Help understand results from first test

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M

Merovingian

Member
Jan 18, 2021
8
Los Angeles, CA
Hi Everyone,

First time pool owner. I've read through the pool care basics, and ran my first test using the TF-100 test kit. I'm not sure I really understand the results though because some of them are well above the recommended range, so I'm not sure if I did the tests wrong
PH = 7.8
FC = 12.5 (recommended range on the Pool Math app is between 1 and 3)
CC = 0
CH = 1,300 (recommended range on the Pool Math app is between 0 and 650)
TA = 120 (recommended range on the Pool Math app is between 50 and 90)
Salt = 3,000
CYA = Tested twice, it was inconclusive both times. I followed the instructions that came with the TF-100 test kit but I could still see the black dot even after filling the test beaker all the way
Temperature = 60F

The pool is a 20K Gal Salt Water pool with a spa. Dimension is 36 x 18 (with depths from 1ft to 6 ft). I'm not sure if it's vinyl or concrete, is there an easy way to tell? I can post pictures, if that helps
 
Welcome to the forum!
Great job on getting a quality test kit! I suspect the pool is plaster as vinyl pools in S California are nearly non-existent.
Your results look pretty normal for a not well maintained pool. I suspect this pool was managed by a pool service.
The CH is quite high. Do you have scale buildup on the water line? You essentially have no choice but to drain and refill the pool, or hire a Reverse Osmosis service, to remove the calcium from your water.
No CYA is odd but as you have a SWCG, many pool services have little clue how to properly manage the pool water chemistry with a SWCG. It no doubt is set too high of generation for the winter.
Make a decision on the removal of calcium before adding any Cyanuric Acid.
I suggest you read ABC's of Pool Water Chemistry.
 
hopefully someone local that knows your water will chime in soon
how have you been adding chlorine to your pool
looks like calcium/hypochlorite powder
also appears you have zero cya stabilizer in your pool
how long have you "owned" your pool and do you know what chemicals have been added
 
mknauss said:
Welcome to the forum!
Great job on getting a quality test kit! I suspect the pool is plaster as vinyl pools in S California are nearly non-existent.
Your results look pretty normal for a not well maintained pool. I suspect this pool was managed by a pool service.
The CH is quite high. Do you have scale buildup on the water line? You essentially have no choice but to drain and refill the pool, or hire a Reverse Osmosis service, to remove the calcium from your water.
No CYA is odd but as you have a SWCG, many pool services have little clue how to properly manage the pool water chemistry with a SWCG. It no doubt is set too high of generation for the winter.
Make a decision on the removal of calcium before adding any Cyanuric Acid.
I suggest you read ABC's of Pool Water Chemistry.
Click to expand...

Thank you so much, for you help. After looking at some more pictures of plaster pools online, I definitely agree that it's a concrete pool with plaster.
The pool was and is still maintained by a weekly service. They come out and clean the pool, and are supposed to add chemicals but I've never really seen them do it.
I didn't see any scale build up on the water line or anywhere around the pool, so maybe I did the test wrong
I plan to run the tests again this week, just to make sure I didn't do them wrong the first time, but if they're accurate it sounds like I will need to drain and the refill the pool

How do people typically refill their pool? Tap water? or get some sort of water tanker service? I imagine filling a pool with a hose would take days
 
aussieta said:
hopefully someone local that knows your water will chime in soon
how have you been adding chlorine to your pool
looks like calcium/hypochlorite powder
also appears you have zero cya stabilizer in your pool
how long have you "owned" your pool and do you know what chemicals have been added
Click to expand...

Thank you for your help. We recently moved in and I know nothing about pools, so I kept the previous owners pool service to maintain it. I don't believe they add any chlorine since it's a salt water pool. The CC test also showed nothing which I think no added Chlorine is present.
The pool is about 3-4 years old. I'm not sure what chemicals have been added but I'll find out from the pool service, and report back
 
Merovingian said:
Thank you for your help. We recently moved in and I know nothing about pools, so I kept the previous owners pool service to maintain it. I don't believe they add any chlorine since it's a salt water pool. The CC test also showed nothing which I think no added Chlorine is present.
The pool is about 3-4 years old. I'm not sure what chemicals have been added but I'll find out from the pool service, and report back
Click to expand...
Well, the pool service just responded. They said the pool has never been emptied and refilled, as far as they know, which explains why the CH is so high.
They also said that the Chlorinator (which I think means the salt water cell) stopped working so they've been adding Chlorine and Acid. During the last pool service, they added a gallon of Chlorine
It appears I have to drain and refill the pool.

Any tips on how I should prepare to drain and refill?
 
For the calcium hardness test, just confirm that you're using a 10 ml sample as opposed to a 25 ml sample. Hold the reagent bottle completely vertical, and allow the drops to fall off the tip. Make sure you swirl well between drops.
 
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And I highly recommend repairing/replacing the SWCG and dropping the pool service. They are doing you no favors.
 

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Thanks, for your help everyone. I was finally able to get the pool drained and refilled. In the process, I learnt about quite a bit more about it, including that it is probably 16k gallons (not 20k) since that's what my water meter usage showed. The new water has been treated and I tested it a couple of times, this is what the results show:
  • FC = 2.5
  • CC = 0
  • PH = 7.4
  • CH = 125 (was 1,300 previously)
  • TA = 110
  • Salt = 0
  • CYA = 20
  • Outside Temperature = 74F
  • Water Temperature = 66F
I know I need to get the CYA and CH up. Should I just add enough Calcium Chloride to get the CH up to the lowest end of the recommended range (250), since it will eventually get higher? Or should I just leave it at 125?
I also cannot figure out how to get the TA lower. From what I read, it says I need to agitate the water, but the only way I can think of doing that is by running the filter and moving the water? I’ve run the filter for 16 hrs in total since we refilled on Monday, but TA has not changed
 
Hey Mero !! As your PH is already on the lower side of the scale you’ll need to aerate to bring it up. Once it’s on the higher side, lower it to 7.2 with MA and aerate to bring the PH up again. Each cycle should bring the TA down by 10. It’s a process and takes time so no emergencies. It’s also only slightly on the higher side of the accepted range so it might not need many attempts.

With plaster you will want the CH at 250+ or the pool water will leech it out of the plaster. @mknauss and the rest of the pros above know way more about it than me as I had vinyl so hang tight for their thoughts.
 
Good job on getting an accurate pool volume during the drain and refill. You should raise CH to 250 and, from there, use Pool Math to monitor CSI. Try to maintain CSI in the slightly negative range, between -.30 and 0.0 to avoid scaling. CSI can be most easily adjusted by moving the pH number up or down. TA also has a significant effect on CSI. Don't sweat the higher TA number for now; it helps to offset the lower CH.

Increase CH in stages. As you know, CH will increase with evaporation and top-offs, so you don't want to overshoot your target.

Aeration in your pool can be easily accomplished by pulling water from the pool and returning it to spa, allowing water to spillover into the pool.
 
Thanks, Newdude, and Mike! I think I'm starting to see how all the chemistry affects each other. If I understood you both right, the order in which I should balance the pool is
  1. Raise CH in stages (by adding calcium carbonate until I hit 250)
  2. Keep CSI between -0.30 and 0.0
  3. Once the CH is at 250, raise Ph through aeration and add MA to lower Ph down to 7.2 (this should also bring TA down by 10)
  4. Repeat step 3 until TA is in the recommended range (50- 90)
Does that look right? and to raise Ph, instead of aeration can I us Boric Acid?
 
Merovingian said:
Does that look right
Click to expand...
1-4 are great !! Although with #3 the PH may be up already by the time the CH is at 250 so you may be going straight to MA. See how it goes
Merovingian said:
and to raise Ph, instead of aeration can I us Boric Acid
Click to expand...
I believe that raises the TA a bit so its counter productive.
 
If it was my pool, I would target CH 200. Bring your CYA up to the middle/recommended level depending on how you plan to chlorinate your pool, liquid chlorine or SWG. Your pH and TA work with each other. High TA levels pull up pH, which requires you to add acid. MA additions bring down pH and TA levels. Your pH and TA will find a sweet spot where pH will be more stable as TA drops. In my area, and probably yours, fill water is high in TA which will continue to drive up pH. Continue to monitor and adjust pH as needed. You won't need to add anything to raise pH.

I ran your numbers through Pool Math (I Iike the web version). Even with a CH of 200, you'll be able to achieve a good CSI number by managing pH. Water temps will begin to increase which will bring your CSI up a bit as well.
 
Last edited:
Just made my first visit to a pool store to load up on supplies :) Added 4lbs of Calcium Chloride to raise the CH. Will test the water again tomorrow and add add more in batches to bring the CH up to 200. Then I will raise the CYA, followed by lowering the TA

Fingers crossed all my numbers will be in the recommended range in a few days! Thanks, for your help, again, Newdude and Rancho
 
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dont worry about your ta level for now. it is not too high
as you keep your ph in range .ta will also be kept in range
if you recorded a cya level of 20 on fresh fill, will be margin of error on test as fresh water does not contain cya
test your fill water ph, ta and ch as you will then know what effect topping up your pool will have
 
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