40 and 50, brought FC up to 20 and have held it there. All day yesterday the FC was down significantly every time I would test. Last night I lost 2.5ppm, but, and this is where I'm at a loss, the CC level has remained has remained at 0-.5 the whole time.
My question is if chlorine is obviously being consumed, shouldn't there be a spike in the chloramines as well and how is it possible that the CC has remained between 0-.5 for weeks now if algae was building in the pool? Why wasn't a FC level between 4-8, maintained mostly ~8, enough to prevent algae? We have not had any more storms. The temp. has not been excessively high. Have actually noted a decrease in organic material being blown into pool and needing to be vacuumed out. The water has been crystal clear the whole time.
Please forgive all the newbie questions. Have been around long enough to know what to do but don't know the whys yet.

On a side note, have noticed that the scaling present in my pool has lightened some in response to neg. CSI being kept at ~-.6. Will keep at it.

Thanks TFP!!!

Todays testing:

FC-18.5 (added enough 10% to bring back to 20)
CC-0
other levels are from 24th, prior to SLAM
ph-7.1
TA-50
CH-350
CYA-40
CSI:-0.55

Thanks


Keith

 

[Butterfly]

What type of brush are you using? Nylon, combo, etc.?

I suggest you look in all the nooks and crannies. Do you have any underwater light niches? If yes, then pull them out, clean them and let them be exposed to higher FC. Brush/clean ladders, steps, skimmers and any thing that could hide algae.

 

[lkalred]

My question is if chlorine is obviously being consumed, shouldn't there be a spike in the chloramines

 

[lkalred]

And yes, I do have an underwater light. But, I don't have any idea about how to open it up. Don't want to pull it out and then not be able to get it back in or subject the water I'm in to 110AC. Woudn't be like the butter knife in the socket thing that we all did as children, where I could immediately disengage. And even 110 can kill, with prolonged exposure.
I'm beginning to understand just how insidious and stubborn algae can be.

 

[msgtdan]

Combined chlorine (chloramine, dichloramine, and nitrogen trichloride) primarily results from Free Chlorine (aka hypochlorous acid) oxidizing nitrogen based componds, such as urine/urea) ammonia, sweat, etc. If all you are doing is killing algae and not oxidizing the above, it's very possible you won't ever see CC show up before, during, or after the SLAM process.

This came from here http://www.troublefreepool.com/no-cc-reading-t66603.html

Here's a thread of what can be behind the light http://www.troublefreepool.com/think-i-may-have-found-my-fc-demand-issue-t65957.html

I don't think most are difficult to remove, but since I don't have one I can't help with that. Someone I'm sure will though.

 

[lkalred]

Thanks a lot MSGTDAN!!

YOU DA MAN DAN!!!

The kernels of wisdom to be found here re: taking care of a pool are just amazing and just what I need.

Now, I'm not relishing the thought of pulling the light fixture but I'm sure it needs doing and this will give me some encouragement to 'just go do it'. There's nowhere else that I can't get to easily, so this should reduce my FC demand.

 

[chem geek]

My question is if chlorine is obviously being consumed, shouldn't there be a spike in the chloramines as well and how is it possible that the CC has remained between 0-.5 for weeks now if algae was building in the pool? Why wasn't a FC level between 4-8, maintained mostly ~8, enough to prevent algae?

Chlorine consumption does not necessarily lead to CC because the reactions can be local (i.e. near the algae) and continue on to end products that don't register as CC, such as carbon dioxide and nitrogen gas and water (same products as found when "burning" organics).

I'm not so sure that something that is green and sticking so hard to the pool surface is algae. Usually if it sticks and is algae then it's black algae, not green. Green algae clumps but isn't that hard to brush off. Yellow/mustard algae is even easier to move around and is dust-like.

Anyway, the OCLT loss may indicate something lurking somewhere so it will be interesting to see what is behind the light niche. Also, you may consider improving the circulation of water in the area where you found the algae -- sounds like your bottom circulation is poor.

 

[danacc]

And yes, I do have an underwater light. But, I don't have any idea about how to open it up. Don't want to pull it out and then not be able to get it back in or subject the water I'm in to 110AC. Woudn't be like the butter knife in the socket thing that we all did as children, where I could immediately disengage. And even 110 can kill, with prolonged exposure.
I'm beginning to understand just how insidious and stubborn algae can be.

Your fear of being in electrified water is a healthy one. Find the breaker for your pool light and flip it off before touching anything to remove the light from the niche. Right after flipping the breaker off, try turning on the light to make sure it doesn't have power, and then put the light switch in the off position. Leave the breaker flipped off and the light turned off until after you clean the niche and put everything back together again.