nitrates

[rmozer]

I've been having trouble this summer keeping the algae under control. It's been very hot and humid here on Long Island this summer and wonder if others are having trouble as well.

I have been monitoring my CYA levels, which seem to keep creeping upwards. I have lowered the pool levels to the bottom edge of the skimmers and refilled 2x times now. I've adjusted the FC levels to an appropriate shock level relative to the CYA levels, which is now at about 60. The water is clear, but I keep getting a coating of green algae on the bottom and walls even at these shock levels. It seems I've had my pool at shock levels for the better part of the summer, which I know is not good for the liner. After lowering the pool level and adding new "acidic" water from my well, I had to adjust my alkalinity levels, which are now at about 80.

Just recently, a friend of mine told me about someone who had a similar problem with her pool and it was determined to be a problem with high levels of nitrate. I have a simple water quality testing kit that said my nitrate levels were at about 20 ppm (prior to my latest draining and refilling effort). The kit is not very sensitive to nitrate, so my levels might actually be higher than 20 ppm. I also understand that the only way to reduce the nitrate levels is to drain the pool and refill it with new water.

My question to the forum is, at what levels do nitrates become a problem with regard to algal growth? It feels like my problem this summer is a moving target.

 

[jblizzle]

I have never tested or worried about nitrates or phosphates.

If you maintain the proper level of FC for your CYA, you should not get algae.
Sounds like you have kept elevated FC levels, but are you actually following the SLAM Process process? Have you passed the 3 criteria to stop?

How are you chlorinating? Why would your CYA be climbing?

 

[pabeader]

How often do you brush the areas in question?

 

[ajw22]

Chlorine kills algae.

Nitrates and phosphates feed algae.

If you have adequate FC levels doesn't matter how much food algae has it will not survive and prosper.

This is the critical chart for you [FC/CYA][/FC/CYA]

 

[rmozer]

Chlorine kills algae.

Nitrates and phosphates feed algae.

If you have adequate FC levels doesn't matter how much food algae has it will not survive and prosper.

This is the critical chart for you [FC/CYA][/FC/CYA]

Thanks.

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How often do you brush the areas in question?

I've been brushing it each time I add chlorine to shock levels.

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I have never tested or worried about nitrates or phosphates.

If you maintain the proper level of FC for your CYA, you should not get algae.
Sounds like you have kept elevated FC levels, but are you actually following the SLAM Process process? Have you passed the 3 criteria to stop?

How are you chlorinating? Why would your CYA be climbing?

I am using liquid Chlorox (6.05%) bleach.
I am using 3" tabs from Costco.
I don't know why my CYA seems to creep upwards.

 

[Grape Ape]

Thanks.

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I've been brushing it each time I add chlorine to shock levels.

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I am using liquid Chlorox (6.05%) bleach.
I am using 3" tabs from Costco.
I don't know why my CYA seems to creep upwards.

The tabs include CYA. You'll need to either stop using them or resign yourself to replacing water with some regularity.

I chose to save the tabs and floater for vacations and other times I cannot get to the pool for several days.

 

[scdaren]

I am using liquid Chlorox (6.05%) bleach.
I am using 3" tabs from Costco.
I don't know why my CYA seems to creep upwards.

In addition to avoiding the tabs -- you may want to stop using the Clorox brand bleach -- especially if it says it has "Cloromax" technology. Those are additives you don't want in your pool. Either use generic bleach with no additives, or look for 10 to 12.5% liquid chlorine at a pool store or hardware store.

 

[Grape Ape]

And the no-name stuff is significantly cheaper.

 

[rmozer]

The tabs include CYA. You'll need to either stop using them or resign yourself to replacing water with some regularity.

I chose to save the tabs and floater for vacations and other times I cannot get to the pool for several days.

I checked the 3" tabs and they are also made by Chlorox. I have a chlorine in-line feeder which I thought I needed to keep filled with the 3" tabs. No?
Please advise.

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In addition to avoiding the tabs -- you may want to stop using the Clorox brand bleach -- especially if it says it has "Cloromax" technology. Those are additives you don't want in your pool. Either use generic bleach with no additives, or look for 10 to 12.5% liquid chlorine at a pool store or hardware store.

I will check the Chlorox bleach I'm using.
It's convenient because I can pick it up at Costco for $8.69 for 3 bottles. Seemed pretty cheap, but if it is causing my troubles, I'll find another source of liquid chlorine.
Thanks.

 

[mknauss]

The tabs are made of Trichlor - which is chlorine (which you need) and Cyanuric Acid, which you do not need anymore of. I suspect the tabs also have copper in them which you do not want at all.

So you need to stop using the Trichlor for your chlorine requirements and use liquid chlorine/bleach.

What test kit are you using?

 

[domct203]

I checked the 3" tabs and they are also made by Chlorox. I have a chlorine in-line feeder which I thought I needed to keep filled with the 3" tabs. No?
Please advise.

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I will check the Chlorox bleach I'm using.
It's convenient because I can pick it up at Costco for $8.69 for 3 bottles. Seemed pretty cheap, but if it is causing my troubles, I'll find another source of liquid chlorine.
Thanks.

Using Trichlor tabs, you will add 6ppm of CYA for every 10ppm of FC added. Let’s say your pool uses 3.3ppm of FC daily, in 3 days you will have added 10ppm of FC, and 6ppm of CYA, in 6 more days it’s 12ppm CYA. In 12 more days it’s almost 25ppm of CYA. Before the end of the month you’ll be adding up to 50ppm of CYA with a daily 3ppm FC consumption average using Trichlor tabs.

We advocate the use of liquid chlorine, aka bleach, or a SWG system.

 

[rmozer]

In addition to avoiding the tabs -- you may want to stop using the Clorox brand bleach -- especially if it says it has "Cloromax" technology. Those are additives you don't want in your pool. Either use generic bleach with no additives, or look for 10 to 12.5% liquid chlorine at a pool store or hardware store.

I just checked and the Chlorox bleach I am using has the "Cloromax" technology. Could this be the reason I can't get rid of the algae?
In the meantime, I will look for another source of chlorine.
Thanks.
Bob

 

[mknauss]

Cloromax is a polymer additive. We do not recommend using it as we are unsure what the polymer additive may eventually do to filters, etc.

Best to find plain bleach or a Liquid Chlorine.

 

[rmozer]

The tabs are made of Trichlor - which is chlorine (which you need) and Cyanuric Acid, which you do not need anymore of. I suspect the tabs also have copper in them which you do not want at all.

So you need to stop using the Trichlor for your chlorine requirements and use liquid chlorine/bleach.

What test kit are you using?

OK on the tabs. I will stop using them.
I have the TFP test kit so I can monitor the FC and CC levels.
Thanks.
Bob

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Using Trichlor tabs, you will add 6ppm of CYA for every 10ppm of FC added. Let’s say your pool uses 3.3ppm of FC daily, in 3 days you will have added 10ppm of FC, and 6ppm of CYA, in 6 more days it’s 12ppm CYA. In 12 more days it’s almost 25ppm of CYA. Before the end of the month you’ll be adding up to 50ppm of CYA with a daily 3ppm FC consumption average using Trichlor tabs.

We advocate the use of liquid chlorine, aka bleach, or a SWG system.

Now I see why my CYA levels have been increasing.
I will stop with the 3" tabs and look for another source of liquid chlorine.
In the past, I was able to purchase Chlorox 8.25% liquid bleach at Costco and had no problem last year. I wasn't paying attention this year and just assumed I was buying the same product...NOT!
Thanks.
Bob

 

[AimeeH]

Hey Bob

In reading through this, you say you're bringing your FC up to shock level and brushing when you do. Are you elevating your chlorine to shock level for your CYA when you see algae or are you following through with the whole process of removing algae? We say SLAM

Shock
Level
And
Maintain

The idea being to elevate your FC to the shock level for your CYA and maintain it there-not letting it drop.....testing as often as necessary to keep the FC at shock level. Until you meet the 3 criteria:

1. Water is clear
2. CC is .5 or less
3. Overnight free chlorine loss (OCLT) is 1ppm or less

The important part is that it is a process and not one time addition of a lot of chlorine. As you've already read, you'd need to stop using dry sources of chlorine that add CYA too.

Pool School - SLAM - Shock Level And Maintain

 

[rmozer]

Hey Bob

In reading through this, you say you're bringing your FC up to shock level and brushing when you do. Are you elevating your chlorine to shock level for your CYA when you see algae or are you following through with the whole process of removing algae? We say SLAM

Shock
Level
And
Maintain

The idea being to elevate your FC to the shock level for your CYA and maintain it there-not letting it drop.....testing as often as necessary to keep the FC at shock level. Until you meet the 3 criteria:

1. Water is clear
2. CC is .5 or less
3. Overnight free chlorine loss (OCLT) is 1ppm or less

The important part is that it is a process and not one time addition of a lot of chlorine. As you've already read, you'd need to stop using dry sources of chlorine that add CYA too.

Pool School - SLAM - Shock Level And Maintain

We've had a lot of rain over the last few days and it's been hard to keep up with the chemistry.
It looks like I may have it under control, but I am concerned about what someone said about my use of regular Chlorox bleach with the Clormax additive. I just bought liquid shock from my local plumbing supplier who also sells pool supplies. It's 12.5% chlorine and I will use this from now on. I just hope the use of the regular chlorox hasn't created a different problem.
Thanks for your help.
Bob

 

[jeffchap]

AFAIK, the biggest problem with the polymers in the Chloromax is that they can cause your water to get foamy. This will go away in a day or two once you stop using it.

 

[rmozer]

AFAIK, the biggest problem with the polymers in the Chloromax is that they can cause your water to get foamy. This will go away in a day or two once you stop using it.

Thanks. I was concerned that it might be contributing to my algae problem.
Looks like I haven't been able to stick to the SLAM process.
It seems like I've had my chlorine levels between 15 and 20 ppm all summer, and I still have an algae problem.
Bob

 

[ajw22]

What is your current CYA level and what FC level are you going for during the SLAM Process?