Black/Mustard algae problem

[RadiatingOrange]

G’day, everyone!

I could use some help, please. I've recently taken over the pool in a share house. The previous tenant allowed it to turn green over the winter but cleaned it up before I moved in. However, all this brown/yellow stuff is really stuck to the bottom, and I can't vacuum it up. They claim it just needs to be brushed away.

I managed to brush the yellow stuff up(looks like mustard algae). The dark brown/green residue isn't budging, even with a steel algae brush. I wiped some on white paper and found it was green, pointing towards black spot?

I'm currently relying on pool store testing but have a ClearChoice Labs kit on the way (likely 2 weeks away with Christmas).

I’m not sure if I'm in a losing battle or have to wait for the test kit and SLAM the stuff to oblivion. I like the look of the TFP method and will plan to use it from now on.

Chlorine: above 5ppm
PH: 7.8
CYA: 50


Many thanks.

 

[Bperry]

G’day, everyone!

I could use some help, please. I've recently taken over the pool in a share house. The previous tenant allowed it to turn green over the winter but cleaned it up before I moved in. However, all this brown/yellow stuff is really stuck to the bottom, and I can't vacuum it up. They claim it just needs to be brushed away.

I managed to brush the yellow stuff up(looks like mustard algae). The dark brown/green residue isn't budging, even with a steel algae brush. I wiped some on white paper and found it was green, pointing towards black spot?

I'm currently relying on pool store testing but have a ClearChoice Labs kit on the way (likely 2 weeks away with Christmas).

I’m not sure if I'm in a losing battle or have to wait for the test kit and SLAM the stuff to oblivion. I like the look of the TFP method and will plan to use it from now on.

Chlorine: above 5ppm
PH: 7.8
TA: 120
CYA: 50
TA: 20 - can I add buffer anytime?

Many thanks.

You have two TA measurements. Can you fix that to make sure which is which cause one of them is super important for algae. You don’t want to increase the stabilizer too much if you are going to SLAM, but pool stores aren’t good at testing it so don’t add any until you test it yourself.

You will need to use the SLAM process but note it’s not a one and done thing. It’ll take a bit of time once the test kit arrives. You can safely add 5ppm worth of liquid chlorine every day until the kit arrives and brush well while doing it.

 

[RadiatingOrange]

You have two TA measurements. Can you fix that to make sure which is which cause one of them is super important for algae. You don’t want to increase the stabilizer too much if you are going to SLAM, but pool stores aren’t good at testing it so don’t add any until you test it yourself.

You will need to use the SLAM process but note it’s not a one and done thing. It’ll take a bit of time once the test kit arrives. You can safely add 5ppm worth of liquid chlorine every day until the kit arrives and brush well while doing it.

Sorry the second reading was a typo. I topped up the chlorine after it dropped and had the water retested at the store.

PH 7.9
Chlorine >5ppm
TA 150
CYA 60 - I haven’t touched this, so we’ll say unreliable.

I gave it a good brush and the water went green but the brown stuff remains very stubborn. Will it eventually come off? I’d like to avoid draining it.

 

[Bperry]

Sorry the second reading was a typo. I topped up the chlorine after it dropped and had the water retested at the store.

PH 7.9
Chlorine >5ppm
TA 150
CYA 60 - I haven’t touched this, so we’ll say unreliable.

I gave it a good brush and the water went green but the brown stuff remains very stubborn. Will it eventually come off? I’d like to avoid draining it.

Brown stain could be iron staining. A way to check for that is to rub some crushed up vitamin C tablets on the stain to see if it removes any. If it does, it’s iron.

But you need to get rid of all the algae before treating iron stains so one thing at a time.

Same store gave two CYA readings of 20 and 60? Keeping that in the thread helps people see how bad bad their testing is. Don’t be afraid of leaving them listed, no one here believes then anyway.

 

[Mdragger88]

Just do as suggested & add 5ppm of liquid chlorine each day & nothing else until your kit comes & brush as recommended.
Read up on the
SLAM Process so you can be sure to do all the things as outlined.
Get yourself a good supply of fresh liquid chlorine (at least 10 gal for now) & a good reliable source for getting more.
I see a trichlor floater in the picture- don’t refill that & remove it, it only increases your cya which makes slam level higher.
FC/CYA Levels
Your picture looks more like regular algae (regular algae can be many colors).
Even if it is mustard algae you must fully complete the slam process first before moving on to mustard algae protocols.

Mustard Algae

Today We are going to show you how you can get rid of mustard algae in your pool. By following the steps in this guide and with no expensive chemicals.

www.google.com

When your kit comes do all the tests & post them
Fc
Cc
Ph
Ta
Ch
Cya
& we’ll go from there

 

[RadiatingOrange]

PH 7.2
TA 150
Ch 100
CYA 50

Ok, the test kit arrived last week and I adjusted the Ph to 7.2. Started the SLAM and tested 4 times daily Saturday and Sunday. I’ve since been testing/adding chlorine at 0600, 1600, 2000 everyday. Brushing and vacuuming as well.

While the water is clearing up, the algae on the bottom doesn’t seam to be improving. I have become sceptical the 12.5% bleach from the pool store is actually much lower.

I tested FC at 9 and added 3.8 litres of 12.5% bleach (1 week old). Then waited 1.5Hours and tested again.
Fc 14.5
Cc 0
I’m confident in my water volume but something isn’t right.

Assuming my testing is correct I’m reading a chlorine drop of 8 over night and I0-12 in the day. We had had a heatwave with temperatures above 40C (105F), and UV at 13 all week.

Am I on the right track and just need to quintuple my brushing or is there something I’m missing?

I’ve sorted some bulk calcium chloride increase CH this weekend.

43K litre (11K gal), 12.5% Chlorine, Semi-IG Concrete, Sand Filter, Pump:280L/minute,

 

[Bperry]

PH 7.2
TA 150
Ch 100
CYA 50

Ok, the test kit arrived last week and I adjusted the Ph to 7.2. Started the SLAM and tested 4 times daily Saturday and Sunday. I’ve since been testing/adding chlorine at 0600, 1600, 2000 everyday. Brushing and vacuuming as well.

While the water is clearing up, the algae on the bottom doesn’t seam to be improving. I have become sceptical the 12.5% bleach from the pool store is actually much lower.

I tested FC at 9 and added 3.8 litres of 12.5% bleach (1 week old). Then waited 1.5Hours and tested again.
Fc 14.5
Cc 0
I’m confident in my water volume but something isn’t right.

Assuming my testing is correct I’m reading a chlorine drop of 8 over night and I0-12 in the day. We had had a heatwave with temperatures above 40C (105F), and UV at 13 all week.

Am I on the right track and just need to quintuple my brushing or is there something I’m missing?

I’ve sorted some bulk calcium chloride increase CH this weekend.

43K litre (11K gal), 12.5% Chlorine, Semi-IG Concrete, Sand Filter, Pump:280L/minute,

When you add chlorine test again after 30 minutes if you are trying to gauge whether you hit the target or not. If not, then increase your pool volume in the calculator or dose a % higher. Don’t wait three hours.

If you have green algae visible it may take some time. Don’t add calcium (or anything else) during a SLAM, in fact don’t test anything other than FC and CC during a SLAM. Sounds like you’re on the right track though. I assume your CYA number came from the test kit right? (Pool stores get that one wrong the most it seems)

 

[Mdragger88]

You’re off to the races! Good job
Your Slam level is 20ppm.
FC/CYA Levels
Do your best to maintain that - you seem to have a good schedule going!
Just be sure you’re actually reaching slam level. Check your next dose from that batch of chlorine after 30 minutes to determine if you need to use more going forward because its weak.
In the US we have date codes on the bottle so we recommend that you always check them before buying.

Chlorine Date Code Decoder - Further Reading

www.google.com

If you confirm that your bleach is quite weak you may be able to get a refund. Cuz its not cheap!

How can I test bleach for myself to confirm the concentration of Sodium Hypochlorite?

In the absence of my standard go-to 6% bleach at aldi, I went to Pinch A Penny Pool Supply and got a 2.5 gallon jug of supposedly 10.5% Sodium Hypochlorite. I am skeptical of that 10.5% concentration. Yesterday, my FC was 4.0 pp. , so I added 40 oz yesterday which should have bumped FC up by 2...

www.troublefreepool.com

You can use a 5ml sample and each drop counts as 1ppm for your frequent day time testing to conserve reagents. But stick with the 10ml sample for oclt. Until you’re clear with no visible algae there’s no reason to do an official oclt.
Be sure you get in & scrub any nooks & crannies too!
Do ALL the things
*Check & scrub every nook & cranny where algae may hide {light niches, steps (inside & out), drain covers, ladder handrails, skimmer throats/weirs, abandoned lines, autofill, overflow drains, seam flaps, etc.}
*If water can go there, algae can thrive there.
*Run slam level water through all water features & lines for at least a couple hours a day during the SLAM Process.
*Brush & or vac daily (this breaks up biofilms that algae uses to protect itself from chlorine)
*Backwash/clean filter when pressure rises 25%over clean pressure.