I developed an algae bloom for the third time this spring

[stoney65]

Re: I developed an algae bloom for the third time this sprin

Typically, pools with the recommended range of CYA loose 2 to 3 PPM chlorine each day. For your 32k gallons, you will need to use one of the following each day:
133 oz. of 6% bleach
97 oz. 8.25% bleach
66 oz. 12% bleach
9.3 oz. trichlor (pucks)
15 oz. dichlor (powder)
18 oz. cal-hypo (powder 48%)
SWG

Any option except for the liquid chlorine (bleach) or SWG add other things that cause the problem like high CYA and high CH. That is why we recommend liquid chlorine or a SWG except for some very unusual cases.

Keeping trichlor tabs in 2 skimmers last summer lasted almost a week and 3 lbs of stabilized shock every week kept my chlorine level acceptable levels though until recently, I had no idea what cya levels really were, or their affect. I'm sure the previous owner used nothing but the same regimen since 2005 when he put in the pool.

 

[chem geek]

Re: I developed an algae bloom for the third time this sprin

It was my understanding from what I've read here that lowering the cya should lower chlorine usage too.

Well, it's more complicated than that. If the CYA gets high and the FC is not raised proportionately with it, then algae can grow and that clearly uses a lot more chlorine to keep it at bay or to frequently shock to get rid of it. However, if there isn't algae, say because you are lucky that the level of algae nutrients (phosphates and nitrates) is low, then the rate of chlorine loss will be lower because the higher CYA level protects the chlorine more and your FC/CYA ratio is lower.

So you may end up using more chlorine on a daily basis than you did before (not counting the amount for shocking), but your pool will remain in good shape consistently. When you get your CYA lower, you can experiment with different levels to see what works best for your pool given the amount of sun in your area. You can see what CYA level in the 50 to 80 ppm range works best for you. The higher CYA level requires a higher FC target, but overall the daily loss of chlorine is somewhat lower. It's harder to shock a pool with a higher CYA level (because it requires a higher shock FC target) so it's generally better to use a lower CYA level if the daily chlorine usage is acceptable, but again this is up to you based on how your pool behaves.

 

[rdhetrick]

Re: I developed an algae bloom for the third time this sprin

Tabs and weekly shocks have worked for many people for many years...until one day they don't and they can't get rid of the algae...like you have been dealing with this year. When the CYA gets to a point where the tabs/weekly shocks are no longer able to sustain a high enough FC, algae can grow. Getting rid of algae with high CYA is a real pain but it can be done and it takes a LOT of chlorine. Once it's gone, they go back to the tabs/weekly shock that don't work anymore, and soon, algae is growing again. The only real long-term solution is lowering the CYA through water replacement.

One situation where people can get by with tabs/weekly shock is when there is a short swim season, and they do a substantial drain for the winter. However, algae outbreaks at the end of the swim season often occur because the CYA gets high by then.

If you don't mind a water replacement every so often to lower the CYA when the algae comes, it's fine to use tabs/shock. It's just not the approach we follow and teach here.

 

[stoney65]

Re: I developed an algae bloom for the third time this sprin

Tabs and weekly shocks have worked for many people for many years...until one day they don't and they can't get rid of the algae...like you have been dealing with this year. When the CYA gets to a point where the tabs/weekly shocks are no longer able to sustain a high enough FC, algae can grow. Getting rid of algae with high CYA is a real pain but it can be done and it takes a LOT of chlorine. Once it's gone, they go back to the tabs/weekly shock that don't work anymore, and soon, algae is growing again. The only real long-term solution is lowering the CYA through water replacement.

One situation where people can get by with tabs/weekly shock is when there is a short swim season, and they do a substantial drain for the winter. However, algae outbreaks at the end of the swim season often occur because the CYA gets high by then.

If you don't mind a water replacement every so often to lower the CYA when the algae comes, it's fine to use tabs/shock. It's just not the approach we follow and teach here.

My algae problem this spring was caused because I neglected my pool over the winter. After I shocked a couple weeks and used tabs like I should have over the winter, I found the bbb system, and since then my pool is sparkling blue. The only reason I'm even considering replacing over 40, 000 gals of water now is the prospect that it would lower my chlorine usage.

 

[linen]

Re: I developed an algae bloom for the third time this sprin

The problem with your very high cya, is we really don't know how high of a FC you need to protect against algae. Generally, a FC level that is 7.5% of the cya level would work in normal cya ranges, but you are in uncharted waters. If your cya is really 320 then that would be a minimum 24 ppm FC at all times.

If you are even remotely up towards 200-300 ppm cya, you really do need to lower it.

What minimum FC level are you maintaining?

 

[stoney65]

Re: I developed an algae bloom for the third time this sprin

The problem with your very high cya, is we really don't know how high of a FC you need to protect against algae. Generally, a FC level that is 7.5% of the cya level would work in normal cya ranges, but you are in uncharted waters. If your cya is really 320 then that would be a minimum 24 ppm FC at all times.

If you are even remotely up towards 200-300 ppm cya, you really do need to lower i

What minimum FC level are you maintaining?

Like I said earlier, it might get below 1 now and again, but I always add a couple gals immediately and it goes up to 5, the next morning.

 

[linen]

Re: I developed an algae bloom for the third time this sprin

Our recommendation is a drain/refill...but it is up to you if you want to wait until you perceive a problem.

 

[UnderWaterVanya]

Re: I developed an algae bloom for the third time this sprin

Let me wade into these waters...

First - if you go by BBB - you need a lot more FC than 1-5ppm with a CYA level of 320.

Second - if you go by Pool Industry norms, then you don't need much advice from folks here about chemistry but you are welcome to ask - you just may get very sick of hearing about how you are not following the program.

Third - The Taylor CYA testing is a bear in artificial lighting. Despite knowing this pool stores simply ignore this and do it anyway. I have tried a number of options and all of them gave me lower than accurate numbers in unpredictable error ranges. Also when you use the dillution method this increases the inaccuracy - widening the error range. The CYA test starts out with about a +/- 15ppm error range - at 4:1 it is around +/- 60 - this doesn't mean that you aren't really high, but it does mean that you should remeasure as you do the drains (if you do them) before you assume how much to dump.

Fourth - Drain and refill can be done with other means - you can use a sheet of plastic or a gentle pull from the deep end and a gentle refill on the shallow end. The costs associated with a sheet/tarp can be prohibitive so we rarely recommend it - but we also rarely see CYA of 320. if water is very expensive then the option to use a barrier sheet should be considered.

EDIT - I nearly forgot - HANG IN THERE!!!!

 

[stoney65]

Re: I developed an algae bloom for the third time this sprin

Typically, pools with the recommended range of CYA loose 2 to 3 PPM chlorine each day. For your 32k gallons, you will need to use one of the following each day:
133 oz. of 6% bleach
97 oz. 8.25% bleach
66 oz. 12% bleach
9.3 oz. trichlor (pucks)
15 oz. dichlor (powder)
18 oz. cal-hypo (powder 48%)
SWG

Any option except for the liquid chlorine (bleach) or SWG add other things that cause the problem like high CYA and high CH. That is why we recommend liquid chlorine or a SWG except for some very unusual cases.

And THAT's the whole rub of it. I'm almost positive the cya tests done by leslies at 40 are probably correct then. This has been confirmed by taylor tech. I'm getting the same 4088 test system leslies uses as it is so much simpler to get an accurate reading and per the tech, does NOT require special lighting. For the last several weeks, I've pretty closely maintained a 1-5 ppm FC level by adding 2 121 oz bottles of 8.25 bleach every third evening, so, I'm obviously using less than 2ppm /day. My pool is remarkably clear blue water appearance since I started using bleach about a month ago now. My k2006 tester has never shown up on the scale.

 

[UnderWaterVanya]

Re: I developed an algae bloom for the third time this sprin

For the last several weeks, I've pretty closely maintained a 1-5 ppm FC level by adding 2 121 oz bottles of 8.25 bleach every third evening, so, I'm obviously using less than 2ppm /day. My pool is remarkably clear blue water appearance since I started using bleach about a month ago now. My k2006 tester has never shown up on the scale.

If you use poolcalculator.com and plug in the amounts of solid chlorine you have added that is either dichlor or trichlor and the size of the pool and figure in the amounts of dilution you have had you will see that you would have a hard time only being at 40 CYA over even a short timeframe.

BTW - Is there any reference to the test that shows that you can use the sliding model in artificial light? I have never heard that.

It's unclear to me if you understand what CYA levels do to chlorine use:
HIGH CYA = lower use of chlorine per day - but a higher level required to fight off nasties in the water.
LOW CYA = higher (percentage) use of chlorine per day - but a lower level required to fight nasties.
Typical losses are based on specific CYA levels, sunshine amounts and FC levels. With low sunlight, and HIGH CYA, and low FC your losses per day will likely be very low compared to High Sunlight, Moderate CYA and Adequate FC... so it may seem cheaper now but when something goes wrong it will be complicated and expensive to fix...

Another key is that water that looks clean may or may not be. Unless you perform an overnight chlorine loss test with a FAS-DPD test and see that you lose < 1ppm of Chlorine you can't know if you have a nascent infestation waiting in the wings. BTW this test needs to be done at shock levels to be accurate...

 

[stoney65]

Re: I developed an algae bloom for the third time this sprin

Edit. Butterfly Here's what I'm saying.
1. I have no idea exactly how much dichlor/trichlor had been used in my pool over the years. I'm assuming quite a bit. But I've been using it for most of the year I've owned it. Up until recently, I had no idea what cya was. Until a month ago, my testing consisted of using 6 way test strips, and mostly taking a water sample to either Leslie's, who uses a Taylor testing system or a local hardware store (using a bioguard system) whose last test was 80. Historically, my Cya results at Leslie's were 100 or less. The last couple tests done there were 40. Both performed by a different tester than had done my tests previously although using the same 4088 test system.
2. Because of the big difference between my tests since I got my k2006 tester and the tests performed by both Leslie's and the hardware store, I called Taylor technologies for advice. They said to make sure the tests at Leslie's was being performed correctly and told me exactly how the 4088 tests were performed. I took a sample there the next day and watched closely while she performed the test--it was done exactly how Taylor said it needed to be done. I called Taylor again yesterday to give the tech the results. She told me that I should rely on the Leslie's 40 result which duplicated their previous test instead of my own test. Considering my water clarity hasn't changed in the last month after using bleach. And never having a FC over 5 during the entire time. Obviously, my Cya tests were wrong because there haven't been any nasties observed.
2. I ordered a 4088 tester and asked specifically if it required special lighting. The tech said no! Nor even tfp's instructions indicate special lighting is required for a 4088 test.
3. Despite all the insistence that I have to drain and replace 84% of my water, I refuse to do it based on what both I and Taylor believe are faulty tests performed by me. I believe in the BBB system, and will continue to use it. I respect all the knowledge and experience here. And where advice is consistent with common sense, I'll gladly use it, but draining what appears to be a very healthy pool is not common sense. I can't explain the vast differences in the cya results, but so far, neither have any of you. I'll try doing the cya tests using my own tester when it arrives, and let you know the results. Thanks for your help, it IS appreciated.

 

[chem geek]

Re: I developed an algae bloom for the third time this sprin

I'm getting the same 4088 test system leslies uses as it is so much simpler to get an accurate reading and per the tech, does NOT require special lighting.

That's pure baloney from the tech. The 4088 cylinder is ABSOLUTELY POSITIVELY dependent on lighting conditions. If you don't believe that, try reading it in the dark! The exterior light is what shines into the sides of the tube and is why the tube is clear as it illuminates the cloudy precipitate and such scattered light makes it harder to see the black dot looking down into the tube. The only advantage to the 4088 is that you can move the black dot up and down, but with the standard tube in the K-2006 or TF-100 all you have to do is pour the solution back into the bottle and add it back to the tube as many times as you want.

The ability to distinguish a black dot against a white background is absolutely dependent on the overall lighting conditions and is why fine detailed work is done under bright lighting. To have increased contrast between a black which mostly stays black independent of lighting vs. white which varies directly with the intensity of the lighting, one needs brighter lighting.

I have had communication with the scientists at Taylor who know the tests well, not the people on the phone who are sales or technical support, and they were the ones that told me that they use a standard lighting condition that is roughly equivalent to standing outside with your back to the sun holding the tube in front of you. It's strong indirect lighting. Also, you can buy a 50 ppm CYA standard solution to verify that you are doing the test -- any of the CYA tests -- correctly and that your reagents are in good shape.

The only system where the lighting conditions won't matter is where you use a photometer that has its own light source.

However, lighting conditions won't turn a 100++ CYA into a 40 ppm CYA or vice versa. Variations in lighting conditions vary the CYA reading somewhat, but not that much. Having the black dot obscured because the mixture is so cloudy that you don't even get close to the 100 ppm line near the bottom of the tube is a whole lot different than 40 ppm which is much further up the tube (see the tube here). Of course, someone can mistakenly misinterpret the test by not determining when the black dot is obscured as shown in these photos, but that kind of mistake will be independent of the type of viewing tube that is used.

Finally, if you mix the CYA reagent with the pool water sample and it is very, very cloudy, then your CYA is very high, period. It doesn't matter what tube you put it into. So maybe either your reagent or the Leslie's reagent is bad -- yours in producing too much of a cloudy precipitate (which I find unlikely) or Leslie's where the melamine has been degraded (also unlikely, but possible). Also, given a history of using stabilized chlorine products (Trichlor, Dichlor) it is not at all surprising to have a high CYA level.

 

[YippeeSkippy]

Re: I developed an algae bloom for the third time this sprin

I hope the OP took advantage of the ginormous rain storms we've had in the area this past week! They went from my area right up to his... inches and inches!! I bet 10 inches (at least!) put a nice dent in his presumably high CYA level.

 

[stoney65]

Re: I developed an algae bloom for the third time this sprin

I hope the OP took advantage of the ginormous rain storms we've had in the area this past week! They went from my area right up to his... inches and inches!! I bet 10 inches (at least!) put a nice dent in his presumably high CYA level.

Presumably haha 4-5 inches Max for the three days of storms. Not even close to a dent in a 32000 gal pool.

 

[harleysilo]

Re: I developed an algae bloom for the third time this sprin

I want one of the 4088 tubes, just kinda makes sense like the speed stir. No need to slow pour, then pour back etc. Just fill it and slide it, correct?

I started a thread awhile back (could-you-test-cya-in-complete-darkness-with-speedstir-light-t58833.html) about doing the testing using the speed stir with it's light in the dark. My reasoning is that, or a large artificial light in my house, would be the easiest to dublicate, so that lighting is taken out of the equation as it is constant test to test.

I've yet to re-test CYA, i will this weekend, outside sun to my back, and then i'm going to walk into the dark and use speedstir light and see what i get.

 

[stoney65]

Re: I developed an algae bloom for the third time this sprin

I want one of the 4088 tubes, just kinda makes sense like the speed stir. No need to slow pour, then pour back etc. Just fill it and slide it, correct?

I started a thread awhile back (could-you-test-cya-in-complete-darkness-with-speedstir-light-t58833.html) about doing the testing using the speed stir with it's light in the dark. My reasoning is that, or a large artificial light in my house, would be the easiest to dublicate, so that lighting is taken out of the equation as it is constant test to test.

I've yet to re-test CYA, i will this weekend, outside sun to my back, and then i'm going to walk into the dark and use speedstir light and see what i get.

Yup mixing takes place in the 4088. Unfortunately, the 4088 tube doesn't fit in the spinstir. however, you should be able to do dilutions when necessary in the vial. I ordered a to 44ml vial to be able to do pH tests in it. I'm not sure the light in the spinstir will work with the 4088 at all. To my knowledge, the cya test is the only light needed test. I'm sure the experts here will correct me if I'm wrong. The light in the speedstir should help with most of the color tests though. Where the speed stir should really be helpful though is not having to put down the bottle of reagent between drops.

 

[YippeeSkippy]

Re: I developed an algae bloom for the third time this sprin

. Where the speed stir should really be helpful though is not having to put down the bottle of reagent between drops.

huh.
I must have been doing it differently than you do because (prior to getting my speedstir) I just held the vial in one hand swirling continuously while holding the reagent bottle in the other hand squeezing in the drops.