Chlorine depletion?

[robbiem44]

Hi - I'm new to TFP (just found this site a couple days ago).

I have a 15,000 gallon in-ground plaster pool. I have been seeing what I feel is mustard algae visible on walls, steps and in-pool benches. I've shocked the you-know-what out of it, brushed the you-know-what out of it, and even treated it with Yellow Treat algaecide. The visible yellow algae had gone away, but what I'm noticing is: after shocking my chlorine levels are high, but then the next morning, they're very low again. This cycle has gone on repeatedly. Is it time to bring in a professional?

 

[mknauss]

Welcome to the forum! Do you have the package from the Yellow Treat? We need to know what the ingredients were.
You need to follow the SLAM Process. To do that, you need a proper test kit. I suggest the TF-100 or Taylor K2006C. A proper test kit is needed to get the accurate water chemistry results needed to follow the TFP protocols.

While you are waiting on your test kit, add 5 ppm FC worth of liquid chlorine / plain bleach to your pool each evening with the pump running. This will replenish the FC lost each day to the sun and also inhibit any algae in the water from growing further.

I suggest you read through Pool Care Basics - Trouble Free Pool and even look at a few of our videos TFP-TV - Trouble Free Pool

 

[Mdragger88]

How much of the Yellow Treat did you use?

 

[robbiem44]

Hi - thanks for your response.

I ordered a Taylor K2006 (I think I missed the "C"), and it should be arriving on Saturday. As far as Yellow Treat, it's 88.8% Sodium Bromide. I followed the instructions on the container.

I have taken my water to Leslie to get tested, and I found the chlorine levels consistently low after about 24 hours, in spite of adding shock (up to 2-3 lbs). My ph has tested high often, but I finally threw enough pH Down in there to get it around 7.5 (as tested by Leslie's).

Sorry, not following what you mean by "add 5 ppm FC worth of liquid chlorine." Not sure how to convert that into "ounces of bleach."

 

[robbiem44]

How much of the Yellow Treat did you use?

I used about a "cap and a half" each time. I treated it twice.

Thanks!

 

[mknauss]

Sorry, not following what you mean by "add 5 ppm FC worth of liquid chlorine." Not sure how to convert that into "ounces of bleach."

PoolMath
3 quarts of 10% liquid chlorine is 5 ppm FC in your pool.

How big is the cap of the Yellow Treat.
Our concern is if you have added sodium bromide, you now have a Bromine pool. Such that you need to drain it and refill with fresh water to properly manage it.

Sodium Bromide - Further Reading

www.troublefreepool.com

 

[Mdragger88]

Sorry, not following what you mean by "add 5 ppm FC worth of liquid chlorine." Not sure how to convert that into "ounces of bleach."

PoolMath

 

[robbiem44]

PoolMath
3 quarts of 10% liquid chlorine is 5 ppm FC in your pool.

How big is the cap of the Yellow Treat.
Our concern is if you have added sodium bromide, you now have a Bromine pool. Such that you need to drain it and refill with fresh water to properly manage it.

Sodium Bromide - Further Reading

www.troublefreepool.com

Each cap is 5 oz. So, if I added a cap and a half 2x over the last couple weeks, I guess I've added 15 oz of 88.8% sodium bromide to the pool over that time.

Drain/refill? Why would they sell this stuff it using it requires drain/refill? :-o

 

[robbiem44]

PoolMath

Thanks. Downloaded and installed. I put in 5ppm at 10% and got the same number mknauss came up with. Thanks!

 

[Mdragger88]

Each cap is 5 oz. So, if I added a cap and a half 2x over the last couple weeks, I guess I've added 15 oz of 88.8% sodium bromide to the pool over that time.

Drain/refill? Why would they sell this stuff it using it requires drain/refill? :-o

I’ve asked myself that twice this week!

 

[mknauss]

I would say that is enough to cause issues. Read the article I linked.
@JoyfulNoise @Donldson

 

[rcs29]

Each cap is 5 oz. So, if I added a cap and a half 2x over the last couple weeks, I guess I've added 15 oz of 88.8% sodium bromide to the pool over that time.

Drain/refill? Why would they sell this stuff it using it requires drain/refill? :-o

So that you never fix your issues. Then you feel hopeless and have to go back to them for more bogus chemicals ($$$). That or they are clueless or both. Rinse and repeat. Be thankful you've found TFP and won't be needing them anymore.

 

[Newdude]

Drain/refill? Why would they sell this stuff it using it requires drain/refill? :-o

Guess who gets to sell you a couple rounds of treatments when the first one doesn't work. Then guess who gets to sell you rebalancing chems when you give up and drain. When following poor advice puts you back at square 1, more yellow out will help.

 

[kul]

Welcome to TFP. Sorry you have been led astray by the pool store. It happens frequently. You are in good hands and I look forward to following your thread so I can cheer you on as you get control of your pool.

 

[C&HSewell]

Thanks. Downloaded and installed. I put in 5ppm at 10% and got the same number mknauss came up with. Thanks!

I promise you, if you follow what the gurus here advise you to do, your pool will be corrected and you will never be back in a pool store. Except maybe to buy recommended products, and even then you can get them from any box store or hardware store.

 

[robbiem44]

Welcome to TFP. Sorry you have been led astray by the pool store. It happens frequently. You are in good hands and I look forward to following your thread so I can cheer you on as you get control of your pool.

Thanks! Glad I found this place, albeit a few years too late. Up until now, I haven't had too many issues with keeping the pool in check; it's just this latest bout with what seems to be mustard algae, and rapid chlorine depletion. But, I'm all-in ... let's see how this goes!

 

[Mdragger88]

Sadly they sell lots of “magic” potions that are bandaids but not long term solutions & cause more problems than they solve.
Just hold tight & do the 5ppm of liquid chlorine/day until your kit comes.
Then you’ll have some good data & we’ll see what @JoyfulNoise calculates for that amount of bromide before calling for a water exchange.

 

[JoyfulNoise]

15oz (weight) in 15,000 gallons of water is going to add roughly 7ppm bromide ion to your pool. Chlorine gets used up quickly converting bromide ions to sanitizing bromine. Active bromine is very unstable to UV light and will quickly be reduced back to bromide.

So basically you’re seeing you chlorine deplete very quickly because the bromine is being formed and then reduced by UV light. This process will continue until the bromide concentration comes down which, on its own, will take a very long time.

So you have to decide if you want to keep fighting against the bromine induced chlorine loss OR drain and refill to try to get the bromine levels down.

 

[robbiem44]

Is there a way I can test the bromine/bromide to be able to know whether it's worth it to drain/refill? Does it make sense to turn add water to the bottom of the pool (by sinking my hose) to dilute the water over a period of time?

I guess once my test kit comes in, I'll have a good idea of just how much chlorine is being depleted daily, if I'm adding 5ppm of chlorine daily.

Thanks!

 

[Mdragger88]

Is there a way I can test the bromine/bromide to be able to know whether it's worth it to drain/refill? Does it make sense to turn add water to the bottom of the pool (by sinking my hose) to dilute the water over a period of time?

I guess once my test kit comes in, I'll have a good idea of just how much chlorine is being depleted daily, if I'm adding 5ppm of chlorine daily.

Thanks!

Once your kit comes you will also know how much cya & ch you have as well so if either are really high you can be sure to exchange the correct amount of water. There’s a reason you got algae in the first place- low fc in relation to your cya
FC/CYA Levels.
The fas/dpd kit can also test bromine levels.

Testing Bromine with a Taylor 2006 Kit

Are there different reagents to test from Bromine? I read that a chlorine test can be done and the result multiplied.

www.troublefreepool.com

Replacing water is only part of the solution.
To rid yourself of algae you will need to do the
SLAM Process after your water exchange.
How were you chlorinating previously?