First Water Chemistry Test Advice

rcasper05

Member
Feb 18, 2025
9
Charleston,SC
Pool Size
9150
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-3)
Hey all, I just moved into a house with a 1 year old 9.2k gallon fiberglass pool that has a Tristar VS900 pump and a TCells315 SWG with a panel I can raise and lower Chlorination % on (not sure if all the details matter, but I figured something may help).
The old owners got weekly servicing, balancing, and cleaning done - but I’m not sure when that ended between us going under contract a month ago and now. I plan on saving the $275 companies charge around me for weekly service and trying to maintain it myself. I did have a company come in for an inspection and quote and they said everything looked good. We are in South Carolina so the pool didn’t get winterized, and I want to have it swim ready for the warm weather soon.
I bought a Taylor K-2006 Salt test kit and tested the water today. The results are below. After plugging them into Pool Math I was a bit worried about some things. Where should I begin with the Alk, Calcium Hardness, and CYA coming in low to the target and the Free Chlorine coming in way higher than the target?
PH 7.5
Alkalinity 50
Calcium Hardness 130
CYA 50
Free Chlorine 8 (Worried me, not sure if I should retest since it was the first I’ve ran with the kit)
Salt 3400

Thanks for any advice!
 
Hey rcasper and Welcome !!!! :wave:

For inheriting somebody else's chemical stew, you are sitting PRETTY.

I was a bit worried about some things
No more. Absolutely none of that. Come tell us what things are, and ask if you should step in or let it ride.

TA of 50+ is fine and it helps keep the PH from rising. Imagine the two are rubber banded together. TA will pull Ph with it, and with Ph wanting to naturally rise, a slightly lower Ph combats that. We usually shoot for 60, but if it settles at 50 it's close enough for government work.

Calcium will only matter for you with a gas heater. And it still dosent matter, but it does for the warranty because the industry says it does. (Really outdated thoughts there...... steam boilers in the early 1900s and such, where it did matter)
Free Chlorine 8 (Worried me
Here's the deal. Minimum FC is Swampville. It's not absolute, but it's a chance. The more chances you make, the more chance you have to visit Swampville.

Everyday the sun burns off FC. As it gets warmer (higher sun angle/ more daylight) it will burn more per day. Then it gently falls through the fall back to very little for the winter. A big storm or swim day may also consume some FC, although likely not as much as the UV/sun.

Your mission, is to remain free and clear above min FC per your CYA. Loosing 1 ppm per day right now ? Then an 7 is a couple days supply at 50 CYA. In July you might lose 4ppm a day and a 7 is barely gonna cut it.

swcg_chart.jpg

You adjust the cell runtime (%) or the hours of said % to make more or less FC to match the loss of that part of the season. Plus a little wiggle room for a particularly high UV day or big storm out of the blue.

24 hours at 25% = 6 hours producing
12 hours at 50% = 6 hours producing
6 hours at 100% = 6 hours producing.

Math at will, it's all the same.

An Aquarite T3 cell will make 1 FC about every 4 hours for you. Again, math at will with hours or % when you need 3ppm a day. (Etc). In the above examples, 6 hours producing will make about 1.5 ppm per day, probably about right for right now.

Click on the below links to dive further.

Pool Care Basics
FC/CYA Levels
 
Last edited:
50 CYA for now is plenty but come the hotter temps 70 should be your minimum. 5-10 would be the target and being on the high side of target is to your advantage of never flirting with minimums and algae. You need to get to know the pool and it's loses for the hot season and remain in higher target as a high bather load can turn things upside down. Testing here is key and you're off to a good start.
 
Hey rcasper and Welcome !!!! :wave:

For inheriting somebody else's chemical stew, you are sitting PRETTY.


No more. Absolutely none of that. Come tell us what things are, and ask if you should step in or let it ride.

TA of 50+ is fine and it helps keep the PH from rising. Imagine the two are rubber banded together. TA will pull Ph with it, and with Ph wanting to naturally rise, a slightly lower Ph combats that. We usually shoot for 60, but if it settles at 50 it's close enough for government work.

Calcium will only matter for you with a gas heater. And it still dosent matter, but it does for the warranty because the industry says it does. (Really outdated thoughts there...... steam boilers in the early 1900s and such, where it did matter)

Here's the deal. Minimum FC is Swampville. It's not absolute, but it's a chance. The more chances you make, the more chance you have to visit Swampville.

Everyday the sun burns off FC. As it gets warmer (higher sun angle/ more daylight) it will burn more per day. Then it gently falls through the fall back to very little for the winter. A big storm or swim day may also consume some FC, although likely not as much as the UV/sun.

Your mission, is to remain free and clear above min FC per your CYA. Loosing 1 ppm per day right now ? Then an 7 is a couple days supply at 50 CYA. In July you might lose 4ppm a day and a 7 is barely gonna cut it.

View attachment 629410
Hey rcasper and Welcome !!!! :wave:

For inheriting somebody else's chemical stew, you are sitting PRETTY.


No more. Absolutely none of that. Come tell us what things are, and ask if you should step in or let it ride.

TA of 50+ is fine and it helps keep the PH from rising. Imagine the two are rubber banded together. TA will pull Ph with it, and with Ph wanting to naturally rise, a slightly lower Ph combats that. We usually shoot for 60, but if it settles at 50 it's close enough for government work.

Calcium will only matter for you with a gas heater. And it still dosent matter, but it does for the warranty because the industry says it does. (Really outdated thoughts there...... steam boilers in the early 1900s and such, where it did matter)

Here's the deal. Minimum FC is Swampville. It's not absolute, but it's a chance. The more chances you make, the more chance you have to visit Swampville.

Everyday the sun burns off FC. As it gets warmer (higher sun angle/ more daylight) it will burn more per day. Then it gently falls through the fall back to very little for the winter. A big storm or swim day may also consume some FC, although likely not as much as the UV/sun.

Your mission, is to remain free and clear above min FC per your CYA. Loosing 1 ppm per day right now ? Then an 7 is a couple days supply at 50 CYA. In July you might lose 4ppm a day and a 7 is barely gonna cut it.

View attachment 629410

You adjust the cell runtime (%) or the hours of said % to make more or less FC to match the loss of that part of the season. Plus a little wiggle room for a particularly high UV day or big storm out of the blue.

24 hours at 25% = 6 hours producing
12 hours at 50% = 6 hours producing
6 hours at 100% = 6 hours producing.

Math at will, it's all the same.

An Aquarite T3 cell will make 1 FC about every 4 hours for you. Again, math at will with hours or % when you need 3ppm a day. (Etc). In the above examples, 6 hours producing will make about 1.5 ppm per day, probably about right for right now.

Click on the below links to dive further.

Pool Care Basics
FC/CYA Levels


You adjust the cell runtime (%) or the hours of said % to make more or less FC to match the loss of that part of the season. Plus a little wiggle room for a particularly high UV day or big storm out of the blue.

24 hours at 25% = 6 hours producing
12 hours at 50% = 6 hours producing
6 hours at 100% = 6 hours producing.

Math at will, it's all the same.

An Aquarite T3 cell will make 1 FC about every 4 hours for you. Again, math at will with hours or % when you need 3ppm a day. (Etc). In the above examples, 6 hours producing will make about 1.5 ppm per day, probably about right for right now.

Click on the below links to dive further.

Pool Care Basics
FC/CYA Levels
Thank you! This was all really helpful information, and I appreciate you giving me a lot of peace of mind here. This also answers some questions I've had about how long I should be running the pump for, and at what %.
 
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50 CYA for now is plenty but come the hotter temps 70 should be your minimum. 5-10 would be the target and being on the high side of target is to your advantage of never flirting with minimums and algae. You need to get to know the pool and it's loses for the hot season and remain in higher target as a high bather load can turn things upside down. Testing here is key and you're off to a good start.
Awesome, thank you. Any advice on liquid vs dry stabilizer, and the best method to add it when the time comes?
 
Any advice on liquid vs dry stabilizer
Liquid clumps at the bottom and is nearly impossible to get a partial dose correctly no matter how much you shake it. When needing a full jug, you can rinse it several times to get it all out.

Liquid is also usually more expensive. I like (powder) puritech stabilizer/conditioner from amazon.


best method to add it when the time comes?
I have a big pool but this can be scaled down with a tied up sock or such for smaller batches.

 
Hey rcasper and Welcome !!!! :wave:

For inheriting somebody else's chemical stew, you are sitting PRETTY.


No more. Absolutely none of that. Come tell us what things are, and ask if you should step in or let it ride.

TA of 50+ is fine and it helps keep the PH from rising. Imagine the two are rubber banded together. TA will pull Ph with it, and with Ph wanting to naturally rise, a slightly lower Ph combats that. We usually shoot for 60, but if it settles at 50 it's close enough for government work.

Calcium will only matter for you with a gas heater. And it still dosent matter, but it does for the warranty because the industry says it does. (Really outdated thoughts there...... steam boilers in the early 1900s and such, where it did matter)

Here's the deal. Minimum FC is Swampville. It's not absolute, but it's a chance. The more chances you make, the more chance you have to visit Swampville.

Everyday the sun burns off FC. As it gets warmer (higher sun angle/ more daylight) it will burn more per day. Then it gently falls through the fall back to very little for the winter. A big storm or swim day may also consume some FC, although likely not as much as the UV/sun.

Your mission, is to remain free and clear above min FC per your CYA. Loosing 1 ppm per day right now ? Then an 7 is a couple days supply at 50 CYA. In July you might lose 4ppm a day and a 7 is barely gonna cut it.

View attachment 629410

You adjust the cell runtime (%) or the hours of said % to make more or less FC to match the loss of that part of the season. Plus a little wiggle room for a particularly high UV day or big storm out of the blue.

24 hours at 25% = 6 hours producing
12 hours at 50% = 6 hours producing
6 hours at 100% = 6 hours producing.

Math at will, it's all the same.

An Aquarite T3 cell will make 1 FC about every 4 hours for you. Again, math at will with hours or % when you need 3ppm a day. (Etc). In the above examples, 6 hours producing will make about 1.5 ppm per day, probably about right for right now.

Click on the below links to dive further.

Pool Care Basics
FC/CYA Levels
I have a quick question for you. After remaining about the same last week, my numbers this week are a bit different. And with me leaving town for a few days, I wanted to get you opinion on if anything needs addressing. Still a few weeks out from swimming weather but would you work to adjust any of these?
FC 8.5
PH 7.2
Alk 50
CYA 40
Salt 2800 ppm
 

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my numbers this week are a bit different.
Most tests have a variance of +/- 1 drop. For CYA it's +/- 10. Maybe a couple inches of rain lowered you a little (keep in mind that 2 inches in 60 inches average depth is 1/30th) and maybe the tests fluctuated the rest.

This is high evaporation time also so folks will see some drop with refills, but not even realize it if they have an autofill.

If it's still too cold for the SWG, don't worry about the salt until you get back. If the SWG is working, I'd add 400 ppm.

Make sure to boost the FC enough to cover the loss while you're away.
 
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Most tests have a variance of +/- 1 drop. For CYA it's +/- 10. Maybe a couple inches of rain lowered you a little (keep in mind that 2 inches in 60 inches average depth is 1/30th) and maybe the tests fluctuated the rest.

This is high evaporation time also so folks will see some drop with refills, but not even realize it if they have an autofill.

If it's still too cold for the SWG, don't worry about the salt until you get back. If the SWG is working, I'd add 400 ppm.

Make sure to boost the FC enough to cover the loss while you're away.
Thank you!
 
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Reactions: Newdude