Algae problem maybe

[CtP]

New pool owner here. We live in Mobile, Al. We have a 24,000 gal vinyl pool with a sand filter. Being a new pool guy I didn’t know all the essentials to maintain a pool and the Chlorine level dropped and we had algae. It’s been a couple weeks and Leslie pool store said we have mustard algae, simply by a description of brushing it to a plume in the morning and color. It seems to be throughout the pool and on diagonals into the deep end. Mistakenly I shocked with powder chlorine and added tabs to inline chlorinator ( understand now that’s a no no ) and the CYA level is now up. I’ll post some pics and see it that helps. I want to say it’s pollen since the FC level has been over 10ppm for weeks and it hasn’t improved, but then again maybe I didn’t shock it to a high enough FC level.
Should I pump it down, maybe during a vacuum to waste to clean the bottom and lower the CYA.
Any help is greatly appreciated
What do ya think?
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[Texas Splash]

Hello! If we were to assume the pool store test were close (which we usually don't rely upon), your CYA is one major issue. It's extremely hard to keep the pool properly sanitized when the CYA is over 100. First and foremost though, before you try to remedy the situation, I highly encourage your to get your own test kit. I recommend the TF-100 (link below) as it uses Taylor reagents but in larger capacities which is a better value. Until you can test the water on your own with accurate results, you may be adding chemical not warranted. Until you can get your own test kit, simply add one gallon of regular liquid bleach to your water each day. When you get the test kit, post a full set of numbers and we can advise you from there. We look forward to hearing from you again. Let us know if you have any more questions.

 

[Patrick_B]

Welcome to TFP!

You could have well over 100 Cya, but it's hard to know without your own testing. Often, it's higher than pool store testing but it's a guess. I would suggest getting your own kit to be sure, and begin a study of pool school. Re-read the ABCs, and ask all the questions you need to. Adding pucks or shock isn't bad on its own, but adding things without your own kit to test, then determine the need for, and results of additions will get you in trouble. No problem though, with a little knowledge and good test results you can like this out quite easily.

 

[CtP]

Thanks for the advise thus far. I'll get a kit on order and go from there. Is the idea to add bleach daily to keep the FC up in relation to the CYA?

Do the pictures look anything like mustard algae?

 

[Texas Splash]

Right now, the gallon per day is simply to keep things from getting too much worse. It won't remove all the algae. The pics looks like regular algae so far. Regardless though, the treatment for MA is the same as regular algae, with one exception at the end which we can address later when you get your kit. When you get your kit, you'll need to "SLAM" via the link below in my sig. So you should get familiar with that in advance.

Also, please add your pool info to your signature by going to the top of the TFP web page (just under the Pool School button) and select "SETTINGS". On the next page look to the left for a menu bar that says, “MY SETTINGS” and go to "EDIT SIGNATURE" to enter your pool and equipment info there. It will help us later.

One more suggestion - consider requesting the "speed stir". It makes mixing so much easier.

 

[duraleigh]

Do the pictures look anything like mustard algae?

No. Mustard typically grows in a thin film on the shady WALLS of your pool.....it doesn't settle into the steps.

 

[CtP]

TF-100 is on its and way, with speed stir. Been adding a gal of bleach each day. I'll post back with test results.
Thanks again TFP!

 

[Catanzaro]

Welcome to TFP and congratulations on the purchase of the TF-100 Test Kit. Hopefully you purchased the Speed-Stir.

So you become comfortable with testing, below are the videos for the TF-100 kit. Please follow the instructions on the laminated card.

https://www.youtube.com/channel/UCNFkPFCkt9Y_YYNAeLtUr1g

We suspect your CYA could be higher then 100, and it is recommended that you perform a "dilution CYA test". Mix 50% tap water and 50% pool water (shake well) and use this for your testing. Then multiply by 2. If your CYA test is 80, then your true CYA is 160. This should be your first test as the SLAM level to clear up your pool all is based on your CYA. Depending on your CYA level, we may recommend that you replace some water before starting the SLAM process. Please keep us posted!

 

[CtP]

Catanzaro,

Thanks for the advice. Speed stir is on its way as well.

Looking through the Pool School info, I didn't see any numbers for draining and refilling based on high CYA levels. If my test reveals high CYA levels anyone have an idea of how much water needs to be replaced?

thanks again!

 

[duraleigh]

If my test reveals high CYA levels anyone have an idea of how much water needs to be replaced?

It's a direct replacement. If your CYA is 100 and you would like 50, replace 50% of your water.

 

[tim5055]

It's a direct replacement. If your CYA is 100 and you would like 50, replace 50% of your water.

If you are math challenged like me Pool Math will make all your calculations for you.

 

[kimkats]

I would also be brushing your pool so it does not make stains or get too much worse. Brushing will get it up into the water for the bleach to grab it and start working on it!

Kim

 

[CtP]

Test kit came early!

CYA - 160 - used the 1/2 pool and 1/2 tap water method
FC - 21
CC -.5
PH - 7.2
TA - 130
CH - 125

Pool math says I need to replace 75% of the water. OUCH! Any advice for this with for a vinyl pool? Guess I need to start here and get my CYA levels good.

 

[tim5055]

Test kit came early!

CYA - 160 - used the 1/2 pool and 1/2 tap water method
FC - 21
CC -.5
PH - 7.2
TA - 130
CH - 125

Pool math says I need to replace 75% of the water. OUCH! Any advice for this with for a vinyl pool? Guess I need to start here and get my CYA levels good.

What is your fill water source, City water or well?

With a vinyl pool you want to always maintain at least a foot or two of water in the shallow end. Draining more than that can let the liner shift/float.

 

[Catanzaro]

OUCH! Any advice for this with for a vinyl pool?

.. For starters, no more pool store testing.

.. You will need to replace a minimum 50% of your water. This should bring your CYA low enough to actually start the SLAM process, and while SLAM is occurring, then you can replace the additional water needed to your comfortable level. If you are planning on closing the pool, a level of 60-70 could be acceptable as you could always lower your level in the spring and the CYA may drop during the winter months. For some reason, I always seem to loose 20 ppm during the winter.

.. Your TA is also probably high, but your PH is low. Usually a high TA has a higher PH. Did you wipe the dropper bottle while performing the TA test? This could lead a high false reading. The 3" tablets could have contributed to the lower PH as well.

Next year, you may find that your PH will have a tendency to drift upwards pretty quickly based on higher TA, so please keep an eye on PH and test daily, if needed. And as Tim mentions (Drain/Fill) and repeat process so the liner does not develop wrinkles, shifts or floats.

 

[CtP]

Water source is from the city, lake fed.

I did wipe the bottle with a damp paper towel between drops.

I have been using baking soda to raise PH. At the time I didn’t realize Borax was an option to raise PH without raising Alkilinity?

Guess I’ll start draining. I’ll take the CYA to the 60-70 and see what happens over the winter. We do plan to close the pool. Would you recommend filling to the normal level for the SLAM process then drain?


Thanks for the feedback!!

 

[tim5055]

I have been using baking soda to raise PH. At the time I didn’t realize Borax was an option to raise PH without raising Alkilinity?

Guess I’ll start g. I’ll take the CYA to the 60-70 and see what happens over the winter. We do plan to close the pool. Would you recommend filling to the normal level for the SLAM process then drain?


Thanks for the feedback!!

Baking soda is used to adjust TA, not pH.

If you are going to SLAM then you have to bring it to normal level so you have access to the skimmers and water circulation. You want the chlorine everywhere so it can find/kill all the bad stuff.

 

[CtP]

Baking soda is used to adjust TA, not pH.

If you are going to SLAM then you have to bring it to normal level so you have access to the skimmers and water circulation. You want the chlorine everywhere so it can find/kill all the bad stuff.

Thanks for the clarification. Pumping to waste now and I’ll keep the thread updated with progress.

TFP!!

 

[CtP]

I drained it down to 2 feet in shallow end and refilled. Added a gallon of bleach tonight.
At what point should I retest CYA?
Is it important to maintain FC Levels relative to CYA during the drain & refill stage?
Definitely need to slam after this, pool is getting green.

 

[tim5055]

You can retest CYA once the pool is full and it has circulated for an hour or so.