Nasty algae in pool. HELP!

[morteney]

Hello. I'm a first time pool owner, and I have an above ground 15 ft x 48 inch swimming pool. I was out of town about a month ago for a week, and my lawn person unplugged the pool while mowing, and it stayed unplugged for about a week and when I returned home my pool was green and disgusting.

Since then, I shocked it and it was back to somewhat normal levels, then a few days later turned green.
I tried using the algaecide, didn't help.
I've also tried the clarifier, and that didn't help either.
We were out of town for a few more days here recently, and when I returned, the pool looked like a black lagoon. You could see the bottom of the pool but it was green, and you could see the algae growing all over the liner and steps.
I asked a few people for help, and they recommended using bleach. I poured about 5 gallons of bleach in the pool this morning, and the pool water is already clear, and you can tell that the algae is starting to kind of break down, but I am unsure of what my next step should be.

I realize I am a complete newb when it comes to pool care, so that's why I found this forum.

When I tested the pool, these were the levels.

TH : 100
FC: 10/20
pH: 8.4
TA: 180
CYA: 100

I am also attaching some pics of the pool to give you guys a better idea of what a mess I am dealing with.

http://i222.photobucket.com/albums/dd29 ... one023.jpg
http://i222.photobucket.com/albums/dd29 ... one022.jpg
http://i222.photobucket.com/albums/dd29 ... one021.jpg
http://i222.photobucket.com/albums/dd29 ... one020.jpg

[floridapooltech]

Hello. I'm a first time pool owner, and I have an above ground 15 ft x 48 inch swimming pool. I was out of town about a month ago for a week, and my lawn person unplugged the pool while mowing, and it stayed unplugged for about a week and when I returned home my pool was green and disgusting.

Since then, I shocked it and it was back to somewhat normal levels, then a few days later turned green.
I tried using the algaecide, didn't help.
I've also tried the clarifier, and that didn't help either.
We were out of town for a few more days here recently, and when I returned, the pool looked like a black lagoon. You could see the bottom of the pool but it was green, and you could see the algae growing all over the liner and steps.
I asked a few people for help, and they recommended using bleach. I poured about 5 gallons of bleach in the pool this morning, and the pool water is already clear, and you can tell that the algae is starting to kind of break down, but I am unsure of what my next step should be.

I realize I am a complete newb when it comes to pool care, so that's why I found this forum.

When I tested the pool, these were the levels.

TH : 100
FC: 10/20
pH: 8.4
TA: 180
CYA: 100

I am also attaching some pics of the pool to give you guys a better idea of what a mess I am dealing with.

http://i222.photobucket.com/albums/dd29 ... one023.jpg
http://i222.photobucket.com/albums/dd29 ... one022.jpg
http://i222.photobucket.com/albums/dd29 ... one021.jpg
http://i222.photobucket.com/albums/dd29 ... one020.jpg

Well, to start off with, you will need:

-126 oz. Calcium Chloride to bring your Calcium hardness (TH) back up to an acceptable level (260ppm)
-Free chlorine should be fine as a shock level, but after the algae is completely gone, it needs to be dropped back to around 3ppm.
-39 oz. of Muriatic acid to bring your pH & Alkalinity down (likely cause of your algae problem) (7.6pH/100TA)
-CYA is acceptable, but use "acceptable" at your own risk. The higher the CYA, the more FC you will need in order to effectively "sanitize" AKA kill off algae. Too low, however, you will see your FC depleted by the end of the day due to the sun. The ideal range would be 30-50ppm CYA. Before adding these chemicals, be sure to brush the floor/walls of the pool. After adding them, make sure your pool pump is running non-stop (very important) until all the algae is gone, and the water is crystal clear! Maintain clear water by running your pump min. 8 hours per day. Hope all this helps and following those dosages, you should have a crystal clear pool this weekend!

[floridapooltech]

Forgot to mention...Your high CYA levels are due to adding either too much conditioner/stabilizer, or you are sanitizing your pool with only trichlor tablets or dychlor granular. It would be recommended that for the remainder of the season, you use only liquid chlorine/bleach and no more tabs or granular in the floater/chemical feeder so your CYA can come back to normal levels without having to dump water and replace with fresh.

[morteney]

Thank you so much for your help!
Can I find these chemicals at Wal Mart or will I need to go to a pool chemical supply store?
Also, if I continue to use bleach rather than the floating tablets, how often do you think I will need to add bleach in the water?
And, will the chemicals eat away the algae that is in the pool currently, or will I have to skim it all out?
Again, thank you so much for your help!

[floridapooltech]

Thank you so much for your help!
Can I find these chemicals at Wal Mart or will I need to go to a pool chemical supply store?
Also, if I continue to use bleach rather than the floating tablets, how often do you think I will need to add bleach in the water?
And, will the chemicals eat away the algae that is in the pool currently, or will I have to skim it all out?
Again, thank you so much for your help!

I don't believe you can find muriatic acid or calcium chloride at walmart, however, the chlorine bleach you get at walmart isn't as fresh as you would get at your pool store as its been sitting in their warehouse, and stores for "x" amount of time under those fluorescent lights 24 hours a day since they were packaged. fluorescent lights produce UV, which breaks down chlorine, hence the chlorine will not be as potent as you would find at the pool store (pool stores also have a stronger chlorine to start off with too). You will most likely be adding about 1.25 gallons of chlorine at 12-15% per week. You may have to add about a cup of muriatic acid once a month or so since chlorine is high in pH. The dead algae that will be in the bottom of your pool needs to be vacuumed to filter. It may be a good ideal to get an automatic pool cleaner if you don't want to vacuum your pool once a week (should be brushing it too). Automatic pool cleaners for above ground pools start as little as $150 HERE.

After the pool is clear, you will need to backwash your filter if it is sand or D.E., or clean the filter element if you have a cartridge. If you maintain the 4 most important levels in your pool, (pH, TA, FC, CYA) & run your pool pump atleast 8 hours a day, you shouldn't have any more of these algal outbreaks! Hope you have a great remainder of your swimming season!!

[chem geek]

I don't believe you can find muriatic acid or calcium chloride at walmart, however, the chlorine bleach you get at walmart isn't as fresh as you would get at your pool store as its been sitting in their warehouse, and stores for "x" amount of time under those fluorescent lights 24 hours a day since they were packaged. fluorescent lights produce UV, which breaks down chlorine, hence the chlorine will not be as potent as you would find at the pool store (pool stores also have a stronger chlorine to start off with too).

Though I get 12.5% chlorinating liquid from my pool store, there are a lot of people who use 6% bleach from Wal-Mart without any problems. Their turnover is usually pretty good and 6% bleach does not degrade nearly as quickly as chlorinating liquid (half-life is around 4 times longer for bleach as shown in the table at the bottom of this page). The UV from fluorescent lights isn't very strong -- the internal UV hits phosphors on the tube that convert it to visible light and you don't get suntanned under a standard non-tanning fluorescent light (see this link) and the bottles of bleach are mostly opaque.

The following are some chemical equivalents to common products found in pool stores:

pH Up -- identical to Arm & Hammer Super Washing Soda (careful: NOT the laundry detergent) -- sodium carbonate

Alkalinity Up -- identical to Arm & Hammer Baking Soda -- sodium bicarbonate

6% Unscented Bleach -- the same as chlorinating liquid except at lower strength -- sodium hypochlorite

Calcium Hardness Increaser -- same as Peladow, Dowflake, Tetra de-icers -- calcium chloride (anhydrous or dihydrate)

Muriatic Acid -- may be found in hardware and big-box stores; read the label as some is half-strength which may fume less but may not be priced half as much

One can also use 20 Mule Team Borax instead of pH Up to raise the pH with only half the rise in Total Alkalinity (TA). Note also that not all bleach is the same -- off-brand regular bleaches are often 3% or less in strength. Off-brand Ultra bleaches are usually 6% as is Clorox Regular (Ultra in Canada). Also note that Clorox brand has the lowest pH at around 11.9 with the lowest amount of excess lye (around 0.06%) while off-brands often have higher pH at around 12.5 or higher and much more excess lye (around 0.25% or higher). Good 12.5% chlorinating liquid has a pH of around 12.5 (were it not for the excess lye, the pH would be around 10.6-10.7) while some brands of chlorinating liquid have a pH of 13.0 or higher.

You will most likely be adding about 1.25 gallons of chlorine at 12-15% per week. You may have to add about a cup of muriatic acid once a month or so since chlorine is high in pH.

As for maintaining pH, one can minimize the amount of acid that needs to be added when using a hypochorite source of chlorine (bleach, chlorinating liquid, Cal-Hypo, lithium hypochorite) by maintaining a lower Total Alkalinity (TA). Most of the rise in pH comes from the outgassing of carbon dioxide and this is accelerated when the TA is higher. The following gives the amount of acid needed to compensate for the excess lye in bleach and chlorinating liquid. Note that the consumption/usage of chlorine is acidic so the high pH from the hypochlorite itself is irrelevant and were it not for the excess lye, these sources of chlorine would be net pH neutral when accounting for consumption/usage.

One gallon of 12.5% chlorinating liquid at a pH of 12.5 needs a little less than 1 fluid ounce of full-strength Muriatic Acid (31.45% Hydrochloric Acid) to compensate for pH. However, if the pH of the chlorinating liquid is 13.0, then somewhat more than 2-1/2 fluid ounces is needed. If the pH is 13.5, then closer to 10 fluid ounces is needed. So the pH of bleach or chlorinating liquid product makes a big difference though the bulk of pH rise is still normally associated with TA.

Richard

[duraleigh]

There is no need for Calcium in a vinyl pool. You can disregard it.

Your most important first step is to lower your pH using muriatic acid down to around 7.2.

Secondly, I would consider getting a good drops based test kit. YOur results appear as if they are coming from test strips and I would not trust them at all....especially on CYA results. If you choose not to get your own kit, get a pool store to test for you and post those results.

Be prepared to shock your pool with Clorox. It will be crystal clear once you kill the algae.

[floridapooltech]

There is no need for Calcium in a vinyl pool. You can disregard it.

Your most important first step is to lower your pH using muriatic acid down to around 7.2.

Secondly, I would consider getting a good drops based test kit. YOur results appear as if they are coming from test strips and I would not trust them at all....especially on CYA results. If you choose not to get your own kit, get a pool store to test for you and post those results.

Be prepared to shock your pool with Clorox. It will be crystal clear wants you kill the algae.

You are right, I didn't even think about it being vinyl. glad you caught it! There are test strips that can be trusted such as the "AquaChek" line. But the ones you buy at Walmart or a few other stores are just about useless as you said.

You should be fine only getting a gallon of muriatic acid (about $4.00) at your local pool store. It will last you awhile. Disregard what Chem Geek is mentioning about the pH up because you are actually trying to bring your pH DOWN. This is only going to be confusing right now. Though when the time is right, those are items to think about.

[chem geek]

There are test strips that can be trusted such as the "AquaChek" line. But the ones you buy at Walmart or a few other stores are just about useless as you said.

No test strips test for Calcium Hardness (CH) -- they only test Total Hardness (TH) which includes magnesium. This doesn't matter in this situation for a vinyl pool. The CYA test seems to be the most flaky with test strips -- not sure how AquaChek does in this regard, but know that the accuracy and precision of all the tests is a lot more approximate. The following compares the 4-way AquaCheck Yellow and the 7-way AquaChek Select test strips vs. the Taylor K-2006 or TF-100 (and similar) test kits:

........... AquaChek Yellow .................. Taylor K-2006 ................ TFTestkits TF-100
pH ... 6.2, 6.8, 7.2, 7.8, 8.4 ......... 7.0, 7.2, 7.4, 7.6, 7.8, 8.0 ... 6.8, 7.2, 7.5, 7.8, 8.2
FC ... 0, 0.5, 1.0, 3.0, 5.0, 10.0 ... every 0.2 or 0.5 up to 50 .... every 0.2 or 0.5 up to 50
TA ... 0, 40, 80, 120, 180, 240 .... every 10 ppm with no limit .. every 10 ppm with no limit
CYA ... 0, 30-50, 100, 150, 300 ... every 10 ppm from 0-100 ... every 10 ppm from 0-100

............. AquaChek Select ................... Taylor K-2006 ................. TFTestkits TF-100
TH ..... 0, 100, 250, 500, 1000 ...... not available nor relevant ..... not available nor relevant
CH ......... not available ................. every 10 ppm with no limit ..... every 10 ppm with no limit
TC ... 0, 0.5, 1.0, 3.0, 5.0, 10.0 ... every 0.2 or 0.5 up to 50 ...... every 0.2 or 0.5 up to 50
FC ... 0, 0.5, 1.0, 3.0, 5.0, 10.0 ... every 0.2 or 0.5 up to 50 ...... every 0.2 or 0.5 up to 50
pH ... 6.2, 6.8, 7.2, 7.8, 8.4 ......... 7.0, 7.2, 7.4, 7.6, 7.8, 8.0 .... 6.8, 7.2, 7.5, 7.8, 8.2
TA ... 0, 40, 80, 120, 180, 240 .... every 10 ppm with no limit .. every 10 ppm with no limit
CYA ... 0, 30-50, 100, 150, 300 ... every 10 ppm from 0-100 ... every 10 ppm from 0-100

You can see images of the back of the AquaChek bottle for AquaChek Yellow and AquaChek Select to see how the color matching would work. With the Taylor and TFTestkits FAS-DPD chlorine tests, you count the drops until the sample turns clear as shown in this demo.

If I assume that the test strip accuracy has one choose one of the patches as shown on the bottle, then in the range of normal pool values this is +/- 0.4 in pH, +/- 40 ppm in TA, +/- 150 (or 250 ppm) TH which would can result in a saturation index error of nearly 1.0 which is very high and, of course, there is no CH measurement. So this is definitely not suitable for plaster pools though might be OK for some vinyl pools such as small Intex Easy-Set pools that one dumps/refills every season. This is consistent with the recommendations in the Pool School at Trouble Free Pools.

[floridapooltech]

There are test strips that can be trusted such as the "AquaChek" line. But the ones you buy at Walmart or a few other stores are just about useless as you said.

No test strips test for Calcium Hardness (CH) -- they only test Total Hardness (TH) which includes magnesium. This doesn't matter in this situation for a vinyl pool. The CYA test seems to be the most flaky with test strips -- not sure how AquaChek does in this regard, but know that the accuracy and precision of all the tests is a lot more approximate. The following compares the 4-way AquaCheck Yellow test strips vs. the Taylor K-2006 or TF-100 (and similar) test kits:

........... AquaChek Yellow .................... Taylor K-2006 ................. TFTestkits TF-100
pH ... 6.2, 6.8, 7.2, 7.8, 8.4 ......... 7.0, 7.2, 7.4, 7.6, 7.8, 8.0 ... 6.8, 7.2, 7.5, 7.8, 8.2
FC ... 0, 0.5, 1.0, 3.0, 5.0, 10.0 ... every 0.2 or 0.5 up to 50 .... every 0.2 or 0.5 up to 50
TA ... 0, 40, 80, 120, 180, 240 .... every 10 ppm with no limit .. every 10 ppm with no limit
CYA ... 0, 30-50, 100, 150, 300 ... every 10 ppm from 0-100 ... every 10 ppm from 0-100

You can see images of the back of the AquaChek bottle here to see how the color matching would work. With the Taylor and TFTestkits FAS-DPD chlorine tests, you count the drops until the sample turns clear as shown in this demo.

DPD kits are definitely the best to use, however, they sometimes require a certain technique to get any accuracy. The AquaChek 7 is the best to go with if you were to use the strips at all, as they are fairly accurate. You are correct on the CYA scale, however, as long as you are in the 30-50 range (up to 100 if you really want to be), you don't really need to be THAT accurate, and they realize that hence not giving every 10ppm increments.

[chem geek]

DPD kits are definitely the best to use, however, they sometimes require a certain technique to get any accuracy. The AquaChek 7 is the best to go with if you were to use the strips at all, as they are fairly accurate. You are correct on the CYA scale, however, as long as you are in the 30-50 range (up to 100 if you really want to be), you don't really need to be THAT accurate, and they realize that hence not giving every 10ppm increments.

FAS-DPD and DPD are not the same thing. I agree that DPD can be tricky to get accuracy since it's a color-matching exercise, but that's not the chlorine test I'm talking about. Look at the demo link I gave for the FAS-DPD chlorine test to see that there is no color-matching required. It's a "count the drops" until the sample turns from pink/red to clear test -- very easy to do even if one is color-blind and it's very accurate. Getting either the Taylor K-2006 or the TF-100 is a huge step up from test strips and even other drop-based kits. A comparison of these two kits is described here. (I also added the 7-way AquaChek Select to my previous post, but that still doesn't help.)

Because the amount of Free Chlorine (FC) needed to prevent algae is dependent on the Cyanuric Acid (CYA) level as shown in the Chlorine / CYA Chart, it is important to have the CYA be reasonably accurate. There's a big difference between 30 ppm, 60 ppm, and 100 ppm since 100 ppm requires over 3 times the FC level to prevent algae compared to 30 ppm.