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Clean pool of dark green algae

Dave-1
Home Improvement Guru

Clean pool of dark green algae

Oh yeah...

Summer is on its way and this weekend is supposed to get to around 31 degrees down here. (The green pool photo is to show we all have our pools like this at some point :smile: )

This the blackest green my pool has been after winter. Last year I had a deep green colour to start with and went light on the chemicals. It took 30 days to bring it back. This year it took 3 and a half days.

I am sure there are a lot of people with the same colourerd pool and I have always struggled to "get it right" It also feels embarrasing  to talk about so why not show how it can work.

So this is the path I took this year.

Pool type Fresh Water

Sand Filter

Aprox 45,000L

Overshadowed by trees which I really like

Steps

Step 1

Day 01

I challenge myself every year to get the pool back to clear, as fast as I can, either going light on chemicals or heavier. This year I followed the chemical instructions and really wish I had ALWAYS followed instructions! lol On Sunday my pool was black green in colour, I had a half winters worth of leaf matter in the bottom that you could not see and had just found out that 30deg weather was this coming weekend.

01 10-09-2023.jpgDay 01 Sunday Midday, Time to scoop out as much leaf matter as I can.

02 10-09-2023.jpg

I had three wheelbarrows worth from half a winterising of the pool (No pool cover) Also scrubbed the sides of the pool and the edges at the top as they were heavily discolured with algae

03 10-09-2023.jpg

This is the PH (8+) level before I topped up the water level of the pool. It was around 10cm (3") lower then it should be.

Instructions say get the PH to 7.4, Then shock with chlorine, Then ballance it again to 7.4. Next step afterwards is use Flocculent to bind the dead algae and get it to sink.

04 10-09-2023.jpg

Pool all scrubbed and scooped out. Thats 2 and a half hrs of work including weeding the concrete. My arms were dead!

05 10-09-2023.jpg

Where my leaves go to die.... Well to rot down :smile: The black patches are freshly scooped leaves from the pool

06 10-09-2023.jpg

After I had topped up the pool I checked the PH again and it was perfect :smile: (The container/strips are a few years old :surprised: but still work fine)

07 10-09-2023.jpg

The instructions for a heavily algaed pool is to get the PH right (7.4ish) and then shock with 4-5 times the normal amount you shock the pool with. I usually shock the pool with around 5 cups of chlorine once a week so that meant 25 cups of chlorine! :surprised: A bit over half a 10kg tub. Woooo Havnt dont that before! 

08 10-09-2023.jpg

I ran the pool pump using the filter for 12 hrs the next day, This afternoon was maybe 3 hrs worth and you can see the chlorine going to work on that algae! 

Step 2

Day 02

I walked out to a milky lookingpool, way better then the dark green from the day before!

09 10-09-2023.jpg

I was shocked! Seriously shocked at how good it looked after 18hrs... (Morning photo)

10 11-09-2023.jpg

Wooooo The PH is off the chart (I checked it in the afternoon 1 day ofter the shocking with chlorine, I ran the pump all day)

11 11-09-2023.jpg

Afternoon photo, was still amazed at how it was traveling.

12 11-09-2023.jpg

Check PH level again. was around 8 still.

13 11-09-2023.jpg

I threw in 2kgs of flocculent (the instructions show 400gms per 10,000L so 2kgs I mixed with water in a bucket and then poured over the pools surface.

14 11-09-2023.jpg

Just to show the flocculent I used as I will forget for next year.

15 11-09-2023.jpg

Instructions say run the pump on RECIRCULATE the water for 30 mins then turn off for 24-48hrs and let the algae bind and settle.

Step 3

Day 03

I walked out in the morning expecting to see not a lot as I have done this numerous years... Well I was wrong! I possibly yelled out in surprise :smile: The flocculent had really been working overnight. so in under 12 hrs I could see silt on the ledge and steps :smile:

17 13-09-2023.jpg

I couldnt get over the clarity of the water!

18 13-09-2023.jpg

Long live the dead algae! That silt is from the powdered chlorine (they bind the chlorine to a substance that disoves to make it powdered) and dirt silt plus dead algae.

19 13-09-2023.jpg

Far end of the pool you can see a piece of bark that I had missed :surprised: seriously I have not seen a pool clear this fast.

20 13-09-2023.jpg

Afternoon day 03 when I got home form work..

21 13-09-2023.jpg

My judgement level is how many steps down can i see... Well I could see all the way! 

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Instructions say to vacuum to waste so tahts what I did, It took 20mins and the pool dropped 10cm (3") but the dead algae is gone!

23 13-09-2023.jpg

I find if I vacuum in strips I disturb the silt less as I work. Also remember to empty the filter basket out as it will fill with fines.

24 13-09-2023.jpg

Time to top up the pool but it is effectivly clean! 3 and a half days compared to last years 30 days and running the pool 12 hrs a day :surprised: Kicking myslef for sure.

25 13-09-2023.jpg

A bit of a cleanup needed but thats the hose on the bottom of the pool :smile: 

EricL
Bunnings Team Member
Bunnings Team Member

Re: Clean pool of dark green algae

Hello @Dave-1 

 

Thank you very much for sharing your pool cleaning regimen. That shock treatment was really impressive and transformed your pool colour so quickly. A few more days and your pool will be ready for use.

 

Eric

 

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Dave-1
Home Improvement Guru

Re: Clean pool of dark green algae

Morning @EricL 

I did a quick vacumn yesterday arvo for leftover silt/dead algae and today Its time to check the PH and put some algeicide in I think. I am still shocked at how fast it came around. Tho 15 deg water temp might just be an inviting look not an actual swim at the moment :smile:

 

Dave

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