Purple / Indigo algae. Sticking to steps and bottom of pool

[bexter111]

Hi,
I have a new-to-me pool. The previous owner only concerned himself with chlorine levels and as a result left me with a highly chlorinated, extremely acidic pool. He and I added a gigantic bag of baking soda last summer, and I added more 10 days after opening the pool. Just before closing the pool and after opening it, my pool guy and I noticed this purple/indigo colour as well. I foolishly went to the pool store before reading all of this, and added what I believe to be something similar to baking soda. The alkalinity and ph are now ok and I would like to focus on the purple. What do I do now? When I brush it/vacuum, it brushes away, but it always returns.

By the way, the heater is not hooked up. Pool store lady suspects the high acid burned through the heater rendering it useless. Thanks!

 

[PoolStored]

Welcome to TFP!!!!

Can you post some pictures? It would really help...

 

[bexter111]

I have been doing some homework. I was unable to find any info on here about anything purple! Here are some photos. The first photo is where I brushed the bottom, so it moves around easily. The second and third photos are to show the colour that shows up after it is out of the water. On another site it said there may be magnese in the water. I thought getting the alkalinity and ph balanced was my #1 priority. The guy who closed and opened my pool said he has not heard of a purple pool that is not hooked up to a heater.

I am having some difficulty with my pump as well, not filling up all the way with water, so today I will be checking all gaskets and hoses.

 

[JamesW]

Probably copper cyanurate.

 

[JamesW]

https://www.poolspanews.com/how-to/maintenance/when-pools-turn-purple_o

Avoid Opening Pools to Copper Stains

It's pool opening time in many parts of North America. What a drag to pull off the cover and find a copper stain known as purple haze.

www.aquamagazine.com

Purple (Copper) Cyanurate

There are big purple stains all over the walls & skimmer and other equipment. You've tried treating it as Pink Slime, but nothing's happening. You've shocked the pool, added algaecide, and still nothing. The good news is, you have a treatable problem. The bad news is, you're probably NOT...

parpools.typepad.com

 

[JamesW]

Google search results

www.troublefreepool.com

 

[Texas Splash]

Good to see James already replied for an expert set of eyes. @bexter111, can you post a full set of water test results please?

 

[bexter111]

Thank you for the article! I know I will not be relying on the pool store in the future, but I do not currently have a test for CYA. At the store it was 150 and 130. According to your article,
"This problem is most common in pools that have cyanuric acid levels measuring above 100ppm."
The pool store recommended getting the alkalinity under control, then focusing on the 0.5 metals detected using 0.9L of Pool Magnet Plus, then Filter Brite.
The article you mentioned recommends a partial drain and then "add a non‐phosphate metal control product to deal with the copper that still remains." Can I do a partial drain by vacuuming? Is there a different product out there that would be recommended?
Thanks so much everyone.

1st attachment: Pool store original numbers May 13 - I left wthout buying anything as I had 16lbs of baking soda at home:

2nd attachment: Pool store levels after I added 16lbs of baking soda. Pool store lady said not to worry about metals until the other levels were in check.
Instructions: I added one bucket in 3 doses of Balance Pak 100, which is just 1000g/kg sodium hydrogen carbonate (sodium bicarbonate). I understand now it was just more baking soda and I feel sheepish!
I also added the 1/2 container of liquid chlorine the previous owner left to bring level up.

My own levels as of yesterday: FC more than 3.6 (very yellow), pH 7.4, TA 180 or so. My testing kit says to add 2 drops if chlorine is high so I'm not sure how accurate my numbers are.

Thanks for the help everyone

 

[Texas Splash]

James may return shortly, but I'll make note of a couple things. First, if we believe the store testing to be accurate (always questionable), your pH is way too low making the water very aggressive and can cause corrosion to equipment and damage the liner over time. This could explain why your metals test was high (perhaps copper), and yes, that is a problem. Your pH should be between 7.2 - 7.8 and never below 7.0. Since your CYA appears to be too high, it would seem reasonable that you have been using chlorine tablets in the past correct? Tabs are acidic which can lower pH and TA, but then also add stabilizer (CYA). If you have tabs in use, remove them right away.

 

[Texas Splash]

I see a large water exchange in the future. That would do two things: Lower the CYA to a more manageable level (ideally around 50 or so) and remove some of the metals from the water. At that point you could start fresh and balance your level proper with your own test (proper) kit.

 

[bexter111]

I see a large water exchange in the future. That would do two things: Lower the CYA to a more manageable level (ideally around 50 or so) and remove some of the metals from the water. At that point you could start fresh and balance your level proper with your own test (proper) kit.

OK. I'll look up how to do that. I have a very basic test kit right now. The colour of my pool is exactly like the video/article so copper cyanurate would be the diagnosis for sure. Previous owner showed me the ropes. He loved his chlorine pucks and "shocking" the pool but made no mention of balancing the pH or alkalinity. I don't think that was on his radar at all. For *years*. I hope to restore the pool (and the house and property - there's a trend...) to its former glory.

 

[Texas Splash]

This article may help you.

Draining - Further Reading

www.troublefreepool.com

 

[bexter111]

Thank you - you have been most helpful!

 

[bexter111]

Thank you - you have been most helpful!

The road was very purple after cleaning the bottom of the pool and directing it there! I have taken water out using waste and added in water using the hose. Tomorrow I will do some more. We are expecting some rain tonight and I hope that will help my levels some.

 

[bexter111]

This article may help you.

Draining - Further Reading

www.troublefreepool.com

I know it has been over a year, but I wanted to thank you so much for your help. I got my pool under control and I will NOT be using the previous owner's chlorine pucks! I have been having fun with Pool Math and doing everything except covering/uncovering the pool myself.
Thanks again! I look forward to reading more in this forum.
Rebecca

 

[Texas Splash]