Some Staining On Vinyl Liner

il_signore97

Member
Jun 8, 2021
7
Toronto, Ontario, Canada
Pool Size
9250
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Intex Krystal Clear
Hi all,

I started my first pool up earlier this year (above ground, vinyl lined, SWG) with the much appreciated advice from members here (thank you for that btw).

I've had the pool opened since early June and have had zero issues with it. I have a Taylor titration test kit for the water and maintain levels accordingly.

Currently, I'm sitting at:

FC - 14
CC - 0
pH - 7.1
TA - 100
CH - 100
CYA - 60

My SWG generally maintains the FC levels between 9.0 to 15 depending on bather loading and how often we use the pool. To my knowledge, FC has not dropped anywhere close to the min level for my CYA level.

Just a couple of days ago, I noticed that the liner is starting to develop very small areas of greenish stains near the bottom crease around the pool (along the vinyl liner seem). It's hard to imagine algae would be trying to bloom with the high-normal chlorine levels that my SWG maintains. The pump runs 24/7 with filter changes every 2 weeks. SWG runs at 100% for 5 hours straight every afternoon and this seems to be enough to maintain the levels accordingly (had it set to 7 hours initially but FC keeps creeping higher at that runtime).

The only other differences that I can think of as of recent is that we've been having some crazy wet weather (almost daily) and haven't used the pool for 2 weeks. Also in this time, we've had the pollen / helicopter leaves / other debris from the huge Maple trees in the area drop into the pool in large amounts. It's been hard to keep the pool clear of this junk with all the rain we've been getting. I've never had to brush the walls at all yet, and I just vacuumed last week because of the debris from the tree.

The pool is now relatively clean from debris and the water is crystal clear as far as I can tell (always has been so far). Do you have any words of advice for me? Do I just clean off the walls and be done with it?

Thanks in advance.

Jeff
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
33,813
Texas, San Antonio/Marion, South-Central Area
Pool Size
17888
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
I would be surprised to see organic growth with that high FC level. Instead, I would first try rubbing a Vitamin C tablet directly on the stained area to see if it's iron. If there's no change, try some dry acid in a thin sock or nylon rubbing it around on a stain to see if it's copper.
 

il_signore97

Member
Jun 8, 2021
7
Toronto, Ontario, Canada
Pool Size
9250
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Intex Krystal Clear
I would be surprised to see organic growth with that high FC level. Instead, I would first try rubbing a Vitamin C tablet directly on the stained area to see if it's iron. If there's no change, try some dry acid in a thin sock or nylon rubbing it around on a stain to see if it's copper.
Firstly, thank you for your advice and secondly, sorry for my late response. I finally had some time to investigate further and this is what I found...

I didn't have any vitamin c tablets on hand, but while I was cleaning the leaves with the pool skimming net, I noticed that the stained areas on the liner were not actually stained. There was a greenish / yellow coloured dust that was very easily removed with the end of the pool skimmer. No scrubbing required.

But now I'm worried that it might be mustard algae. I'm perplexed at how it could have crept in given the FC levels that my SWG maintains, but I'm a newbie so I also don't know much about algae.

Anyway, I think I have to proceed to slam the pool to get this under control before it gets out of hand.
 
  • Like
Reactions: Texas Splash

il_signore97

Member
Jun 8, 2021
7
Toronto, Ontario, Canada
Pool Size
9250
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Intex Krystal Clear
A picture says 1000 words, they say. 😁

Sorry, I should have taken a photo but I didn't think about it in time. Once I started the slam there was nothing left to see (thankfully).

I would agree - SLAM. Even with the elevated FC level, if enough organic matter settled in the pool and began to decompose and/or circulation was effected, algae can still try to grow. Best to catch it quickly. Good luck!

Thanks for the advice. It looks like it was mustard algae. The water was still perfectly clear but by the time I started the slam it was growing on almost all of the walls and most of the floor.

The slam has gone really well so far. I'm taking this slow and cautiously as this is my first time dealing with this. I raised the FC straight to the mustard algae level instead of the normal slam level (for my CYA measurement). The pool cleared up almost immediately, but I kept the slam going at the high FC level all week while I brushed all the dead algae dust from the walls and the floor. I vacuumed and brushed again yesterday and I don't see anymore dust coming off the surfaces as I did earlier in the week. So I think tonight I will do the overnight loss test to see if I'm done with it. I also cleaned all the pool toys in the water while the FC was at mustard algae level. Hopefully I've done a good enough job lol!

I'll keep you guys posted on the final result and thank you again for the advice. Much appreciated!
 
  • Like
Reactions: Texas Splash

il_signore97

Member
Jun 8, 2021
7
Toronto, Ontario, Canada
Pool Size
9250
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Intex Krystal Clear
Just be careful about the extra high FC level. The MA level was designed just for 24 hrs. Running for extended periods is different and we wouldn't want anything to happen to your liner. Something to keep an eye on. Good luck!

Thanks for the heads up... Being that I have a basic vinyl liner it doesn't appear that anything was affected by the FC levels that I used during the slam. All seems to be well so far.

Also, I realized that I forgot to come back and update everyone on the results (for the benefit of any future newbies like me who might find this thread through a search)...

It appears that the slam worked very well to rid the pool of the mustard algae. It passed an overnight chlorine loss test at 1 ppm of loss (it may have been lower than 1 ppm but I took the morning measurement a bit after the sun came out, so not sure if that affected the number). But in any case, I let levels return to normal and the pool has been fine since. The SWG seems to be maintaining levels around 8-9 ppm FC right now with current settings, and pH is now at 7.6 after the slam. The water is crystal clear and very comfortable to swim in. Hopefully it stays this way for the rest of the summer 🤞🏻

Thank you for the great advice.
 
  • Like
Reactions: Texas Splash

Enjoying this content?

Support TFP with a donation.

Give Support
Thread Status
Hello , This is an inactive thread. Any new postings here are unlikely to be seen or responded to by other members. You will get much more visibility by Starting A New Thread