First test with new kit

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RedDmax

0
Aug 20, 2015
17
Georgia
Been testing water at pool store and at home with basic pH/chlorine test kit, my Taylor 2006 test kit came in today. We built our pool 10 years ago and was chlorine for first 5 and salt generator for last 5 years, been much easier to maintain with the salt. Our pool is Gunite 16x32 with 3.5ft shallow end and 6.5ft deep end, pool builder says about 17K gallons. Our pool is screened in and stays about 5-10 degrees cooler than neighbors that aren't shaded, I've put a solar blanket over it this summer to warm it up a little.

I recently had what appear to me to be black algae spots along one side, this is same side that had some light green dust like material in the corners. My wife says the trouble is from the increased shade from the solar blanket. I decided to take better control of the chemicals in the pool and order a quality kit. I tested the water with the kit and also took some water to pool store for comparison, they have a nice computer system that they put the water in a centrifuge type device.

My Taylor test results Store results
pH 7.4-7.5 7.6
FC 1.8ppm 1.3ppm
CC 2.0ppm 1.67ppm
Alk 30ppm 35ppm
Cal 290ppm 236ppm
CYA <30 6
Copper .1
Iron .1
Salt 3000

Store said everything was OK but needed stabilizer, I bought a jug and told me to add half today and half tomorrow. Said chlorine and everything else was OK, I thought should try to get chorine up a little.

We have no ladder or anything in the pool, the only metal is the ring around light and it looks terrible, dark rusty color and not smooth. I have had several small rust appearing lines in the bottom of pool over the last several years. They look like rust lines from the metal ties that rebar is secured with under the Gunite. I've wondered if its where the unite might be thin and rusting through. Pool installer looked at them and say looks like where something was dropped in pool like and nail and rusted. I disagree because nothing has ever been in our pool like that.

I recently discovered this forum and was wanting some opinions on how my pool is doing. Is there anything else I should check/change?
Thanks
 
RedDmax said:
Been testing water at pool store and at home with basic pH/chlorine test kit, my Taylor 2006 test kit came in today. We built our pool 10 years ago and was chlorine for first 5 and salt generator for last 5 years, been much easier to maintain with the salt. Our pool is Gunite 16x32 with 3.5ft shallow end and 6.5ft deep end, pool builder says about 17K gallons. Our pool is screened in and stays about 5-10 degrees cooler than neighbors that aren't shaded, I've put a solar blanket over it this summer to warm it up a little.

I recently had what appear to me to be black algae spots along one side, this is same side that had some light green dust like material in the corners. My wife says the trouble is from the increased shade from the solar blanket. I decided to take better control of the chemicals in the pool and order a quality kit. I tested the water with the kit and also took some water to pool store for comparison, they have a nice computer system that they put the water in a centrifuge type device.

My Taylor test results Store results
pH 7.4-7.5 7.6
FC 1.8ppm 1.3ppm
CC 2.0ppm 1.67ppm
Alk 30ppm 35ppm
Cal 290ppm 236ppm
CYA <30 6
Copper .1
Iron .1
Salt 3000

Store said everything was OK but needed stabilizer, I bought a jug and told me to add half today and half tomorrow. Said chlorine and everything else was OK, I thought should try to get chorine up a little.

We have no ladder or anything in the pool, the only metal is the ring around light and it looks terrible, dark rusty color and not smooth. I have had several small rust appearing lines in the bottom of pool over the last several years. They look like rust lines from the metal ties that rebar is secured with under the Gunite. I've wondered if its where the unite might be thin and rusting through. Pool installer looked at them and say looks like where something was dropped in pool like and nail and rusted. I disagree because nothing has ever been in our pool like that.

I recently discovered this forum and was wanting some opinions on how my pool is doing. Is there anything else I should check/change?
Thanks
Click to expand...

Welcome to TFP! :wave:

Trust your Taylor results over pool store testing, especially the computer based testing.
Is the CC number actually CC (combined chlorine) or the TC (total chlorine = FC + CC)? If that is CC, any time you have CC at 1 ppm or above, you need to SLAM the pool. See the link in my signature.

Here at TFP we recommend higher levels of CYA for SWG chlorinated pools as it allows your FC to be shielded properly from sunlight (UV light) and allows your SWG to be able to maintain adequate chlorine levels with less run time, less % output on the SWG. Please see the the CYA/Chlorine chart in my signature for our recommendations there. In Georgia, I'd certainly recommend a CYA of 70 ppm to start and monitor your FC levels versus SWG output.

Your alkalinity (TA) is low, which might lead to problems with pH bouncing around erratically when you need to adjust pH. I'd suggest bumping that TA up to 60 ppm and see how your pH responds. SWG systems are a source of aeration so lowish (60-80 ppm) TA levels are recommended. See the recommended levels for all other levels other than CYA/FC in this chart. Pool School - Recommended Levels

The rust may we be rebar coming out through the gunite from rebar if it's close to the surface. If you input all your numbers into Pool Math (see link at the top of the page) you can see that your resulting CSI number is about -0.82 depending on actual temperature. Anything less than -0.6 for CSI is an indication of a corrosive environment for plaster pools. This could lead to erosion of your plaster surface and contribute to the appearance of shallow rebar. It may also be a problem for your metal light ring, but I'm not entirely well versed in CSI and how it affects metal corrosion. Low pH can certainly cause metal corrosion.

If you were to up your TA to 60, CH to 350, CYA to 70 and maintain a pH near 7.8, you can see that your CSI number would be at about -0.11. This is certainly a safer CSI range to operate your pool and will not risk plaster corrosion.

- - - Updated - - -

Also, update your forum signature with details about your pool. It helps immensely for experts and other users to quickly see what kind of pool you're dealing with and give better advice.
 
I typed the chlorine in wrong, my CC was .2ppm, the TC was 2.0ppm using my test kit. From store the FC was 1.36 and Total was 1.67. My CYA was 6 from the store, it didn't show up on the post the way it did when I wrote it, had them separated by many spaces. My water temperature is 86 right now, I went and looked when doing the pool math calculations you suggested. I will add the required baking soda (120oz weight) to get the TA up. I guess that I go to the pool store to get product to raise the CH? Is the goal to get the CSI to 0.0? Thanks for all the help/info. I've learned more today about pool chemistry than in 10 years of ownership. I will get the my pool info and add to my signature tomorrow.
 
Thanks, I will add the baking soda, some bleach and turn up my SWG tonight. I will recheck the numbers tomorrow afternoon and post results. I haven't had to add water in awhile, we are near Florida and been getting a fair amount of rain. When I do add water to pool it is from a well.
 
Sorry didn't post results up the next day, spent the whole weekend with a fever in the bed. Can't remember the last time that I've been sick in the bed for a single day especially three days. Checked the pool this evening and the numbers are as follows:

FC 5.4
CC .2
pH 7.7
TA 60
CH 300
CYA <30 still

I added the other half of the 6 lb jug of dry stabilizer this evening. How long before the CYA will start to show up? I was told always told to never have the pH up (in the pink/red) and have high chlorine, that it would damage my finish. Is that correct? I was planning on adding acid to keep near 7.5 but was told on here to keep near 7.8. According to my inputs I have a CSI of -.13 right now ,should I leave things alone. I did get a metal brush this evening and brushed the spots that look like may be black algae spots.
 
I will get in the water and do the fingernail test tomorrow evening, I'm pretty convinced it is black algae. I may need to read up on the SLAM I've heard about but never done. I guess this is a good time since my CYA is pretty much nonexistent as this point.
 

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Going to SLAM it starting tonight. Even if the spots aren't black algae I still get a pale green dusting in the corners/shaded spots. Just checked pH 7.4 and FC 9.5, CC .5 How hight do I want to get my FC with the SLAM? The chart for SWG starts at CYA of 60 and a Shock FC of 24. I'm showing CYA of less than 30 with the test so don't really know a number. I was going to get the FC up to 15-18? That's just me guessing where I should try and reach. I've had my SWG turned up to 80% for 2 days, going to put it on boost and add bleach.
 
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