CH Test clumpped up. Is this normal?

[aespinoza101]

I moved into a home with a pool. I moved in about a month ago and had issues with vacuum leaks at the plumbing and a leaking filter. Home warranty finally fixed those issues so now I’m I the process of vacuuming up the bottom with a Zodiac MX8 and cycling the pool water. I also started testing the water quality and seen something unusual when doing the CH test. I noticed the test sample clumped up. Is this something to be concerned about? See picture
A bit of history of the pool. About a week after moving in we experienced a bit of rain. Without a properly working pump system I was unable to cycle the water. A few days later I noticed black spots. I did the finger nail test and figured it to be black algae. I then toss in four bags of Power Powder from the local pool store, which seemed to stop further growth. The black alga remains and now with my newly arrived TF-100 test kit, I proceeded to test water quality to present to all of you for some advice and remedy of black algae. My concern at the moment is the clumping of the CH test sample. However, after showing you all my test results, it might reveal other issues. Can someone please advice what the clumping is?

Test Results
FC = 3.5
CC = 0.5
CYA = 55
TA = 160
CH = 300

 

[Patrick_B]

The clumping is the precipitation of minerals during the performance of the test. Don't be concerned with it as it isn't unheard of. I am curious about your pH since it isn't listed however. Can you please report back with that?

As for your Black, and other Alagae issues, it's simply a matter of consistent low Chlorine in the pool. No worries though, you can fix that going forward. With the new kit, and the information you'll find here we can help you get the pool right. I want to suggest first that you thoroughly review the ABCs in Pool School. The basics are crucial.

To be rid of further Algae outbreaks, and the Black Algae, you will need to perform a SLAM procedure on the pool. Before you begin, please let us know what the pH is. It needs to be correct before you begin. Let's do that for a start, and work from there. You can find the information I mentioned by clicking the links in my signature below.

 

[Richard320]

I don't know what the clumping is, but I've had it, too. It has nothing to do with algae.

I generally add some R-0012 first, and then proceed normally using the 10 ml sample. Check out Post #7

Your FC level is too low for your CYA level. You'll need to keep it above 5 to prevent further algae outbreaks, and even higher than that to get rid of the black algae spots. If you don't have a stainless steel brush already, you need to get one. Pool School - Black Algae

 

[aespinoza101]

Thanks for the replies.

Patrick_B, I found this post last night http://www.troublefreepool.com/threads/18390-Taylor-calcium-hardness-test-wierdness. Just as you said, due to mineral in the supply water.

Richard320,
Have read pool school multiple times and watched Youtube video of TF-100 test instructions.

pH results 7.8 maybe 8.0 but definitely lighter in color to 8.2.
FC = 3.5
CC = 0.5
CYA = 55
TA = 160
CH = 300

 

[aespinoza101]

Pool calculator suggests 7 gallons 3 quarts or 10 (96 oz) jugs to get SLAM my pool up to FC of 20 with a CYA level of 50. Is this correct?

 

[Richard320]

Pool calculator suggests 7 gallons 3 quarts or 10 (96 oz) jugs to get SLAM my pool up to FC of 20 with a CYA level of 50. Is this correct?

If your CYA is above 50 but bekow 60 -- you called it 55 -- Shock level is actually 22. I see it taking 9 jugs of standard 8.25% bleach.

However... according to the article on black algae that I linked earlier, you only need to "Maintain an FC level between the high end of the recommended “Normal” range and the Shock (SLAM) level according to your pool’s CYA level."

That puts your target somewhere between 9 and 22. Four 121 oz jugs of 8.25% bleach will bring you up from 3.5 to 11.5 FC. And then you'll likely need about a jug and a half a day to maintain it at that higher level.

 

[aespinoza101]

Should I bring TA down by reducing pH with muriatic acid before adding the bleach to shock level?

 

[Richard320]

Should I bring TA down by reducing pH with muriatic acid before adding the bleach to shock level?

Nope. Your CH is low enough that you're not in imminent danger of scaling, so all you need to do is maintain the pH in range and TA will come down naturally with each acid addition. Keep pH in range and FC on the high side and brush the spots a couple times a day.