Accidentally added 5lbs of fertilizer to the pool

Discokatt

Member
Aug 2, 2021
19
France
Note to self: Don't store fertilizer in old pool chemical buckets...

Three biggest concerns are:
1. Lots of fertilizer in the pump - do I need to get rid of it?
2. Some green stuff on the bottom of the pool (see photos) - how do I get rid of it?
3. Anything else we may not know about?



07.08.21 Measurements:
FC: 0
PH: 6.6
TA: 93
CH: 355
CYA: 89
Phosphate: 2.9

After removing most of the fertilizer and doing a backwash and put the SWG on "boost", it now looks like this - is it OK? (TA is a bit high....):

07.08.21 Measurements (after We've added 3.6kg PH-plus (alkaline sodium carbonate/Soda Ash), 1.8L of Calcinex to decrease C, and 300ml Nophos to decrease phosphate)
FC: 4.0
PH: 8.0 (Note the PH expert)
TA: 130 (Note the PH expert)
CH: N/A (Can't measure)
CYA: 89 (assumed same as last measurement)
Phosphate: N/A (can't measure)

Thank you!

Fertilizer in pump:
IMG_9739.jpg

Green/Yellow stuff on pool floor:
PHOTO-2021-08-08-17-15-18.jpg
PHOTO-2021-08-08-17-15-02.jpg
 
Last edited:
With your data, I get 135 ounces of washing soda.

How did you measure a ph of 6.6 and a TA of 93. Neither of those test results are possible with a proper test kit.

I would not use washing soda, it will spike your TA. Use Borax if you feel you must raise pH chemically.
With a TA of 93, the pH will rise naturally quickly.
 
I used 3.6kg PH-plus (alkaline sodium carbonate) to raise the PH. Is that Borax or washing soda?
That is washing soda (aka soda ash). Your TA will now be much higher. Your pH will rise quickly.

Your signature shows a 15.8K gallon pool. Please edit that if not true.
 

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Fertilizer is likely algae food. You need to follow the SLAM Process and keep your FC up around 36 with your CYA. That will be difficult given your testing situation.

Can you drain the pool and refill with fresh water?

Recognize that draining pools have risks. Read…

 
Fertilizer is likely algae food. You need to follow the SLAM Process and keep your FC up around 36 with your CYA. That will be difficult given your testing situation.

Can you drain the pool and refill with fresh water?

Recognize that draining pools have risks. Read…

Are you sure I need to SLAM when I got most of it out and levels seem OK? What about the fertilizer stuck in the pump? Draining is not an option.

Why is iron a problem/how do I solve it?
 
As a couple of people have noted, you need your own proper test kit. The TF100, Taylor K-1766 salt test, and a SpeedStir are a good starting place. Then do an overnight chlorine loss test. End of day test the Free chlorine and chloramines. Leave your SWCG off and next morning test FC and CC again. If the FC has dropped, you likely still have algae.

And you've got to get that granular fertilizer out of the pump. Can you post a picture of your equipment setup?

I just noticed you're in France. Never mind the TF100 kit. Maybe you can find the Taylor K-2006 or 2006C. Speedstir and K1766, along with the K2006c are all available from Amazon, although I'm not sure about shipping. France is a modern industrial nation, at least from my recollection 20 years ago, so I'm sure you can find the Taylor or equivalent test kits locally.
 
I just noticed you're in France. Never mind the TF100 kit. Maybe you can find the Taylor K-2006 or 2006C. Speedstir and K1766, along with the K2006c are all available from Amazon, although I'm not sure about shipping. France is a modern industrial nation, at least from my recollection 20 years ago, so I'm sure you can find the Taylor or equivalent test kits locally.

EU regulations prohibit the importation or sale of the test kits we recommend.
 
Are you sure I need to SLAM when I got most of it out and levels seem OK?

Your pool is green/yellow. Likely due to algae but maybe the iron in the water.

One data point does not tell you if your levels are ok. You can do a Overnight Chlorine Loss Test
What about the fertilizer stuck in the pump?

Post pics of your complete equipment pad and plumbing.

You need to find access in your plumbing to rinse the pump out with fresh water.

I suspect that your sand filter has also been contaminated with fertilizer.
Why is iron a problem/how do I solve it?

Iron will deposit on your pool surfaces and stain it brown.

Some folks have successfully filtered iron out of the pool water using polyfill...

 
Your pool is green/yellow. Likely due to algae but maybe the iron in the water.

One data point does not tell you if your levels are ok. You can do a Overnight Chlorine Loss Test


Post pics of your complete equipment pad and plumbing.

You need to find access in your plumbing to rinse the pump out with fresh water.

I suspect that your sand filter has also been contaminated with fertilizer.


Iron will deposit on your pool surfaces and stain it brown.

Some folks have successfully filtered iron out of the pool water using polyfill...

As long as there is fertilizer in the pool, wouldn't an overnight chlorine test always result in chlorine being used? If so, is there any point?

I'm unable to get TFP-approved test kit here before I leave France, but today's readings are:
FC: 4.5
PH: 7.2 (PH expert probably added acid)
TA: 140
CYA: ~90

Please find attached picture of the setup:
IMG_9740.jpg
 
As long as there is fertilizer in the pool, wouldn't an overnight chlorine test always result in chlorine being used? If so, is there any point?
You have a choice.

Either drain the pool, flush the pool and equipment with fresh water, and refill.

Or use chemical treatments, ie. chlorine to kill all the organics in the fertilizer and filter out the non-organics and iron. Your sand filter probably has a lot of fertilizer in it and you may need to deep clean the sand or replace it before you are done.

Fertilizer has a lot of organics and phosphates as well as iron in it that is not what you want in pool water.

Please find attached picture of the setup:
View attachment 362859

It looks like you have unions that can be opened before and after the pump. I would turn off power in the pump, open up the unions, and see if you can get a garden hose in to flush clean water into one end and the fertilizer out the other end.

How has your filter pressure changed since adding the fertilizer?
 

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