Nitrate in pool water

Chlorinating, maintaining the right chlorine levels,
chlorine problems. Dichlor, trichlor, cal hypo, bleach,
granules, chlorine pucks and chlorine sticks.
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poolcarenovice
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Nitrate in pool water

Postby poolcarenovice » Sun 12 Nov, 2017 17:48

Is it true that the presence of nitrate in pool water at a concentration of 20 PPM or greater will drastically increase your sanitizer consumption? Thank you.


26,000 gallon, in-ground concete; Pentair Superflo VS pump; Pentair Quad D.E. Filter; Polaris 180 Vac-Sweep with booster pump
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Re: Nitrate in pool water

Postby Teapot » Mon 13 Nov, 2017 03:14

Hi Poolcarenovice, Not as far as I know, Nitrates are very basic compounds ( I don't mean basic as in the pH sense) just nitrogen and oxygen. Chlorine can break down chemical compounds but it pretty much stops at nitrogen and chlorine won't do anything to nitrates therefore you won't be using more chlorine.
An excess of nitrates or phosphates will provide food for algae which will use more chlorine via that route.

I took a moment to read your first post and you certainly live in an area of hard water and pretty high alkalinity so when you get your pool water into condition I would be loath to waste that water. I wonder what your rain water tests at? maybe harvest some of that for top ups?
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poolcarenovice
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Nitrate in pool water

Postby poolcarenovice » Tue 14 Nov, 2017 01:54

Teapot wrote:An excess of nitrates or phosphates will provide food for algae which will use more chlorine via that route.


Thank you. That is very informative. The water has looked blue and clear with no algae for months so I suppose I needn't worry about Nitrate.
FAC: 5
TAC: 5
CA hardness: 650-800
CYA: 99
TA: 120
pH: 7.6
Copper: 0
Iron: 0
TDS: 1,000
Phosphates: 0
Nitrite: 0
Nitrate: 15-20
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Re: Nitrate in pool water

Postby Denniswiseman » Tue 14 Nov, 2017 04:00

With a CYA of 100 your lowest FC should be 8ppm and a normal level of between 11-13ppm as indicated in the Chlorine / CYA Chart
Have you been chlorinating with pucks or granules
For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm
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Re: Nitrate in pool water

Postby Teapot » Tue 14 Nov, 2017 05:22

From the level of the CYA I'm guessing pucks? You'll need to switch to chlorine bleach (unscented thin from Walmart etc)
I wouldn't advise using Cal Hypo as the water seems hard enough as it is.
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Re: Nitrate in pool water

Postby poolcarenovice » Thu 23 Nov, 2017 13:00

Denniswiseman wrote:With a CYA of 100 your lowest FC should be 8ppm and a normal level of between 11-13ppm Have you been chlorinating with pucks or granules

I use Trichlor pucks in the summer only. CYA is now down to 90ppm and TC + FC are up to 10-13ppm.
26,000 gallon, in-ground concete; Pentair Superflo VS pump; Pentair Quad D.E. Filter; Polaris 180 Vac-Sweep with booster pump
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Re: Nitrate in pool water

Postby poolcarenovice » Thu 23 Nov, 2017 13:21

Teapot wrote:I wouldn't advise using Cal Hypo as the water seems hard enough as it is.

I don't use Cal Hypo. When last tested the fill water's CH was only 150ppm. I believe the high pool water CH is due to deteriorating plaster.
26,000 gallon, in-ground concete; Pentair Superflo VS pump; Pentair Quad D.E. Filter; Polaris 180 Vac-Sweep with booster pump
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Re: Nitrate in pool water

Postby Teapot » Fri 24 Nov, 2017 05:27

Hi Yes I think you are right, plaster becomes sacrificial in those cases. To stop the CYA getting so high, maybe you could do every other week with bleach especially if you are at the house.
CYA, cyanuric acid is an acid so when the level gets to high it could also be responsible for causing damage. ( other levels such as alkalinity can counter that but alkalinity can be unstable compared to CYA).
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Re: Nitrate in pool water

Postby poolcarenovice » Mon 15 Jan, 2018 20:57

Teapot wrote: I wonder what your rain water tests at? maybe harvest some of that for top ups?

We finally had rain and it tested at 0 for both nitrates & nitrates.
26,000 gallon, in-ground concete; Pentair Superflo VS pump; Pentair Quad D.E. Filter; Polaris 180 Vac-Sweep with booster pump

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