mustard algae...pool store no help

tamtidwell

New member
Aug 22, 2013
4
13k gal AG with a sand filter (hp not known right now)
FC .5ppm
CC .0
TC .5
PH 7.5
Alkalinity 70
CYA 10

I have been fighting mustard algae for 2 weeks. I have found a lot of helpful info here, but got a question. I'm going to SLAM the pool to get rid of algae ,pool place keeps selling me algacide which is not helping so time to try something else. We have been vacuuming to waste but algae keeps coming back. The pool place keeps telling me not to add stabilizer yet cause my levels are not right but I can't get my chlorine levels up cause the algae is eating it up. The chart for SLAMing on here starts at 20CYA but my CYA levels are only at 10. Should I go ahead and add stabilizer before starting the SLAMing and if so how long do I wait before bringing my FC levels up to shock?
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
43,260
Tucson, AZ
:wave: Welcome to TFP!!!

We generally suggest getting the CYA to around 20-30ppm before SLAMing ... reason being, you can not accurately test below that. If you leave the CYA low, then you will be losing a lot of your chlorine to the sun during the day.

Follow the SLAM process and the pool will clear up. After completing the SLAM, then read the article about mustard algae in Pool School ... BTW, most people that come here saying they have mustard algae, do not in fact have it.

Continue to brush and vacuum and backwash your filter when the pressure rises 20-25% over the clean pressure.

BTW, how are you planning to measure the elevated FC levels? You need one of the Recommended Test Kits to SLAM correctly. And you need to stop listening to the pool store. ;)
 

257WbyMag

TFP Expert
LifeTime Supporter
Feb 23, 2008
5,061
Denton, TX
Welcome to TFP!

If those are the pool store numbers, please order a good test kit from tftestkits.net. You'll need it to eliminate the algae from your pool.

It is good to have a baseline CYA of 30 in your pool when shocking. It keeps you from losing your FC to the sun. As for vacuuming, you will never be able to vacuum all of the algae out. Best to cure things chemically first and then you can send the dead algae to waste.

Algaecide, as you have figured out, won't help your problem. Don't buy anymore. Order a test kit and dump a jug of bleach into the pool each night with the pump running. Once you get your kit, test things and post the numbers. Then we will get you fixed up. :goodjob:
 

tamtidwell

New member
Aug 22, 2013
4
I have read the sections on mustard algae and wondered if that's what I had....but a test at the pool store said that mustard algae was present so that's all I can go by until I get the levels up and see if it goes away. It's a very frustrating process
 

duraleigh

Admin
Mod Squad
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In The Industry
Apr 1, 2007
32,859
Sebring, Florida
do I need to go ahead and add a stabilizer to bring my CYA up to 30?
Yes. You'll be ahead of the game.

MOST IMPORTANT - don't overlook that jug of Clorox each evening as 257 suggests.....that's almost mandatory if you want to prevent an algae bloom.

Post up your test results as soon as your kit get in. Thousands of people here to help. :wave:
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
43,260
Tucson, AZ
They can not test for a specific type of mustard algae.

I hesitate to suggest you raise the CYA too much as they are just so bad at testing it. You could at 10-20ppm more and then be able to test it after a week when you get your kit.

You could also be trying to maintain the FC around 8-10ppm while you wait. If you have a DPD or OTO test, use half distilled water with pool water and then double the reading.
 

tamtidwell

New member
Aug 22, 2013
4
How long do my kids have to stay out of the pool with the algae and SLAMing process? Got my kit from Leslie's Pool Supply, stabilizer added, my water is looking much better after the first several gallons of bleach and my stabilizer is up to around 25 and my FC is at 20 so I won't add more bleach until the numbers come down a bit (per chart). However my kids are driving me crazy to swim and I'm not sure if it's safe.
 

ping

TFP Expert
LifeTime Supporter
Jun 24, 2011
3,018
Long Beach, CA
We say it is safe to swim in water that has a FC level at SLAM level or lower. Your pool is well above the SLAM level needed, so I would advise you to not let the kids go swimming. :grrrr:
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
43,260
Tucson, AZ
Which kit did you buy? The K2005 DPD or the K2006 FAS-DPD? Very rare to find the correct one, the FAS-DPD at Leslie's so I hope you got lucky.