Proper Chemical Balance

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outdoor

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Jul 29, 2013
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OK so i'm new to pool ownership. Just had my new pool about 3 weeks

30' round above ground approx avg dept 4.5' so around 23800-24000 gallons.

Just picked up my TF100 test kit and ran all the tests since i previously only had the quick chlorine and pH dropper test that came with pool. Found it very difficult to read the colours on it.

It is SWG pool with Aquatrol system.

Here are my readings

FC 1.5
CC 0
TC 1.5
TA 170
Calcium 210
CYA ??? I filled tube up to the max before i could not see black dot

pH 7.5?? How can you more accuratlly measure this since sometimes it is difficult to distinguish the colours or tell which it is closer to?
Salt 3400
Temp 80

I too a sample to pool store last week they said everything was ok but I needed to add baking soda and Calcium to bring up TA and Calcium. It now appears TA is a bit too high??

Chlorine just yesterday was farly bright yellow on the cheap tester kit that came with the pool after I had run aqua trol on superchlorinate for 24 hrs since it appeared prior the chlorine was a bit low. Yesterday had about 8 people over for a swim and we were in and out of the pool for the afternoon.

Now Chlorine is a bit low?? is that normal? was not extremly hot or sunny day. have aquatrol set at 50% and am running pump usually on high from about 9am till 5pm (for solar Heat) then longer off solar heat for maybe another 4 hours.

suggestions??
 
Welcome to TFP.

Since your CYA is so low it's no wonder you're FC is low especially after that many people in the pool.

Don't worry about your TA as it'll come down by you adjusting the pH whenever it needs it.

I'd add some bleach in the pool to get to about 4 ppm FC. Then I'd get enough CYA to bring it to about 60 ppm and add that in a sock in front of a running return.
 
As to your comment about the ph and OTO colors hard to read, add an extra drop to both tests to improve the color. You are looking for the color, not the saturation of color. I find I like an extra drop in each. It makes no difference to the color, or accuracy of the test.
 
yes i wiped the dropper.

how or why would TA be lowered over time due to treating for rising pH? why would pH rise over time? I know several people who have salt water pools and say i'm worrying too much about all the levels, that they are able to just leave their machine run add CYA beginning of year, superchlorinate every now and then and all their levels are good.
 

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outdoor said:
yes i wiped the dropper.

how or why would TA be lowered over time due to treating for rising pH? why would pH rise over time? I know several people who have salt water pools and say i'm worrying too much about all the levels, that they are able to just leave their machine run add CYA beginning of year, superchlorinate every now and then and all their levels are good.
Click to expand...

pH rises over time due to outgassing of CO2 which is easily released from water. (the levels of CO2 in the water are dependent on temperature and surface agitation, (think warm shaken soda) cold water will hold more CO2 than warm water and CO2 tends to depress pH levels, so when it is released, pH rises.

Edit: to be more clear, surface agitation encourages the exchange of gasses which ordinarily couldn't break the surface tension of the water. Colder water won't release as much CO2 as warm water does, but us pool owners don't tend to swim in cold pools so under the conditions we maintain our pools, CO2 will outgass (be released) from the water.

Another thing that will effect pH is the bleach you have to add every day. Bleach has a high pH, so it will tend to elevate pH, we usually say it has no effect on pH because it degrades so fast, but over time it will raise the pH.
 
Hey man...

Listen to the experts on this site... They know EXACTLY what to do and how to do it. Follow their instructions step by step. They have guided me flawlessly from beginner to pretend-expert when it comes to chemistry. I read pool school countless times and use my TF-100 kit almost every day.

About your issue. My CYA was almost 0 at the beginning and my FC was swinging every direction. Now my CYA is 50-ish and my FC levels are more stable over time.

Also, as someone pointed out, SWG are good at maintaining the FC level, but suck at increasing it. They just aren't powerful enough. I always have a gallon or two of bleach handy and when FC gets down to 2.5 for whatever reason (like this am) I dump a quart of bleach and get to FC of 4 instantly.

Good luck!
 
ok since yesterday evening i did not have any bleach, i put the aquatrol on superchlorinate. Tested this morning and FC is up to 3.5. got a bit lower Alkalinity reading 150. Not sure if i'm doing this correctly. Instructions say add reagent till turns red, but it turns more of a pink??

going to bring a water sample to pool store double check my readings, pick up some CYA and bleach from grocery store for future use
 
outdoor said:
ok since yesterday evening i did not have any bleach, i put the aquatrol on superchlorinate. Tested this morning and FC is up to 3.5. got a bit lower Alkalinity reading 150. Not sure if i'm doing this correctly. Instructions say add reagent till turns red, but it turns more of a pink??

going to bring a water sample to pool store double check my readings, pick up some CYA and bleach from grocery store for future use
Click to expand...
Pink is the actual color. I don't know why they say red. You count drops while swirling until the last drop doesn't change the color. Then deduct that last drop. In your case, say it was greenish for the first 11 drops, then it went greyish, then pale pink, and then Barbie pink, and drop 16 didn't make the Barbie Pink any brighter. Deduct 16, you used 15 drops. TA = 150.

Don't bother having it rechecked by the pool store. They're more likely to be wrong than you are, and it will just confuse you.

Incidentally, TA really only matters to calculate the acid dose. High TA is only a problem if you're at risk of scaling due to high CH. Otherwise, just keep knocking it back to 7.2ish when it gets to 7.8ish and TA will naturally lower over time until your pool hits the sweet spot where pH stays stable for a week or so.
 
PridgNYC said:
Another thing that will effect pH is the bleach you have to add every day. Bleach has a high pH, so it will tend to elevate pH, we usually say it has no effect on pH because it degrades so fast, but over time it will raise the pH.
Click to expand...
It is the excess lye in bleach that contributes to a small rise in pH. Some bleach has more excess lye than others. Clorox tends to have the least. Same is true for chlorinating liquid -- it varies.

It is not true that the high pH of the bleach or chlorinating liquid makes the pH rise long-term nor do we say it has no effect because it degrades so fast, if you mean the concentrated product. The addition of bleach or chlorinating liquid has the pH rise, but the usage/consumption of that bleach has the pH drop back down because such usage/consumption is acidic and exactly counteracts the initial pH rise except for the excess lye (and chlorine outgassing which is usually negligible). See this post for technical details.

If one had 2 ppm FC per day added from bleach or chlorinating liquid and did not have the chlorine used/consumed or if that was not an acidic process, then the pH in a pool with 80 ppm TA would rise from 7.5 to a little over 8.3 in just one week. That simply doesn't happen in most pools. If the pH is rising in a pool, it is most likely to be from carbon dioxide outgassing and that can be minimized by having a lower Total Alkalinity (TA) level and reducing sources of aeration (waterfalls, spillovers, fountains, etc.). Other sources of pH rise include new plaster pools or re-plastered pools that are still curing.
 
You don't need to buy the liquid. The granular is just fine and a lot less expensive. Walmart even carries the granular.

Since you ahve an swg you need to ahve about 70 ppm CYA, not 30-50 ppm. You seriously need to wean yourself off the pool store. ;)
 
Use granular CYA found at Walmart, Lowes, Home Depot for a much cheaper price. You want to raise the CYA to 70-80, but shoot for adding 40 more for a total of 60 on your first dose. Add the CYA in a sock and place it over a return in the pool. Give a squeeze every now and then and it will dissolve in a day or two. You can measure it again in a week and then add more if needed.

Use the Pool Calculator to figure how much of each chemical to add, http://www.poolcalculator.com/.

Stay away from the pool store and trust your test results. Your tests will be more accurate and save you money.
 
ok added the liquid CYA, 3.79L yesterday evening. pump ran all evening and then till about 5am. tested water again

FC 4
pH 7.5
Ca 240
CYA 20

So it appears i need to get some granular CYA from Wallmart
 

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