First Pool Test

wgoogs

Member
Jun 4, 2020
11
Austin, Texas
We purchased a home and are moving in tomorrow. I was able to go over and test the pool last night. Using a clorox strip everything was off the charts high for the most part. I then tried out my new K-2006 test kit testing only the FC. I lost track of the drops using the 25ml method and then tried again using the 10ml method. Once I got past 10ppm I just quit thinking the pool might be in shock. The kids actually jumped in for a few minutes while I was testing.

Today I went back for a full test.
FC - 18ppm
CC - 0ppm
pH - 7.6
Alk - between 175 and 200
CH - After 7 drops it went from red to clear but never turned blue. This calculated to about 175. Should I have kept adding more drops to wait for it to turn from clear to blue? Is there something else I need to do to get this test to work better? Maybe more indicator drops?
CYA - First pass was off the scale above 100. I diluted it 3x with distilled water and got a reading between 80 and 90. If I assume around 85 then we are at 255 on CYA.

Pool math says FC needs to be between 19 and 29 when CYA is this high. My CYA dilutions may not have been exactly accurate. The pool is currently being chlorinated by some tablets but I don't know what kind or how to know what kind. I was thinking of letting those finish out and then start using only liquid chlorine.

My first question. Does the CYA calculator really work at those high levels? Is the pool safe to swim at FC 18? The water looks perfect. The kids are going to want to swim on our first day in the new house. I know I need to start working on getting CYA down by draining and refilling. I need to research where to get the right pump for this. Does anyone have experience with swimming in pools with FC over 18 and CYA in the 200-300 range? I am also struggling to calculate the gallons for this pool. The shape is irregular, but I estimate somewhere around 16,500 to 17,000.

Any comments or advice is greatly appreciated.
 

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Texas Splash

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Welcome to TFP and having a new pool. :wave: My suggestion would be to do that water exchange as soon as you can. There's no sense trying to manipulate the FC at such high levels to compensate. It just makes things too difficult. Plus, with the FC that high, your pH will always be high as well. It's just not worth it. So once you get the keys to the house, start exchanging. You can buy or rent a decent sump pump from Home Depot or any such place. They also provide various sized hoses to help expedite the exchange. I don't think you have a high water table, but if in doubt, go slow and add water as you go or simply do exchanges in phases. Read the link below for more help. I suspect that once you do that exchange, all of your water parameters will start to look better. You might also try doing a CH test of your hose spigot water to get a feel for what to expect. Also try to add a little more details to your signature when you get a chance. See mine as an example. We'll watch for another set of test results once you get the water exchange complete. Congrats again! :swim:

 

wgoogs

Member
Jun 4, 2020
11
Austin, Texas
We are on an incline down to the lake. I am thinking of trying the water hose siphon method. Any concerns with that approach? I assume the water table is far below the pool given where we are relative to the lake, but was trying to decide if we should do simultaneous drain and refill or just drain followed by refill.
 

DeanP66

Well-known member
Mar 26, 2014
798
San Jose, CA
I would buy a submersible pump like this one:

Renting one will cost you more than half the cost of it and you might need it in the future if you need to drain again. You'll need to drain at the minimum 50% of your pool water and refill. More likely, closer to 75%. You just need to get your CYA down between 50 and 60 ppm.
 

wgoogs

Member
Jun 4, 2020
11
Austin, Texas
I have the pump. Planning to start drain and refill this week. I was reading up on SLAM, but that sounds like it was more necessary for pools that need to have the water cleared up. If my water is already clear, what is the best process once the pool is refilled? I want to make sure I have the right chemicals available and ready. I have liquid chlorine, but what else will typically be needed?

Thanks!
 

IceShadow

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TFP Guide
Jun 8, 2019
2,177
Milwaukee, WI
We are on an incline down to the lake. I am thinking of trying the water hose siphon method. Any concerns with that approach? I assume the water table is far below the pool given where we are relative to the lake, but was trying to decide if we should do simultaneous drain and refill or just drain followed by refill.
If you do a drain and refill, do it in the late afternoon and fill that night as much as you can. Then in the morning you'll need to have someone constantly keep the plaster wet and cool while you do the fill. You don't want the plaster cracking from baking in the sun....
I have the pump. Planning to start drain and refill this week. I was reading up on SLAM, but that sounds like it was more necessary for pools that need to have the water cleared up. If my water is already clear, what is the best process once the pool is refilled? I want to make sure I have the right chemicals available and ready. I have liquid chlorine, but what else will typically be needed?

Thanks!
On an ongoing basis, most pools need Liquid Chlorine and Muriatic Acid and that's it. Occassionally maybe you'll need some baking soda, soda ash, or borax to raise the TA or pH, but depending on your fill water and evaporation rate, your fill water might add all the TA you ever need.

Depending on your fill water you might also need to add some Calcium Chloride (CH increaser) to keep your CH up. Test your fill water and you'll know if you need that.

Finally you'll need some CYA in the pool if you go too low with the drain. Given that you have something like 270ppm of CYA you want to exchange about 85-90% of it to get down to 30-50ppm of CYA, so it might be easy to overshoot the exchange and end up with too low of CYA. Granular CYA is cheapest if you do need more, but that should be a very occasional thing.
 

wgoogs

Member
Jun 4, 2020
11
Austin, Texas
Thank you for all the advice. The Amazon pump with 1-1/4 pipe was able to get to 20gpm for draining the pool. Started around 1pm and finished at 1am. The refill with 3 hoses was only about 14gpm. Finished up around 4pm today. I tried to take out a little over 13,000 gallons from best I can tell is a 17,500 gallon pool. Here are the test results

FC 2
CC maybe 0.5 ( slightly off color and one drop cleared it up)
PH 7.4
TA 180
Ch 225
CYA 40 ( was closer to the 30 line)

So I added 2 quarts of LC to bring FC up to pool math level
Was thinking. Should I attempt to bring down TA or just leave it. Is it unusual to stay high in TA after replacing 85% of the water?
We have hard water, will CH come up on its own over time? Tap water was 110 CH
Should I bring CYA up? Dont want to go too high given how much of a pain it was to bring it down.

Also struggling to remove some nail rust stains from the construction crew next door. I feel like they shot 10 nails in the pool before we moved in. I did find one. I rubbed vitamin C tabs on them and finally just placed the tablets over the stains. They are lighter but not gone. I feel like I need to make a little container the shape of a nail stain to hold the tablets in place for a few hours.

Any advice is welcome. Will also update signature today. Pentair variable speed pump and sand filter. Need to get details. Also a polaris 2something cleaner.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Maybe try placing several crushed Vitamin C tabs in a thin sock or nylon and leaving it on the stain for a while. Things are getting warm in our area. A CYA of 40 is the lowest you want to be, and soon perhaps 50 if your pool gets full sun all day. But you can evaluate that as time goes on. If the pH isn't climbing too fast, you can just let the TA come down slowly on its own. That will also give the CH a little time to rise with evaporation and future top-offs. Stick close to the PoolMath APP for help or let us know if you have more questions.
 

wgoogs

Member
Jun 4, 2020
11
Austin, Texas
Maybe try placing several crushed Vitamin C tabs in a thin sock or nylon and leaving it on the stain for a while. Things are getting warm in our area. A CYA of 40 is the lowest you want to be, and soon perhaps 50 if your pool gets full sun all day. But you can evaluate that as time goes on. If the pH isn't climbing too fast, you can just let the TA come down slowly on its own. That will also give the CH a little time to rise with evaporation and future top-offs. Stick close to the PoolMath APP for help or let us know if you have more questions.
This morning FC is already down to 1ppm and CC may also be around 1ppm. I need to get the CYA up. Should I SLAM also due to CC at 1ppm? Is there a preferred order to SLAM and bringing up CYA? Thanks
I tested CYA and it was between 30 and 40 bu much closer to 30
 

wgoogs

Member
Jun 4, 2020
11
Austin, Texas
I decided not to do a SLAM. The CC almost seems like testing error for me. When I test FC I get from pink to clear, with possibly just a minor pink tint. As soon as I add the 5 drops of the CC test reagent the minor pink will get a little stronger. Then one drop of the FC titrant and it goes clear. I report that as 0.5CC. I have noticed if I give it one extra drop during the FC test to make sure it is very clear, that often the CC comes back clear without adding any drops of the FC titrant. Bottom line it seems like the CC is close to 0 or 0.5 most days. Sorry I couldn't remember the chemical names when I sat down at my computer.

I did go ahead and add CYA. I put it in a sock in the skimmer and left it overnight with pumps on 3000 rpm. The next morning the sock was still pretty full so I started to squeeze it until it was mostly empty. I immediately tested the CYA and it was at 60 (which worried me because I thought after the squeezing it was going to shoot it up to 100 after it had time to mix in. The next day when things settled down it was at 50. I guess my sample was near the skimmer with the sock during the squeezing and it picked up a little extra.

I have a 17,500 ish gallon pool. I have been adding per pool math about a quart of 10% LC in the morning and again at night to try and keep things stable. It seems to work pretty good at keeping the FC around 5.

I was curious on the pH. Every morning before adding any LC I test and see pH drifting up. It often hits 7.8 every day. I add about 35 oz of 31.45% Muriatic Acid each morning but don't test again afterwards. My TA is hanging around between 6 and 7 drops on the 10ml test, so 150 to 175. I can't tell if it is dropping or not.

Is it normal to have to add acid every day to keep pH at 7.4 or 7.6? Would having a high TA cause that problem? Should I try and drop pH to 7.2 to try and make the TA go down and stay down?

Is there any pros or cons to adding LC twice a day in smaller amounts vs one large add each morning? I felt like that would better mimic what the tablets were doing providing continuous chlorine.
 

Texas Splash

Mod Squad
TFP Expert
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For your TA test, you should be using a 25 ML water sample size, then after the drops you multiply by 10. So 7 drops would be a TA of 70. If you have the ability to add chlorine twice a day in smaller/consistent amounts, that's fine. At some point you shouldn't have to add acid everyday. The pH should stabilize. Check back with us after you re-calculate the TA based on the testing instructions I gave you and we'll look to see what may be increasing your pH so quickly.
 

wgoogs

Member
Jun 4, 2020
11
Austin, Texas
I am following the TA instructions using a 10ml sample that came with the kit which you multiply by 25. It should give a similar result to the 25ml version, but I will take a 25ml version after work today to get a little more accuracy. The 10ml version uses 1 drop of the first reagent and 3 drops of indicator I believe.
 

Texas Splash

Mod Squad
TFP Expert
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See Total Alkalinity - Trouble Free Pool. The 10 ML sample is only if someone expects their TA to be extremely high. Yours shouldn't fall in that category. If you still find that your TA is at 150 or more, it's time to lower it a bit. I'd lower the TA to about 80 or so and see if that helps reduce the pH increase.

 

duraleigh

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When I test FC I get from pink to clear, with possibly just a minor pink tint.
All the drops based tests we do count on a COMPLETE color change to finish the test. You continue to add drops until the last one you add results in NO FURTHER COLOR CHANGE. You then subtract that last drop from the total and the result is the end of your test.
 

wgoogs

Member
Jun 4, 2020
11
Austin, Texas
Thank you this is helpful. So when testing for CC, does it matter how much you overshoot on your FC drops? Will that extra drop on your FC test affect how many drops it takes on your CC test to change?

As for the TA, I have been thinking about how I might aerate the pool before committing to the big acid add to drop pH to 7.0.

Do you allow kids to swim in the pool at 7 or 7.2? I assume it is fine, but might cause some eye irritation if they open them underwater right?
 

duraleigh

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So when testing for CC, does it matter how much you overshoot on your FC drops? Will that extra drop on your FC test affect how many drops it takes on your CC test to change?
Good question! I don't know if that's ever been discussed. it makes sense to me that that confirming drop, since it's not counted in the FC test, has to be accounted for when you perform the cc's test.......meaning that you would start the CC's test with one drop already added.

I am not positive of that answer but my judgement says that's the way to look at it.
 

wgoogs

Member
Jun 4, 2020
11
Austin, Texas
I am an engineer. Hate to admit my chemistry is a little rusty for a chemical engineer, but I assume you are correct. So it is kind of important not to overshoot on the FC test, since your goal is to have a CC of 0 (requiring zero drops). If you overshoot, then you are either making it pass the CC test with zero by not counting that drop or possibly failing with a reading of 0.5 by counting that drop against your CC, when maybe it was only necessary for the FC. I suppose switching to the 25ml test could clear this up a bit, but that uses more test chemicals and takes longer.

It sounds like my TA is driving that constant pH increase I am battling based on the article and feedback on here. I wonder if my daily acid add will eventually bring it in, or if the larger acid add to take it down to 7.0 is necessary?
 

duraleigh

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Go ahead and lower your TA down to 60-80 but you can't do it with acid alone. Read the article in pool school
 

wgoogs

Member
Jun 4, 2020
11
Austin, Texas
Thank you. I have read it a few times. It says the acid alone drops the TA and then the aeration allows the pH to go back up so you can add more acid right? I was just wondering if by adding some acid every day to keep pH near 7.6 if the TA would eventually go down, but my understanding from your statement is that this will not work correct?