Is this scale buildup, algae, or both?

[cferraro85]

This is my first post on the site, but I do want to thank everyone for their input to the forums. You really have helped this first time pool owner greatly.

I bought this house last yr and the previous owner had a pool service that had the inline chlorine feeder maxed out year round. MY CYA was over 120 when I bought the house and Calcium was through the roof. I have since then got the chemistry inline and have been working on clearing pool surface stains since then. I use the chlorinator minmally and I chlorate with liquid chlorine (mostly) and powdered shock occasionally. My chemistry is below.

Using K2006 test kit

PH 7.5
FC 4
TA 100
CH 270
CYA 50
Current Temp 86

20K gallon pool with spa and spillover. I run the pump 8-10 hrs in the florida summer. I replaced the propane Hayward heater last year after the flame tubes rotted out.


The pool water is clear however I do battle with algae and high phosphates regularly. I feel like weekly I am brushing green algae off the bottom of the pool with a SS brush. If i brush hard enough I can get some of the brown streaks/scale to come off of the black pearl pebbletec finish. I have used Jacks Magic iron and cobalt remover per instructions with no success. I have tried the vitamin C tablet trick but did not notice much difference. Finally i dried sprinkling some dry acid on one of the pool steps and it seemed to take some of the brown away. I left it on there for only 5 minutes before brushing it off.

My question: Is this calcium scale or some kind of hard algae that is causing these streaks in my pool? Is an acid wash or Jacks magic Copper and Scale stuff recommended? Any other recommendations?

Attached are some pictures of my situation.

 

[YippeeSkippy]

You may have a combination of things going on. Are these test results from one of the recommended test kits or a pool store test (ugh!)?

My first comment is that your FC is too low for your CYA level. For 60 ppm CYA your bare minimum FC level is 5, ideal is 7 and shock level is 24. If you've been under dosing your chlorine you can certainly be harboring a bit of algae.

Your CH is a bit low also. I think you need to raise it up to somewhere between 250-350 (I always pick a number smack dab in the middle, say like 300). If I saw that white area on cement outside of the pool I would wonder about efflorescence but I'm not sure if that is what I'm seeing? Have you ever dabbed at it with a dilute MA solution?

 

[cferraro85]

I updated the chemistry info in the original post. Also to your point about the white stuff on the cement, that is just the lighting on the flagstone and mortar surround. Also the pool finish is 15yrs old.

I have read the algae and SLAM instructions. Where do I go from here? Mustard level shock for several days? Calcium Scale removal treatment?

 

[cferraro85]

Any other suggestions guys?

 

[Megsyperk]

If you are battling algae, I'd start with the SLAM. Then worry about everything else after you've passed the OCLT.


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[duraleigh]

Any other suggestions guys?

Yes, Do as Megsy suggests above. You must first manage your water chemistry. The scale is a completely seperate long-term issue and you should ignore it until you are able to keep your pool algae free. There is no need to battle phosphates. They are irrelevant.