Mustard Algae & About to Start Vacation

[doc19]

Hi, everyone. I have been battling some mustard algae for the last several days and although it is better than it was, it is not cleared up yet. I'm concerned because we are about to leave for vacation in 3 days and will be gone for 10 days. We do have a salt water generator, so I can keep that turned up higher than usual, but will be unable to test and add supplemental bleach as necessary. I would greatly appreciate any tips or insight that you have to offer.

FC - 12
CC - 0
pH - 7.7
TA - 60
CYA - 30
CH - 47
Salt - 3400

Is there anything specific that you would do like adding chlorine pucks as a supplement? Do you think I should add more salt to the pool before we leave?

Edited to add: If I'm running the robot several times a day (2 hour cycle each time covering bottom and sides), should I still be brushing 2-3 times a day?

Thank you!

 

[Rocket J Squirrel]

Your CYA is very low for a saltwater pool. It should be 60-90. Raising it will at least help your FC last longer. With FC at 12, go ahead and raise it to 90.

See ABC's of Pool Water Chemistry

The Free Chlorine and Cyanuric Acid Relationship

Managing your cyanuric acid and Free Chlorine levels is key to stabilizing your pool. Learn how these two items affect each other.

www.troublefreepool.com

 

[HermanTX]

Your CYA is very low for a saltwater pool. It should be 60-90. Raising it will at least help your FC last longer. With FC at 12, go ahead and raise it to 90.

See ABC's of Pool Water Chemistry

The Free Chlorine and Cyanuric Acid Relationship

Managing your cyanuric acid and Free Chlorine levels is key to stabilizing your pool. Learn how these two items affect each other.

www.troublefreepool.com

The OP should not raise CYA until algae is clear.
But that brings the question- is this something you have time to do. it may take a week or so depending on the starting condition to clear algae.
How do you know it is mustard algae.
Did you follow the
SLAM Process

 

[Rocket J Squirrel]

Indeed, the CYA should be low for the SLAM, but it doesn't sound like that's going to happen soon. A partial drain & fill after vacation will help prepare for SLAM.

 

[doc19]

I followed the SLAM process starting 5 days ago, and a lot of progress has been made. I don't think it was terribly bad, but I accidentally let the salt get too low in the pool and FC dropped for a bit. I was increasing the SWG, but without enough salt, it couldn't raise chlorine levels. I have always followed the TFP guidelines since adding the pool 3 years ago and have never had a problem. I think I got too comfortable and the algae snuck right by me. I have since learned my lesson, and it is a bit of bad timing.

I'm attaching some pics of the water, which is crystal clear. I only see one line, but it is in a spot that is full sun all day. My pool really isn't in shade at all until the late afternoon. What I'm seeing is a perfect line that has settled in a seem. I have also noticed some dark spots in a few places, but they are hard and do not brush up. In one corner I can see 3 or 4. I have just noticed these today and now I'm wondering if it's possible that these are tiny tears and this could be vermiculite accumulating at the bottom of the pool. I noticed that a sharp piece of clear debris (biodegradable yard stake) had gotten caught in the robot last week and am worrying that it actually created tiny tears. I am seeing a small bit of sand (maybe 1/8 cup each time) in the robot on a semi-regular basis, and we do not live in a sandy area. The water level seems stable, however.

I'm quite perplexed and would love to hear any advice you have.

Also, @rocket - Why would I need to do a partial drain and fill? I thought my numbers were OK...am I missing something huge?

For the pics: The dots are in the top right corner of the first pic, the center of the screen in the second pic, and the line of accumulated mustard/sand/vermiculite is in the third pic.

 

[Mdragger88]

Do you have a sand filter?
Are you able to physically inspect the area?
You would be losing water if there was vermiculite getting in

 

[Mdragger88]

Its more plausible that the metal stake caused rust spots.
You can try crushing some vitamin c and putting it in a sock and rubbing/sitting it on the spots to see if they lighten.
Its a chemical reaction- if its too deep for you to reach you can attach it to your pool brush with a rubber band to get it down there.

Have you done an Oclt yet?

 

[Rocket J Squirrel]

Also, @rocket - Why would I need to do a partial drain and fill? I thought my numbers were OK...am I missing something huge?

Sorry, I was making assumptions based on incomplete information. Didn't know you had already slammed. Just ignore me.

 

[doc19]

I do have a sand filter, and it is only 3 years old. We have not changed the sand yet, but are planning to before next summer.

I don’t think it’s rust spots because the stake was biodegradable plastic. When I run across them, I can feel them with the brush, so I they are not completely flush. I need to dive in and check them out, but haven’t been able to since discovering them a few hours ago.

 

[Mdragger88]

I do have a sand filter, and it is only 3 years old. We have not changed the sand yet, but are planning to before next summer.

I don’t think it’s rust spots because the stake was biodegradable plastic. When I run across them, I can feel them with the brush, so I they are not completely flush. I need to dive in and check them out, but haven’t been able to since discovering them a few hours ago.

Keep us posted!
They do sell decent patch kits at lowes if needed.
About the slam part - if you can have it at slam level when you leave, float some pucks & set your swcg to maintain daily losses while you’re away you shouldn’t loose too much ground.
Here’s what your swcg can do in your pool if on 100% 24/7
Note* the average algae free pool can have losses of 4/5ppm in the summer in the south with a cya of 60-80. Your swcg is undersized for your pool volume & you may need supplemental fc additions during parts of the season.

 

[Mdragger88]

Ideally you would complete slam before leaving. Then still do as I mentioned above.

 

[HermanTX]

I am in full agreement with @Mdragger88
Continue the SLAM for the days before your vacation. It is unlikely to be mustard algae - but there is something there.
Test your Salt and put that in proper range for your SWCG.
Keep your FC level at 12 ppm (CYA at 30ppm) and do a Overnight Chlorine Loss Test just to see the current status.
Let us know results and discuss any last questions the day before you leave.

Do you have anyone that can add liquid chlorine while you are away?