Clear Green Pool Algae or Iron

[A046197]

I've been battling this clear to cloudy greenish pool for about 2 years thinking it was an algae problem. SLAMing about every 2-3 months with some clearing but then it comes back. I have staining of the pool steps and liner and tried ascorbic acid on stains and they cleared right up. Im thinking that the iron is coming in and out of solution and that is what is causing green water as well as a brownish film on the liner surface as seen in pictures. I plan to do the ascorbic acid treatment as described on TFP but just wanted to see if anyone else might weigh in so I don't end up spending a ton of time and money going do the wrong path. Ive kept my water balanced per TFP app guidelines with chlorine levels at 10 ppm for the last 4 weeks after my last successful SLAM.

 

[Bperry]

View attachment 531312View attachment 531313View attachment 531314View attachment 531315I've been battling this clear to cloudy greenish pool for about 2 years thinking it was an algae problem. SLAMing about every 2-3 months with some clearing but then it comes back. I have staining of the pool steps and liner and tried ascorbic acid on stains and they cleared right up. Im thinking that the iron is coming in and out of solution and that is what is causing green water as well as a brownish film on the liner surface as seen in pictures. I plan to do the ascorbic acid treatment as described on TFP but just wanted to see if anyone else might weigh in so I don't end up spending a ton of time and money going do the wrong path. Ive kept my water balanced per TFP app guidelines with chlorine levels at 10 ppm for the last 4 weeks after my last successful SLAM.

Your chlorine isn’t high at 10 if your CYA has been 70 ppm for long. Did you pass all three exit criteria when you did the slam process? And you were maintaining your chlorine level at 28 ppm?

 

[A046197]

Yes. It seems to be a never ending issue. I’ve read about the mustard algae and iron issues. Just trying to come up with the best approach since I’ve tried SLAM process multiple times in the past year.

 

[Mdragger88]

If you’re brushing it away it’s algae.
Have you done an Overnight Chlorine Loss Test?
This will tell you if it’s organic.
If you fail the oclt Do the SLAM Process
Until :
CC is 0.5 or lower;
You pass an Overnight Chlorine Loss Test
AND
The water is clear.
(Crystal Clear w/no recurring algae dead or alive)

While at slam level you can try using some polyfill in the skimmers & see what you catch. This is your best bet for actually removing the iron.

If you’ve got iron in your fill water, use Polyfill to remove it

EDIT: Found out this method only works if your iron is oxidized already, meaning it’s got a dull or bright green tint to the water, or a nasty brown tint. If you know you have iron in your fill water, but it isn’t oxidized yet, bring your pool to shock level and it’ll turn the telltale green...

www.google.com

After slam you would then do the AA treatment for stains that remain.
How did the iron get in the pool?

 

[A046197]

Good question? City water not well. The steps have been stained since we moved in 2 years ago. I rubbed a vit C tab on them and it disappears. Same when done to vinyl liner that is stained brown. I’ll try the OCLT tonight and see where it lands. Maybe it’s a combination of both algae and iron.

 

[A046197]

Overnight chlorine loss was 0. Should I still SLAM?

 

[duraleigh]

That's algae brushing up from your pool floor. Regardless of anything else, you have algae in your pool and need to SLAM the pool to get rid of it.

The entire pool floor and walls need to be brushed and the commence the SLAM. If you do it correctly, you pool will be clear.

Once you finish the SLAM correctly, you can address other issues but you have to get the algae out of your pool first.

 

[A046197]

Thanks just needed a nudge to SLAM again. Getting tired of SLAMing.

 

[Bperry]

Thanks just needed a nudge to SLAM again. Getting tired of SLAMing.

If you’re having to SLAM multiple times, then something isn’t right. You may be ending it too soon or not maintaining enough chlorine after it’s done. So do yourself a favor and really check those two possibilities. SLAM’ing is no fun.

 

[Mdragger88]

Repeat slams generally have a reason like the ones Bperry mentioned or you’re missing some nooks & crannies- be sure to do all the things
*Check & scrub every nook & cranny where algae may hide {light niches, steps (inside & out), drain covers, ladder handrails, skimmer throats/weirs, abandoned lines, autofill, overflow drains, seam flaps, etc.}
*If water can go there, algae can thrive there.
*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)
*Backwash/clean filter when pressure rises 25%over clean pressure.

 

[duraleigh]

Getting tired of SLAMing.

I hear you. The need to SLAM more than once is normally not following the procedure perfectly.

Make sure you meet the three criteria that must be met before you stop the SLAM. Then, make sure you keep adequate levels of chlorine constantly in your pool to keep algae away.

 

[A046197]

Hopefully this is the final SLAM for a while!! I think I got it right this time. This is the clearest in 2 years of owning the pool. Thanks for the confirmation.

 

[JJ_Tex]

Did you pass the OCLT and CC tests as well? Mind posting your most recent test results and telling us your post SLAM plan for chlorine?

Hopefully we can make sure this is your final SLAM ever.