First Time Pool Owner - Tired of the "Professionals" Giving Contradictory Information - Am I on the Right Track?

[sweetgerald]

Hi all - sorry if it's a long post.

Short background:
New house, first time pool owner. I'm the type that needs to know the details and maintenance consequences of everything I own. After moving in less than 3 months ago, I've started... diving in... on learning everything I can about pool chemistry. I have a comfortable understanding of relationships of pool properties and causes and effects of different chemical additions. I've lurked on the TFP threads (and learned passively) now long enough. Time for my first question(s).

Some more details:
Upon opening in early June, pool was very green. TA over 210, PH around 7.2 (I bought a Taylor K2005 test kit and have been using that ever since I moved in). Not a good place to start, and not sure how previous owners left it, but not good. Battled lowering TA and keeping PH from cratering for a period of a few weeks, aerating and adding dry acid. Have been using 73% cal hypo as primary chlorine source (recommended by my in-laws, only people close to me that have a pool). Previous owners most likely used trichlor tabs, as they were left behind, along with various fluff chemicals (clarifier, algaecides, and some PH up/down bags.

Pool specs

• located in PA
• Vinyl liner
• 18x36 "sport" pool (from what I've been told, that's the terminology). 3ft shallow on each end, extending about 10 ft from each end. From there, it slopes on all 4 sides, down to an area about 5ft 8in deep in the center.
• 3 suction lines (2 skimmer baskets, two main drain heads in deep center)
• 2 return jets
• Sand filter (model number not in my head)
• Hayward SP2670007X10 pump (installer said it's new as of last year or two)
• Heat Siphon digital heater
• Pool is in full sun all day, and it's been hot here, and seems to heat up very well on its own, when the solar cover is rolled across it

Most recent full test results

• FC 0 (this morning - 0 or trace amount, daily when tested)
• CC 0 (this morning - maybe trace amount, but less than 0.5 daily, when tested)
• PH 7.8
• TA 100
• CH 140
• CYA < 30 (was around 5 when I moved in, but have added some granular stabilizer, but not enough to get a reading on my test kit which starts at 30, but I think I'm close to mid to high 20s)

Chemicals I'm using/have used (I follow recommended instructions for usage on each container)

• cal hypo 73% (I might have used 40lb already in 2 months - seems excessive)
• dry acid (for lowering PH as needed)
• used a little PH up (is that sodium carbonate?) as needed while lowering TA
• granular stabilizer (about 3lb, total, I think)

First question - is my volume calculation correct?
Struggled at first to get the correct pool volume. After I tracked down the builder/installer, they told me 28,000 gallons. Seemed high. My own calculation comes in somewhere between 16,600 and 18,000, depending how I want to account for the angle of slopes from shallow to deep. Their declaration of 28,000 gallons would be for a 18x36x5.75 (assuming a uniform depth of 5.75, which... it is not). So I can't trust the guy that built it, apparently. Am I safe to just go with about 17,000 gallons for my volume for chemical calculations (I've been adding chemicals based on 16,600, which leads me to further questions).

Second question - I have been adding cal hypo, approximately 8oz per day (evenings), and it seems like I shouldn't need that much, that often. But, I'm new to this, so maybe it's the right amount. Is it reasonable that I should be adding a full 8oz daily?
I know TFP doesn't advocate for cal hypo, due to CH addition, but my CH started at 40 when we moved in. Very low CH in our water supply here, so I'm comfortable with adding the CH for a while, until I get near 200. This leads to next question.

Third question - I've been adding that much cal hypo every day, because my FC level never seems to hold. Overnight, I see losses of FC, which indicates that something organic is present. Water is clear. CC is 0 or less than 0.5 (according to my test kit) every morning. Daily, I see small amounts of what appears to me as dead algae (brownish powder, poofs when disturbed) settling on some vinyl wrinkles or a couple small areas where elevation changes in the slope and circulation can't keep it moving. I've been adding some chlorine also in the mornings, so sanitizer is in there for the family to swim. The OCLT would indicate that I need a SLAM - agree or disagree? The volume question above will help me determine proper volume calculation for liquid chlorine while SLAMming.
One of the suction lines (skimmer basket) has air suction at the elbow right before it gets into the pump. Installer advocated just closing that line, which I did for a while, when pool was still green. Not sure if that caused some sort of rooted algae problem in that line that keeps fueling daily growth and killing off. Since then, I've duct taped the elbow and opened the line. There is some miniscule air intake, still, which has attributed to PH raising slightly more over time, anecdotally, as compared to when I had it closed. I think I should keep it taped and open, until repaired, but if anyone disagrees, I'm happy to hear why. I'm hoping that being able to pass an OCLT (and meet all requirements to end the SLAM) will then allow me to gauge the daily needed dosage of chlorine, via either cal hypo or liquid chlorine.

TFP forums and pool school have been a huge help so far. Still a little overwhelming, learning how to maintain a pool while still settling in after a move, and getting ready for a second kid at the same time haha! Wife is not totally onboard with daily testing and keeping on the numbers. Her parents have a pool that's always visually clear, but they don't test and arbitrarily add cal hypo every couple days, and no other chemicals, so that's what my wife grew up with. Maybe they're lucky that they don't have visible water problems. I can't bring myself to do that. Haha. And knowing what I have learned reading here, I can now see why they have to do pump/equipment maintenance more often than I want to have to do it.

Thanks - sorry for the book.
Gerald

EDIT: forgot to ask - if something organic is consuming FC daily (overnight), should I expect CC to be greater than 0 or 0.5, as it seems to be each day? I've taken water sample to the pool store a couple times just for comparison, and their numbers are all actually pretty darn close to what I'm testing myself. I'm fairly confident in my own testing results, as they have been consistent and I am meticulous with what I'm doing. I'm confused about overnight FC loss, but not seeing a lot of CC (unless my daily cal hypo additions are also oxidizing the CC, but I'm not sure). Thanks!

 

[reggiehammond]

Hi there -

1) I also have a sport pool - was able to get the approximate level by length x width x average depth (deep - shallow).
2) TFP recommends liquid chlorine, muriatic acid and dry stabilizer. Those are the only items you need to maintain a TFP pool. You're on the merry-go-round of bad chemical ideas, it seems. You have a vinyl pool so CH is not a concern. You're adding dry acid to lower pH, but adding sulfates in the process. You're then undoing your work by adding sodium bicarb and raising TA, which causes pH drift. Trust me, it's much easier than what you're doing.
3) Your FC levels are not meeting criteria for a clean pool, full stop. You have algae wether you can see it or now, and need to do a SLAM. CC is an indicator of FC doing it's work, but FC level is a more important metric. Your FC at 0 is the BIGGER issue - FC should never fall below the minimum, even better the middle of the range. You also need more stabilizer - in full sun, your FC is getting eaten.

All that to say - you're not doing the TFP method. If you'll dump all of those habits and focus on the simple methods of TFP, I guarantee you'll have better results.
Lower pH to 7.2 with muriatic acid, raise CYA to at least 30ppm, then get on to SLAM levels with liquid chlorine. Test multiple times a day while in SLAM.

 

[sweetgerald]

Thanks for the reply.

1) I also have a sport pool - was able to get the approximate level by length x width x average depth (deep - shallow).

That's where my calculations came from. Thanks for giving me a sanity check on that.

2) TFP recommends liquid chlorine, muriatic acid and dry stabilizer. Those are the only items you need to maintain a TFP pool. You're on the merry-go-round of bad chemical ideas, it seems. You have a vinyl pool so CH is not a concern. You're adding dry acid to lower pH, but adding sulfates in the process. You're then undoing your work by adding sodium bicarb and raising TA, which causes pH drift.

I hear what you're saying, and want to get off that ride. I'm not married to anything I've done so far, as I'm still very much learning at this point. Just to clarify, only chemical I've routinely added in 2 months has been cal hypo, after adding dry stabilizer to bump up from 5 CYA. From a long thread I read on here today, it sounds like that's okay - chlorine is chlorine, regardless of delivery method, so long as I am aware of the CH as I use it, since I have some already. Only added the PH up (sodium carbonate) one time to bump PH marginally, after TA was sufficiently lowered into range using dry acid. I walked into a pool that had a very poor water balance, and needed some work. TFP site has been instrumental in understanding the why of it all.

The recommended-pool-chemicals page on here suggests that dry acid is fine to use in place of muriatric acid, for ease of handling. Is that still the case? Forgive me, not familiar with sulfates and what that can impact, if you don't mind my asking?

I was not aware that CH did not impact me with a vinyl liner, though I have read it is more important for other pool types. I thought the CH level had more to do with impact to equipment (filter pump, etc) though maybe I'm off base there, or that only applies to the high end of the CH scale? Thanks for the input.

3) Your FC levels are not meeting criteria for a clean pool, full stop. You have algae wether you can see it or now, and need to do a SLAM. CC is an indicator of FC doing it's work, but FC level is a more important metric. Your FC at 0 is the BIGGER issue - FC should never fall below the minimum, even better the middle of the range. You also need more stabilizer - in full sun, your FC is getting eaten.

That's what I suspected. Losing the FC overnight, after finding out about SLAM via this site, tipped me off to the need to SLAM. Just wanted confirmation that I was interpreting right. Despite clear water and no measured CC, the OCLT failure (i.e. waking up each day to 0 FC and remnants of dead algae) means it needs the SLAM.

After a proper SLAM, I should hopefully be able to more consistently manage the FC level, when it is not being consumed by unseen algae overnight. I'm prepping for the SLAM now. Thanks!

 

[Newdude]

Despite clear water and no measured CC, the OCLT failure (i.e. waking up each day to 0 FC and remnants of dead algae) means it needs the SLAM

Exactly. Only sun / UV and organics (algae/ swimmer residuals / etc) consume chlorine. The OCLT takes the sun out of the equation. If you lose FC in the dark, something is brewing and you need to SLAM.

Well done learning this far !!!

*also belated Welcome.

 

[red-beard]

On calculating the pool volume, I assume the pool is curved at the shallow ends. 18 feet across is 9 feet radius. Assuming a half circle at each end means a full circle 9 feet radius, = pi * r * r * depth = 3.1415 * 9 * 9 * 3 = 763.4 cu feet. Middle section = 18 x 18 x 3 = 972 cu feet. Deep part = inverse 4 sided pyramid. 18 x 18 base * depth / 4 = ( 18 x 18 x 2-2/3 ) /4 = 216 cu feet. Total = 1951.4 cu feet. 7.48051948 gallons per cu ft --> 14597.5 gallons. Call it 14,600 gallons. Add in the pool equipment, round it to 15,000 gallons.

On using Cal-Hypo, it is not the preferred method here, but it is not horrible. It causes a build up of Calcium hardness in the water, but it is not like too much CYA. Definitely do not use the dry acid. Really, not the right chemistry. Muriatic Acid is Hydrohchloric acid, and matches the chemistry of pools.

Like you, I bought a Taylor K2005. It is a good kit, but missing the most important test, the FAS-DPD. Pickup a Taylor K-1515A kit to get the test. You can't do a SLAM without this test. The chlorine level is above where you can read the level with the K2005 test.

Eventually you need to get to CYA 30. You are OK for now with 25-30. SLAM like it is 30 CYA = 12 FC.

Keep adding 5 FC each day. This is about 12-16 oz of Cal-hypo a day depending on the strength of the Cal-Hypo. It will also add about 3-3.5 ppm CH everyday at this level. LC (liquid chlorine) adds FC without anything else. If you can get Liquid Chlorine, you need to add 3 quarts per day.

Once you have the K-1515A test kit, raise the FC to 12 ppm to start the SLAM. Check a few times a day and add more LC to get yourself back to 12 PPM. Keep going with the SLAM unit you meet the three criteria. (Combined Chlorine 0.5 or less, Pass OCLT, Water is Clear).

SLAM - Shock Level and Maintain

We’ve all had to deal with a green pool. Clear algae from your pool with a SLAM! Read here to use shock level and maintain to clear your pool.

www.troublefreepool.com

 

[sweetgerald]

On calculating the pool volume, I assume the pool is curved at the shallow ends.

It is a full rectangle. 18x36. Small radius (less than 1 ft) in corners. I'm comfortable with volume calculation (big fan of mathematics haha), just making sure I'm not overthinking it somehow. And reconciling that against the installer saying it was 28,000 gallons. He's clearly incorrect and had me head-scratching for a hot minute.

Like you, I bought a Taylor K2005. It is a good kit, but missing the most important test, the FAS-DPD. Pickup a Taylor K-1515A kit to get the test. You can't do a SLAM without this test. The chlorine level is above where you can read the level with the K2005 test.

Curious, the K2005 has instructions to use a diluted sample, and multiply results in order to read higher FC levels, I think. I gather that is not reliable, or I might need to reread it? I do plan to get an FAS-DPD test as soon as possible anyway.

 

[sweetgerald]

Also, can anyone elaborate on the negative effects of dry acid? Or if it has been covered (I'm sure it has) I can dig deeper and find it myself. Sulfates were mentioned, but I can't say I'm familiar with what that means for the pool.

Thanks in advance and thanks to all who have chimed in.
Gerald

 

[Newdude]

Lifted from pool school:

Dry Acid​

Dry acid can be used to lower pH and TA. However dry acid contains sulfates which will accumulate in the water. Dry acid should not be used in plaster pools or pools with a SWG.

Dry acid is often sold as “pH Minus.”

Dry acid is sodium bisulfate. After dissociation of the acid salt, it leaves behind the sulfate ion.

Problems sulfates can cause include:

• Sulfates can damage concrete & plaster
• Excess sulfates in water increases the likelihood of corrosion on metal parts
• Excess sulfates in splash out water leads to degradation of any concrete surfaces
• Sulfates degrade the coatings on SWG plates
• At high enough concentrations, sulfates can react with calcium to form spindly, needle-like crystals of calcium sulfate (gypsum)
• While sulfates in vinyl pools is typically not as problematic as in plaster pools, scaling of gypsum crystals can increase the risk of liner puncture.[9]

Sulfates can only be removed by draining water.

Pentair specifically says on page 9 in the IntelliChlor SWG Manual[10] - CAUTION: The use of dry acid (sodium bisulfate) to adjust pool pH is discouraged especially in arid regions where pool water is subject to excessive evaporation and is not commonly diluted with fresh water. Dry acid can cause a buildup of by-products that can damage your chlorinator cell.

Dry acid should be considered only if obtaining muriatic acid is too expensive or difficult to obtain. In some countries, it’s illegal to sell it to the general public. It’s really not good to have in water.[11]

Dry acid can be used in hot tubs since it’s far easier to measure and dose small quantities of a granular substance and the water in a hot tub gets changed frequently. But, in a pool, it’s just not a good idea

 

[sweetgerald]

Any difference in the muriatic acid that is marketed for "pool use" vs "concrete/masonry solvent use"? Local Lowe's and Home Depot are out of stock of the Kem Tek brand marketed for pools. The other brand is Klean Strip marketed for concrete/masonry. Lowe's website says 31.45% but the bottle itself doesn't have any concentration on it, that I could see.

 

[Newdude]

I looked up the safety data sheet for the Lowe’s kind the other week for somebody else. If it says green/Eco/90% less fumes it’s half strength. But the data sheet listed it as a ‘trade secret’ guaranteeing 10%-30% strength.

Also found in said looking up was that the manufacturer only tested it for concrete use so they did not recommend it for pools. Typically in the paint aisle, they really don’t have much care to verify it for the few of us that know that MA is MA.

 

[sweetgerald]

I looked up the safety data sheet for the Lowe’s kind the other week for somebody else. If it says green/Eco/90% less fumes it’s half strength. But the data sheet listed it as a ‘trade secret’ guaranteeing 10%-30% strength.

Also found in said looking up was that the manufacturer only tested it for concrete use so they did not recommend it for pools. Typically in the paint aisle, they really don’t have much care to verify it for the few of us that know that MA is MA.

Lowe's had Klean Strip "Green" (Less Fumes! they claim) as well as just a Klean Strip variety.
So I am probably safe to assume that that the "non-Green" variety is still just straight up muriatic acid? Ironically, Lowe's lists it when searching under Outdoors/Pools/Pool Chemicals/Pool Balancing Chemicals/Muriatic Acid

Linked here (if I can post links):

https://www.lowes.com/pd/Klean-Strip-Klean-Strip-Muriatic-Acid-1-Gl/1002858920

Thanks Newdude, for following up. Boatloads of help, and greatly appreciated. I will be going the MA route, moving forward, but want to buy the right stuff.

 

[Newdude]

will be going the MA route, moving forward, but want to buy the right stuff

It’s all MA. Look for the buzz words for 14.x strength as opposed to 30.x % full strength. You’ll need twice as much of the half strength, but it won’t break the bank and it’s nicer to handle so there is that to consider as well.

 

[proavia]

Lowe's had Klean Strip "Green" (Less Fumes! they claim) as well as just a Klean Strip variety.
So I am probably safe to assume that that the "non-Green" variety is still just straight up muriatic acid? Ironically, Lowe's lists it when searching under Outdoors/Pools/Pool Chemicals/Pool Balancing Chemicals/Muriatic Acid

Linked here (if I can post links):

https://www.lowes.com/pd/Klean-Strip-Klean-Strip-Muriatic-Acid-1-Gl/1002858920

Thanks Newdude, for following up. Boatloads of help, and greatly appreciated. I will be going the MA route, moving forward, but want to buy the right stuff.

When going to the link you provided, it shows it as 31.45% and compatible with salt and chlorine pools.

Many times, the 14% percent low fume stuff is the same price as the 31.45% - so the overall cost winds up being twice as much for the same net effect on your pool.

 

[sweetgerald]

It’s all MA. Look for the buzz words for 14.x strength as opposed to 30.x % full strength. You’ll need twice as much of the half strength, but it won’t break the bank and it’s nicer to handle so there is that to consider as well.

My dude! Thanks.

Taylor K1515A is on 2 day shipping, to supplement the K2005 I already have. Will hit Lowe's for MA in the next day or so, and stop elsewhere for granular stabilizer. Probably SLAMming by end of week. I've got a half dozen gallons of 10% LC on standby.

PH is 7.4
CYA is 23

Will bump CYA nearer to 30, and give PH a very minor drop to 7.2 and go from there. Thanks.

Once complete... I think I've read this on the site elsewhere, but for a CYA of 25 - 30, where I'll be, a level of FC from 2 (minimum) to around 12 (SLAM) is comfortable for swimming, correct (via the chart)? With a target of somewhere between 4-6 as where I should shoot to keep it for the most part?

 

[sweetgerald]

When going to the link you provided, it shows it as 31.45% and compatible with salt and chlorine pools.

Hi proavia. Thanks for the reply.

Scrolling down toward the bottom, maybe 80% down, where the COMPARE area is, it has a red X icon for pool compatibility. Other brands in the compare are "compatible" but it appears this brand did not test for use on pools and doesn't want to label it as such, according to answered questions.

Under the SPECIFICATIONS heading, I initially thought the X there meant yes - compatible, but the branding is I guess saying otherwise?

That's what gave me pause initially when looking at it.

 

[Newdude]

I think I've read this on the site elsewhere, but for a CYA of 25 - 30, where I'll be, a level of FC from 2 (minimum) to around 12 (SLAM)

Yes. SLAM is 40% FC of CYA. But you can’t read in between the 10s like it appears to the eyes. So we round up to 30 when it’s 23/25/ etc. as long as it’s definitely not 20, it’s 30.

Swimming is fine between minimum and SLaM but you need to see bottom in case you have to find a disabled swimmer. It would be a rare occurrence but we are nothing without safety.

Also, until you are super in tune with your pool, keep target as your ‘minimum’ when things are good after the SLAM. You can ride the line as close as you wish once you are your own pro. Many of us kept aiming a bit high even once we knew everything we needed to know. When life pulls you away for a day, or an event happens like a extra hot day, you’re covered. Pick up tomorrow like nothing happened.

 

[johngault007]

Lowe's had Klean Strip "Green" (Less Fumes! they claim) as well as just a Klean Strip variety.
So I am probably safe to assume that that the "non-Green" variety is still just straight up muriatic acid? Ironically, Lowe's lists it when searching under Outdoors/Pools/Pool Chemicals/Pool Balancing Chemicals/Muriatic Acid

Linked here (if I can post links):

https://www.lowes.com/pd/Klean-Strip-Klean-Strip-Muriatic-Acid-1-Gl/1002858920

Thanks Newdude, for following up. Boatloads of help, and greatly appreciated. I will be going the MA route, moving forward, but want to buy the right stuff.

I have an Ace Hardware about 5 minutes from the house, and believe it or not, their MA is a bit cheaper than Lowe's right now. It's Transchem brand at 31.45% and it works well. I just have to remember to hold my breath or pour upwind when using it.

Although not branded for pool use, I have also taken the guidance here at TFP and use the above mentioned MA and have great results.

Transchem Muriatic Acid 1 gal Liquid - Ace Hardware

Professional Strength 31.45% HCL (Muriatic Acid), excellent for pH reduction in swimming pools or to clean and etch masonry surfaces, excellent for pH reduction in all commercial and residential pools.Find the ACID MURIATIC GAL at Ace.

www.acehardware.com

 

[Newdude]

*also Gerald, when the time comes, MA is totally fine to eyeball. Normally poolmath zeros us in to the last drop, but it’s really not needed here with 10s of thousands of gallons. If you’re 2 cups over/under with a guess, it’s way close enough and no need to risk spillage measuring it out.

 

[sweetgerald]

It's Transchem brand at 31.45%

Thanks @johngault007! Looking at your link, their bottle does mention pH control for swimming pools in the fine print on back and bottom of bottle (online pic). It's about $1 less than the Lowe's equivalent, too. I suppose I can drive 1 mile further to get to nearest Ace

@Newdude Yes - with regard to swimming safety, point taken - within FC range and clear to see bottom of deep area, without a doubt. With regard to min FC, that's what I was thinking. Even if 2 is min for 30 CYA, I'll be striving to hold at least 4, so I have a sanitization buffer if needed for a day.

 

[Newdude]

Even if 2 is min for 30 CYA, I'll be striving to hold at least 4, so I have a sanitization buffer if needed for a day.

The average pool consumes 2-4ppm daily. Your UV demand isn’t the highest in PA, but it’s still the peak season so right now you are probably closer to 4 than 2. Maybe even more than 4 with hot days and lots of swimmers once you’re clear.

I would shoot for 6 at a minimum to give yourself a 24 hour window more or less garaunteed. I’d go 8-10 to double that. There is tons of leeway above and nothing but pea soup if you go below. Food for thought.