Mustard algae after long winter close

Apr 18, 2015
52
Tulsa, Oklahoma
Pool walls, spa, pool floor covered with brownish yellowish film. Been slamming for over a week.

FC 16
pH 7.6
TA 60
CH 0
CYA 0

Pool water sparkling clear. Staining on walls where pool level was during winter. Pool started out as a green brown mess. Making headway but losing confidence and lots of $ via bleach purchases.

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Yea, doesn't look like mustard algae to me.

If you have "staining" on the walls where the water level was during winter, I bet that's an algae ring. If so, it requires really vigorous and repeated brushing as the "ring" has a really strong biofilm which protects it from getting destroyed by chlorine. Scrub, scrub hard, and scrub hard often. The only way to break that kind of biofilm is to scratch deeply into it so the chlorine can get inside and kill it.

I am willing to bet that your FC will drop significantly. The good news will be that the FC is dropping because it finally has a job to do.

I could be wrong, but I have seen it before. Go scrub (Hard...) those walls like you've never scrubbed before and see what happens.
 
Jezza is spot on the money. A SLAM at 0 CYA is a hugh consumer of chlorine.

Add enough CYA to get to 30 and start using the SLAM values in Pool School based on 30 PPM immediately. That'll be a great help.

Secondly, Brush, brush, brush like BOY and MP have suggested.

Your're near the end. Review the instructions in the SLAM article and make sure you are doing everything there.
 
there is slight clouding when i brush. little puffs of what look like dust, but the stain doesn't go away, it remains. i have not tried to do an OCLT yet. i need to do that.

tonight, these were my measures:
FC 11, CC 0.5 (if any, very slight tinge of pink), i loaded 5 jugs of bleach and brushed for an hour!!!
pH 7.8-8.0, i added a gallon of muriatic acid
TA 100
CH 0
CYA 0-10, i'm adding stabilizer via sock in skimmer

i'm getting there, i can feel it. just have to keep hammering the stubborn spots......brushing 2x per day......

thanks for the response!

ryan
 
thanks Marian! i have not tried to do an OCLT yet. i need to do that.

i've been upping our brushing frequency and force! seeing some headway.

tonight, these were my measures:
FC 11, CC 0.5 (if any, very slight tinge of pink), i loaded 5 jugs of bleach and brushed for an hour!!!
pH 7.8-8.0, i added a gallon of muriatic acid
TA 100
CH 0
CYA 0-10, i'm adding stabilizer via sock in skimmer

i'm getting there, i can feel it. just have to keep hammering the stubborn spots......brushing 2x per day......

thanks for the response!

ryan

- - - Updated - - -

i'm adding stabilizer....still at 0-ish.....added a full sock worth of stabilizer a couple of days ago. even more tonight.....

thanks, ryan
 
Thanks Dave. Will get the CYA up. Need to re-read the SLAM article and make sure i'm staying on top of things and being diligent. and keep brushing! i'm starting to question my decision to close the pool over winter. i only placed a leaf net over the pool and occasionally swept the pool net of leaves, but basically all rain water and dirt entered the pool and stayed there for about 5 months....... the amount of effort to open the pool up, and expense of slamming seems to be greater than the effort to keep the pool open.

thoughts on this?

thanks,
ryan

- - - Updated - - -

still blue, clear, brown issue still around. upping the intensity of the slam and need to follow the guidance closer.....don't let the FC drop below slam value. i'm adding CYA since 2 days ago. tested and CYA still at 0. heard it can take a couple of days to show up on the test.....i may need to buy more. i think i added maybe a pound of stabilizer powder via sock in skimmer.

thanks for the encouragement.

ryan
 
You'll have to wait for someone else on winter questions. I don't know.

CYA/stabilizer: once you put it in the pool it stays forever at that level unless it either splashes out, is backwashed out, or you let the FC drop to zero and get unlucky about ammonia. So, let's try this to get an idea about your current level: use pool math, put in your gallons, then scroll to the very bottom and do the math on the total amount of stabilizer/cya you've added this month and see what it says the effect of adding it is for your size pool. Share that.

Then, roughly how many times have you backwashed since adding any stabilizer this month.

That should give us a number to expect. As far as I know, since you're holding FC ammonia isn't in the picture, which would mean if your test doesn't show about that pool math calculated level of cya in a couple days, odds are you're going the test wrong or the chemicals went bad.

Don't add any more cya without an expert telling you to here.
 

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i'm adding CYA since 2 days ago. tested and CYA still at 0. heard it can take a couple of days to show up on the test.....i may need to buy more. i think i added maybe a pound of stabilizer powder via sock in skimmer.

I'm not an expert, but I just checked pool math and for a 30000 Gal pool like yours, it said it would take about 7.5 lbs of stabalizer to raise the level from 0 to 30ppm. If you have only added 1 lb of stabalizer, it looks like you simply have not added enough to register on the test.
 
ugggh, still fighting this thing.......solid week of keeping the chlorine way high........do i need to be at FC 30 even if my CYA is <10? stubborn spots on shady walls still showing the algae.......have a more pronounced splotchy brownish pattern on pool floor.......brushing 2 times per day with wire brush, HARD.....with all of the muscle i have and i'm a big dude.......

any risk in slamming it with dichlor since my CYA is so low??? wondering if dichlor powder might be cheaper than 5 gallons of bleach per day ($15)......also, any concern with adding some algaecide to see how it does?

wondering if i let chlorine slip below slam level for just a part of a day, does that take me back to square 1? seems very difficult to achieve..........

pool overall looks good so we're going to let chlorine level come down so kids can swim with cousins over memorial day weekend, then resume the battle on Monday........

jeez, i'm gonna learn from this and not let my pool go so bad over winter.......

i know i'm whining (thanks for listening),
ryan
 
You need to bring your CYA level up to 30. It helps protect your chlorine from the sun. Also, an FC level of 30 is WAY to high for your CYA level. Here is a link to the chart showing the relationship:

Pool School - Chlorine / CYA Chart

Stay away from the algacide. Some cause more harm than good, the accepted ones are a preventative and won't help when you already have algae. Stick with bleach, but get some stabilizer in your water so you are not fighting the sun too.

As long as you keep your FC above the minimum level shown in the chart, you shouldn't be losing ground, but the closer you keep FC to your slam level (right now this is 10FC for you) the faster your slam will go. Since you do not have much CYA in your water you are losing a lot of chlorine to the sun every day.

Another note, it is safe to swim with FC levels at or below your SLAM level, so until you get your stabilizer up, that number is 10FC for you.
 
You need to bring your CYA level up to 30. It helps protect your chlorine from the sun. Also, an FC level of 30 is WAY to high for your CYA level. Here is a link to the chart showing the relationship:

Pool School - Chlorine / CYA Chart

Stay away from the algacide. Some cause more harm than good, the accepted ones are a preventative and won't help when you already have algae. Stick with bleach, but get some stabilizer in your water so you are not fighting the sun too.

As long as you keep your FC above the minimum level shown in the chart, you shouldn't be losing ground, but the closer you keep FC to your slam level (right now this is 10FC for you) the faster your slam will go. Since you do not have much CYA in your water you are losing a lot of chlorine to the sun every day.

Another note, it is safe to swim with FC levels at or below your SLAM level, so until you get your stabilizer up, that number is 10FC for you.
Thx.

Sent from my SAMSUNG-SM-G920A using Tapatalk
 
My apologies for missing the fact that your CYA was low. You mentioned DiChlor. Is that because you have some on hand? It would probably be better to just add some pure CYA to the pool as it is less complicated chemically. Whatever you choose to do, get that CYA up pronto.
 
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