SLAMing mustard algae

[ZESTR]

Started SLAMing lastnight, our mustard algae situation never seems to resolve for more than a few weeks... I have done this before... I am confused.
We brushed 2x yesterday.
Left pump on 24/7.
Woke up-- LONG ring of yellow in the shallow end---- like a 10' curve of yellow streak!
Tested-- only lost 1.5ppm overnight... isnt that confusing? To SEE algae growing but it's barely eating chlorine? ANd, i keep getting 0.0 CC.
My CYA reading (which was tough to get, I had to use the other CYA test thing to compare and fighure out my CYA-- I was still seeing the dot in all types of light/shade)... I got 40CYA-- when my husband got chlorine from Pinch a Penny yesterday he asked them to test CYA just to see what they got, they got 50. So-- should I use the 50, or 40?

Reading yesterday before we slammed:
FC= 5
CC= 0
ph= 7.4
alk- 80
Calc- 190
CYA= 40

I just signed up for Flickr so I can post a pic to show you the pool- hope it works:
Pool- June 2015 SLAM | Flickr - Photo Sharing!
Pool- June 2015 SLAM | Flickr - Photo Sharing!

Water seems to maybe be turning gray? But, at the same time-- was so surprised to wake up and see that huge 10 foot line of yellow in the shallow end (I scrubbed it before I thought to take a pic)...

Is it just par for the course? Keep scrubbing, keep going, and it'll be fine?

It is just weird to me that we are not losing much chlorine (I tested at 8:15, then again at 9:15 and we had lost none. Husband is cleaning filter, then we will put pump back on and keep testing...)---and that it;'s a steady 0 CC...

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To clarify-
-Even on a good day, I scrub the pool every single evening and we swim in it DAILY
-We have been gettin a lot of rain
-Currently, it is hard to see the drain-- so it is pretty cloudy

 

[Texas Splash]

Zestr, a couple things that caught my eye in your note above:
- You mentioned you SLAMmed, but unless there is more info it doesn't appear to have been a full SLAM. Why? A SLAM takes more than one day. Also, to complete a SLAM, you must pass 3 criteria which has not happened. Your CC is still over .5 ppm, and you're losing more than 1 ppm of FC overnight. Also, if your CYA is truly 40, the minimum FC for a SLAM would be 16, and you're way below that right now.

Speaking of your CYA, I was a bit confused by the explanation above as to whether or not it was accurate. If you still see the dot, it's probably lower than you think. We never place much faith in any store testing.

If it were me, I would use the Taylor K-2006 to confirm your CYA and adjust your FC level to the "SLAM" FC level based on that CYA. Make sure you refer to the Chlorine/CYA chart (link below). Then keep it there until you pass all 3 SLAM criteria. Doing those things, you will complete the SLAM. Let us know if you have any other questions.

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Note - the Poolmath calculator shows a Mustard Algae FC SLAM level of 24.

 

[ZESTR]

Hi!
1. I stated above my CC is ZERO-- so it is not over .5
2. Mike from here--TFP--helped me test the CYA with that special CYA test that you do that shows 50ppm, then you restest to see your--- and I got 40. I've tested my CYA 10x in the last month an went through it all on the forum
3. No-- I said those were my numbers before SLAM--- then I SLAMd it and this morning it was 18.5... 5 hrs later it is still 18.5 FC, but going to add more to SLAM, need to go back to pool store for more chlorine

Going to keep plugging along

 

[Texas Splash]

Zestr, I stand corrected. Not sure what I was thinking/reading about the cc being .5. You clearly showed "0". That's good. From your narrative above I didn't realize you had someone's help (Mike) to help confirm CYA, I only saw your test and the Pinch a Penny visit. So if your pool is holding its FC that well, and your CC is zero, it's possible your pool is trying to filter-out the dead algae following the SLAM. That can take another day or two. You certainly can plug along, maintain the FC one more evening and validate those readings (OCLT) tomorrow. If you don't see an improvement in the water clarity, let us know. There may be some questions about your filtration to address to help resolve your problem. Have a good evening.

Zestr, web troubles prevent me from replying directly to your thread, but after re-reading your post, I wanted to make sure you understood something based on your concern about the yellow ring with low FC loss. First - Yes, you can have an algae issue even if there is no CC showing. So don’t let that fool you. It’s only one method to judge water conditions. Also, even though your FC loss was only 1.5 overnight, it is still a loss that exceeds the SLAM requirements of 1 ppm. So based on the cloudy water and FC loss exceeding 1 ppm overnight, you would be best advised to continue your SLAM. Keep it at 16 based on a CYA of 40 until you pass your SLAM, then go up to the Mustard Algae shock level of 24.

As you may already know, a SLAM can go as quick as 2-3 days, or can take a week or two depending upon the severity of the algae and consistency of the FC level. So stick with it and “maintain”.

Correction - Follow the normal shock of 16 until you pass the SLAM, then do the Mustard Algae FC of 24 as outlined in this link: Pool School - Mustard Algae

 

[ouachita]

In addition, the Mustard Algae FC SLAM level for your CYA is 24. Your second post stated you were at about 18.5 or so. So based on the cloudy water and FC loss exceeding 1 ppm overnight, you would be best advised to continue your SLAM. But you must keep it over 24 based on a CYA of 40.
”.

I was fixing to start a thread but will ask here since we are talking mustard algae. I was under the impression that for mustard you slammed at normal shock levels and when that passed all three tests you raised FC to mustard shock level and maintained that for 24 hours. I didn't think that you slammed at mustard algae shock level the whole time. Could someone please clarify this? I've seen a couple of posts lately where people say to do the whole slam at mustard levels.

Pool School - Mustard Algae This is where I read to slam normally first.

 

[Texas Splash]

Ouachita, THANK YOU for reminding me. You are correct! Here' is the link: Pool School - Mustard Algae

Too many posts on my brain today.

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Initial post edited above.

 

[chem geek]

With yellow/mustard algae you have to kill it everywhere or it can come back. That means behind light niches, under removable ladders, in cleaning poles, etc. If it gets frequently reintroduced then one can consider last-resort methods of remediation: 1) elevated minimum FC/CYA ratio of 15%, but that will use more chlorine, 2) use of a phosphate remover to get phosphates at or below 100 ppb but that can be expensive, 3) use of an ongoing algaecide though most are not as effective against yellow/mustard algae (not sure of Polyquat 60 would be sufficient; copper will work, but has side effects of staining plaster surfaces and turning blonde hair greenish).