Black Algae Starting - Please Help!

[MeowMeow724]

Hello.... the perfect storm has occurred and I am now realizing I am starting to have a black algae problem in my pool.

I started seeing some black colored build up on some tile grout lines and finally took one chunk off and smeared it onto a towel, which turned green.

I noticed a couple of small spots on the wall that I scrubbed and some came off but it is still there.. now there is a third spot and what I think are a ton of tiny ones likely throughout a lot of the pool.

This started because well, life happened... but I decided to use some Leslie's Pool Supply Scale and Stain Remover because my plaster was looking icky and I believe it was scale because I have a tough time keeping my pH in check with the salt cell though I do try really hard to. Then I was having trouble getting my salt cell back in order and it was raining buckets every day, so I was chlorinating with liquid chlorine as much as possible but obviously not well enough. It is my fault, I was neglectful.

Little did I know, now I have high phosphates and have had low (and many times 0) chlorine until recently when I finally got the salt cell back up and running properly. Now I know the implications of that... and just bought some phosphate remover which I have not put in the pool until I get the filters swapped out this weekend.

I had a water test done earlier this week at the pool store when I went to get some supplies (I don't rely on their tests, but bring a sample with me sometimes when I go) and their test had to have been wrong. They tested 120 alkalinity, 3 chlorine, which my tests are consistently 90 alkalinity and very different chlorine. So I do not trust them. But they tested my phosphates at 2,500 ppb and I have no way to confirm but I do believe they are very high as I used a whole bottle of the scale and stain remover.

What should I do here? I feel like I am seeing more black spots pop up the last few days, though very small. If there are a ton of small spots all over, how would I target them?
-Most of the tile grout has green algae on the lines, but I do not know if that is the black algae or just regular algae.
-There are about 4 small spots I now see, one popped up on the shallow end bench today.
-Most of the plaster has discolorations all over it (which I don't believe is algae), which some have been there but I do notice way more after the scale and stain remover so I am totally regretting using it at this point.. I didn't do anything good.
-Our robot pool vacuum has a ton of black spots covering the spring filter, which it has for a while. I am now wondering if that is also the algae. I spray it with the jet setting on the hose and nothing comes off.
-Overall the plaster looks awful and I have been thinking it was metal staining, so I bought a filter for when I need to add water and use Jack's Magic pretty consistently now (which I used to then also fell off that wagon before, as well).
-I have a stainless steel brush I can use to scrub as good as I can.
-I have a second set of filters that I will swap out this weekend, but please let me know if there is a specific sequence I need to do things in.
-I have phosphate remove ready to be used.

We also have a HUGE oak tree that is dropping acorns like mad right now, so keeping it free of those during any point of the day is nearly impossible.

Here is today's test result:
FC: 16 (but the new bottle of R-0871 I got from TFP is honestly terrible and double drops before I can swirl so this might be a little off...)
CC: 1.5 (I have only ever had this be as high as .5 so his scares me a bit)
pH: 8
ALK: 90
CH: 300
CYA: 50
Salt: 3200
Temp: 68

Please help before it gets out of control I am so mad at myself!

Thank you!

 

[Texas Splash]

You can ignore the phosphate concerns and go right into the SLAM Process. With a CYA of 50, your SLAM FC level should be 20. Follow that SLAM Process carefully and consistently and you'll achieve success. If you have questions about the process let us know.

Black Algae

This guide provides a step by step procedure for eliminating black algae in your concrete or gunite pool. Read full post here.

www.troublefreepool.com

 

[MeowMeow724]

You can ignore the phosphate concerns and go right into the SLAM Process. With a CYA of 50, your SLAM FC level should be 20. Follow that SLAM Process carefully and consistently and you'll achieve success. If you have questions about the process let us know.

Black Algae

This guide provides a step by step procedure for eliminating black algae in your concrete or gunite pool. Read full post here.

www.troublefreepool.com

Thanks!
I'll have to go get a bunch of liquid chlorine. I think I only have 1 gallon and didn't refill my jugs since the SwG is running again.

If I go above the recommend FC level at any point, is that going to mess it up?

Also, with my current FC being so high (I was trying to kill the algae!) I suppose I need to bring that back down to ensure my pH test is accurate so I know I'm starting at 7.2-7.5?


Do I need to maintain the pH to the level of 7.2-7.5 the whole time I'm SLAMing?

With the water being colder, having the lower pH tells me my CSI is going to be high scaling potential. (High negative CSI)
My plaster already looks like Crud so I guess it's no biggie at this point.

I assume I need to brush pretty aggressively?

And, do I need to change out my cartridge filter before I start or should I wait?
It needs to be cleaned anyways. My pressure gauge is reading fine but the pressure isn't what it should be so it's ready for a cleaning.

Do I need to change the filter/clean the filter during the process?

And when it says to vacuum, is my robot sufficient or do I need to use the manual vacuum - which I really suck at using?


Thank you!

 

[Mdragger88]

What was your ph before you raised fc above 10ppm? If it was 7.2-7.5 you can just proceed with SLAM Process.
Your logs have a large gap. You can’t reliably test ph above 10ppm fc so you will let it ride & only test fc & cc. Thus the reason to adjust it before beginning. Your resulting csi is not an issue so long as it is rectified after slam is completed. Systemically hanging out in non recommended csi territory is what causes issues.
The increased cc’s could partially be caused by leftover stain & scale remover- they should dissipate as you carry on.
Going above Slam level for your cya just wastes chlorine & risks damage to swimmers & equipment. Maintaining is the secret sauce. SLAM means Shock Level And Maintain.
For a successful SLAM Process
you need to continue to MAINTAIN Slam level fc for your cya as often as possible until you meet ALL 3 end of slam criteria-

You are done when:

CC is 0.5 or lower;
You pass an Overnight Chlorine Loss Test
AND
the water is clear.
(Crystal Clear w/no algae dead or alive)

*Check & scrub every nook & cranny where algae may hide (light niches, steps, drain covers, ladder handrails, skimmer throats/weirs, etc.)
*Run slam level water through all water features & lines for at least a couple hours a day during the SLAM Process.
*Brush & or vac daily (this breaks up biofilms that algae uses to protect itself from chlorine) using a robot is fine
*Backwash/clean filter when pressure rises 25%over clean pressure. (You should do this even when you aren’t slamming)
Aggressive brushing is definitely important for black algae. Check out the black algae article Pat posted for extra tips on the subject.

 

[MeowMeow724]

What was your ph before you raised fc above 10ppm? If it was 7.2-7.5 you can just proceed with SLAM Process.
Your logs have a large gap. You can’t reliably test ph above 10ppm fc so you will let it ride & only test fc & cc. Thus the reason to adjust it before beginning. Your resulting csi is not an issue so long as it is rectified after slam is completed. Systemically hanging out in non recommended csi territory is what causes issues.
The increased cc’s could partially be caused by leftover stain & scale remover- they should dissipate as you carry on.
Going above Slam level for your cya just wastes chlorine & risks damage to swimmers & equipment. Maintaining is the secret sauce. SLAM means Shock Level And Maintain.
For a successful SLAM Process
you need to continue to MAINTAIN Slam level fc for your cya as often as possible until you meet ALL 3 end of slam criteria-

You are done when:

CC is 0.5 or lower;
You pass an Overnight Chlorine Loss Test
AND
the water is clear.
(Crystal Clear w/no algae dead or alive)

*Check & scrub every nook & cranny where algae may hide (light niches, steps, drain covers, ladder handrails, skimmer throats/weirs, etc.)
*Run slam level water through all water features & lines for at least a couple hours a day during the SLAM Process.
*Brush & or vac daily (this breaks up biofilms that algae uses to protect itself from chlorine) using a robot is fine
*Backwash/clean filter when pressure rises 25%over clean pressure. (You should do this even when you aren’t slamming)
Aggressive brushing is definitely important for black algae. Check out the black algae article Pat posted for extra tips on the subject.

Thanks!
My FC was at 10, 4 days ago and my pH was 7.6.

My log shows 8.0 when it was 10 FC, but I added acid right after that test and didn't log the re-test.
I've been bad with my logs. I do the testing and adjustments, just haven't been logging them consistently. I also didn't renew the app for a while so I didn't have the ability to log in PoolMath for a while earlier this year.

However, given that my SWG has been running at a very high % (currently at 80%) so have to believe my pH is very high right now as I haven't added any more acid in 3 days, counting today and it would usually climb a few points overnight this way.
I am a bit uncomfortable starting SLAM without adding some acid to lower pH first. I know I will need to maintain chlorine by liquid so the SWG will be off so it shouldn't raise too fast once I do, but it still concerns me. It will probably hit the 9.0 range if I don't and I don't want to cause other problems. Will that mess up the SLAM?

 

[Texas Splash]

If your FC is at about 10, it's fine to test and adjust your pH to around 7.2-7.4. Good luck!

 

[mknauss]

Your pH rise and SWCG use is not related. SWCG use does not raise your pH. Aeration and/or chemical additions raise your pH.

 

[Bperry]

Thanks!
My FC was at 10, 4 days ago and my pH was 7.6.

My log shows 8.0 when it was 10 FC, but I added acid right after that test and didn't log the re-test.
I've been bad with my logs. I do the testing and adjustments, just haven't been logging them consistently. I also didn't renew the app for a while so I didn't have the ability to log in PoolMath for a while earlier this year.

However, given that my SWG has been running at a very high % (currently at 80%) so have to believe my pH is very high right now as I haven't added any more acid in 3 days, counting today and it would usually climb a few points overnight this way.
I am a bit uncomfortable starting SLAM without adding some acid to lower pH first. I know I will need to maintain chlorine by liquid so the SWG will be off so it shouldn't raise too fast once I do, but it still concerns me. It will probably hit the 9.0 range if I don't and I don't want to cause other problems. Will that mess up the SLAM?

The SWG doesn’t raise pH very much at all, but high TA will.

 

[MeowMeow724]

Ohhh! Interesting.
That's the opposite of what I've always heard and feel like I have experienced.
I notice a vast difference when I use my SWG or have it off. The pH rises FAST when it is on and I have to use acid a lot when it is.
When I just use liquid chlorine it rises very, very slowly by comparison.

Another thing ...
This morning I did some spot brushing and I'm noticing a lot of browning areas in the pool. Brushing *I think* lightened up some areas but others are not changing at all.
Could that be the black algae forming? Or other algae forming?

It's very hard to scrub those very well and all over because I simply don't have the strength or enough energy to do it for long.

I tested chorine this AM again, and it was around 11.5, but again, that dropper bottle is not good (please TFP, change it back to the old version!) So I have to go get a new bottle so I can accurately test Chlorine. I try hard but it keeps double dropping and I have no idea if I getting right sized drops for my testing.

if accurate, I lost a lot of chlorine since yesterday and had even bumped the SWG up.
does that mean it's fighting the algae since the chlorine is getting eaten up really fast?

 

[Bperry]

Ohhh! Interesting.
That's the opposite of what I've always heard and feel like I have experienced.
I notice a vast difference when I use my SWG or have it off. The pH rises FAST when it is on and I have to use acid a lot when it is.
When I just use liquid chlorine it rises very, very slowly by comparison.

Another thing ...
This morning I did some spot brushing and I'm noticing a lot of browning areas in the pool. Brushing *I think* lightened up some areas but others are not changing at all.
Could that be the black algae forming? Or other algae forming?

It's very hard to scrub those very well and all over because I simply don't have the strength or enough energy to do it for long.

I tested chorine this AM again, and it was around 11.5, but again, that dropper bottle is not good (please TFP, change it back to the old version!) So I have to go get a new bottle so I can accurately test Chlorine. I try hard but it keeps double dropping and I have no idea if I getting right sized drops for my testing.

if accurate, I lost a lot of chlorine since yesterday and had even bumped the SWG up.
does that mean it's fighting the algae since the chlorine is getting eaten up really fast?

If you lower the TA the pH won’t go up so fast. The 9lbs of baking soda you added last month is causing the pH to rise faster. Try letting it be at 60ppm next time.

You need more chlorine to get to 20ppm and keep it there as much as possible until it’s clear and you aren’t losing more than 1ppm overnight.

 

[Newdude]

I notice a vast difference when I use my SWG or have it off. The pH rises FAST when it is on and I have to use acid a lot when it is.

How high are your returns aimed ? The aeration caused by running the pump long enough to produce the days FC is the usual culprit. Of course, it's the SWGs fault and not the pump/returns.

You can try lowering the returns so they don't or barely break the surface.

 

[MeowMeow724]

How high are your returns aimed ? The aeration caused by running the pump long enough to produce the days FC is the usual culprit. Of course, it's the SWGs fault and not the pump/returns.

You can try lowering the returns so they don't or barely break the surface.

The returns don't break the surface at all. I learned about the aeration increasing pH early on so I made sure of that since I've always had a hard time controlling the pH.
I actually run my pump 24/7 on medium and low speed based on a schedule.


I raised the TA (and keep it higher) to keep my CSI in range. I'll have to try and find the ideal combo of other chemicals with TA at the lower range. However, I am surprised to hear I should get my TA down as low as 60. At one point I had it at 70 and I was told to bump it, and in order to keep my CSI in good range it was difficult to with TA at the lower range but I will give that a shot. Having to add as much acid as I do will drop it relatively soon anyhow.

thanks all for the tips and info!
I'll go bump my SWG now and go grab liquid chlorine tomorrow.

I also think I'm going to order the pool Whale brush. It's nylon but I think it'll still be able to put more pressure than I can.

 

[Newdude]

However, I am surprised to hear I should get my TA down as low as 60. At one point I had it at 70 and I was told to bump it, and in order to keep my CSI in good range

Sometimes plugging one hole makes 2 others leak.

It's specifically called trial and error.

also think I'm going to order the pool Whale brush

For all the products out there that don't live up to the hype, the Whale brush delivers and then some. I actually didn't like mine because it put such force on the wall it was difficult to brush. Maybe my tall leverage worked against me for once, I dunno. But that thing STICKS to the wall.

 

[MeowMeow724]

For all the products out there that don't live up to the hype, the Whale brush delivers and then some. I actually didn't like mine because it put such force on the wall it was difficult to brush. Maybe my tall leverage worked against me for once, I dunno. But that thing STICKS to the wall.

Well, I ordered it because that convinced me It's what I need 100% even though I'm skeptical because it's nylon on plaster.
I need more omph because I'm weak

 

[Mdragger88]

There are multiple factors that play into csi.
Play with the calculator a little to get a better understanding of how they work together. Aim for neutral to slightly negative.

Calcium Saturation Index (CSI)

How is CSI calculated? Very simple – use our PoolMath tool. To ensure long plaster life and save money, click here to learn more.

www.troublefreepool.com

You cya has been low for a swg pool in sunny florida- especially in the summer unless your pool is covered. After slam is complete you may want to up it a dab

 

[MeowMeow724]

Of course, now that I got the filters changed there is a small amount of air leaking out of the pressure relief valve on the filter, and a small drip coming from where the lid meets bottom.

I took it apart a second time and lubed it again but will do it once more and see if that solves it. If not I'm two steps back on trying to get the black algae cleared... And it'll probably get worse. It's probably not a good idea to keep the system running if I'm hearing air from the relief valve, right?

If I need a new o-ring I probably have to order it which will take who knows how long to arrive.

 

[Texas Splash]

It's probably not a good idea to keep the system running if I'm hearing air from the relief valve, right?

Not ideal, but if the leak is very small, like a drip every few seconds, you can limp along until you get it replaced. However keep in mind when you turn off the pump, air will get sucked "in" to that relief area and you may hear water moving around and the pump pot may empty.

 

[MeowMeow724]

I notice a small amount of water coming from the top, which is probably coming from the relief valve.
And a small amount dripping down from the side.

I did see a tiny slit in the o-ring upon second inspection so it's possible that's the culprit.

It's actually coming out the side pretty consistently. Maybe 2-3 seconds then there's a few drops, then 2-3 seconds there's a few drops.

 

[MeowMeow724]

Another pic.

 

[MeowMeow724]

We took everything apart again and put it back together. The o-ring is now showing some metal after cleaning it with a rag so I'm suspecting that's our culprit. And can find one locally.

It's dripping a little less now, and no air sounds from the relief valve but I'm going to keep it on low speed since it drops even less then.

Fun times!