Guidance needed, 3 years using TFP and I am at a loss (Solved)

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Something still seems off. Tonight's FC at 7 pm was 7.5. Starting with last night's 9 ppm - 1 for overnight +2 from the swcg should have left me around 10 ppm. So I'm showing 2.5 more ppm loss than expected. Which means I should be at 45% on the swcg just to maintain 7.5?

Math is hard. 9 -7.5 is 1.5. So I lost 1.5 ppm today. To make up for that, I need to set the swcg at 20% (current) + 15% to break even tomorrow and stay around 7.5.

Even redoing that math, that seems out of character. Historically, I haven't been over 25% until the deep summer months and even then I think I only ever set it as high as 35%.

Going to test again. It has been cool temps overnight, and earlier tests in the week didn't show this much of a difference when they were further away from CYA minimums than these recent tests. I would have thought as I get closer to protected CYA levels, the less FC I would lose versus earlier post slam losses.
 
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New sample

10 ml 15 drops, 7.5 FC
25 ml 32 drops, 6.4 FC

I know comparing apples to apples, so going to go with comparing the 9 FC from yesterday to today's 7.5 FC. Still, that leaves me quite a bit in the hole. I guess I'll wait an hour and do another after dark for OCLT.
 
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4/25 10:30 pm 25 ml sample
FC 6.8

4/26 6:10 am 25 ml sample
FC 6.6

So, OCLT passed. Going to run the swcg at 35% and see where we land this evening. At least I don't have to get back up at 5:30 in the am lol. I guess I am just misjudging daytime consumption and/or my swcg has lost like 20 or 30% efficiency.
 
jsnpckns said:
4/25 10:30 pm 25 ml sample
FC 6.8

4/26 6:10 am 25 ml sample
FC 6.6

So, OCLT passed. Going to run the swcg at 35% and see where we land this evening. At least I don't have to get back up at 5:30 in the am lol. I guess I am just misjudging daytime consumption and/or my swcg has lost like 20 or 30% efficiency.
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No need to waste your reagents with the 25ml sample.
 
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jsnpckns said:
Math is hard. 9 -7.5 is 1.5. So I lost 1.5 ppm today. To make up for that, I need to set the swcg at 20% (current) + 15% to break even tomorrow and stay around 7.5.
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One idea is to set the SWCG at your desired replacement FC ppm, then add liquid chlorine to reach the level of FC you want to hold. So if 9 is your target, and you are replacing 2ppm per day - set the SWCG for 2ppm (% vs pump runtime) and use LC to raise FC from 7 to 9ppm. This way you are not jockeying the SWCG % back and forth.
 
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You can do an overnight chlorine gain test now that you’ve eliminated algae as a suspect.
This does involve getting up with the roosters again though 🥴
Basically leave the pump & swcg running all night & see what you get. (The difference) then compare to poolmath estimates are for your % & run time.
This takes the sun out of the equation.
Note that poolmath estimates are just that - estimates. But it will give you a better idea of what your cell is doing.
 
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Besides wasting supplies, having 2.5X the drops is also 2.5X the human error making said drops.

I know it seems so simple but none of us are a machine. So. :)
 
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Well, I wanted accuracy last night and this morning. When I tested 7.5 FC with a 10 ml sample twice and then tested with a 25 ml sample twice, I got 6.4. Now I'm sure about the oclt, I can go back to the 10 ml sample. I don't mind wasting a few extra drops here and there if it gives me peace of mind tbh.

I am going to test this evening after the pump shuts off and see what my evening FC is after running 12 hours at 35%. One of the nice things about the 12 hour run time with the IC40 is every 10% swcg on time is ideally 1 ppm FC. I know that's not real life accuracy.

If I'm not between 6 and 7 FC this evening , I'll run the ocgt.
 
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Ok, so I re-tested CYA. I am... upset. I tested this before restarting the SLAM with good liquid chlorine, and it was 70. Now, I have taken 3 sample from different parts of the pool and they are all between 30 and 40. Pump still running, all samples collected elbow length below water line from deep, mid and shallow end.

I used a brand new bottle of melamine, 5/25 use by date from the taylor kit. The sample bottle is the original from the kit. Could it have build up throwing off the test?

I am perplexed. I pumped a sizable amount of water after the rain storm on 4/10 and cleaned the filters on 4/14. I restarted the SLAM on the 15th with what I read as between 60 and 70 and recorded 70. I did the whole SLAM off of 70. I added maybe 500 gallons of water over the past week as its been windy and warm during the day and the water level has gotten low enough that my first step is not underwater.

I have less than a gallon of liquid CYA. I guess I'm going to measure that out and get more tomorrow to make up the rest to get back to 70 or 80. I don't think I have a leak... even if I accepted I recorded too high and the CYA on the 15th was closer to 60, that's a 33% loss. I've only made up about 6% of the pool in fill water over that time. Please don't let me have a leak...

FFS. I don't even swim in this pool.
 
jsnpckns said:
Ok, so I re-tested CYA. I am... upset. I tested this before restarting the SLAM with good liquid chlorine, and it was 70. Now, I have taken 3 sample from different parts of the pool and they are all between 30 and 40. Pump still running, all samples collected elbow length below water line from deep, mid and shallow end.

I used a brand new bottle of melamine, 5/25 use by date from the taylor kit. The sample bottle is the original from the kit. Could it have build up throwing off the test?

I am perplexed. I pumped a sizable amount of water after the rain storm on 4/10 and cleaned the filters on 4/14. I restarted the SLAM on the 15th with what I read as between 60 and 70 and recorded 70. I did the whole SLAM off of 70. I added maybe 500 gallons of water over the past week as its been windy and warm during the day and the water level has gotten low enough that my first step is not underwater.

I have less than a gallon of liquid CYA. I guess I'm going to measure that out and get more tomorrow to make up the rest to get back to 70 or 80. I don't think I have a leak... even if I accepted I recorded too high and the CYA on the 15th was closer to 60, that's a 33% loss. I've only made up about 6% of the pool in fill water over that time. Please don't let me have a leak...

FFS. I don't even swim in this pool.
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Replacing water will do that and the test has 10-20ppm error tolerance so I wouldnt get too worried. Theres no requirement to have the CYA at 70. Its just that some have found that it protects the chlorine a little better in the summer heat. Why not wait a bit or just use whats left in the bottle to bring it up to a solid 40 or 50 and leave it there. If you feel a real need to increase it later, then do it at that time. No big deal either way.
 
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Bperry said:
Replacing water will do that and the test has 10-20ppm error tolerance so I wouldnt get too worried. Theres no requirement to have the CYA at 70. Its just that some have found that it protects the chlorine a little better in the summer heat. Why not wait a bit or just use whats left in the bottle to bring it up to a solid 40 or 50 and leave it there. If you feel a real need to increase it later, then do it at that time. No big deal either way.
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Ok. I Added the remaining 64 oz, and I will give it a few days and retest. Not a fan of the test. I know CYA is a slow roll. I am letting my anxiety run away with me.

The lower CYA would explain the higher than expected daytime use though right? Assuming my swcg is running OK, and I passed the oclt. I have been comparing it to last year when I was at 70 CYA and puzzling over this new demand level, which spawned this whole thread to begin with.

I don't know if this is a case study of how well TFP works or a case study for needing my head examined because I over-analyze.
 
Tested FC at 6:55 pm, 10 ml sample FC 7.5, compared to 10 ml sample at 7 pm on 4/25 at 7.5. I think I found my % spot on the swcg at least. That makes me feel a little bit better that I have arrested this descent using only the SWCG. Even if its losing efficiency, I'll just run it higher till it quits I guess.

Going to run the swcg overnight at 35% for 12 hours and see how close to the 3.5 gain I get.
 
jsnpckns said:
Tested FC at 6:55 pm, 10 ml sample FC 7.5, compared to 10 ml sample at 7 pm on 4/25 at 7.5. I think I found my % spot on the swcg at least. That makes me feel a little bit better that I have arrested this descent using only the SWCG. Even if its losing efficiency, I'll just run it higher till it quits I guess.

Going to run the swcg overnight at 35% for 12 hours and see how close to the 3.5 gain I get.
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Great.
Since you have added CYA, note that the "loss of FC" may change slightly because the purpose of CYA is to protect the FC against UV loss.
I guess I saying this because don't try to over analyze the daily FC loss. That is why I keep some LC on hand. If there is more than expected FC loss or the pool had a lot of activity, I simply add some LC and don't adjust the % output of SWCG. It all works well over time.
 
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10 ml sample at 7 am, 21 drops. FC 10.5.

So the swcg is making chlorine and pretty close to the expected 3.5.

Thank you guys and gals for your help. I'm going to take my lizard brain into the back room now and have a talk lol.
 
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Tested my city water and set up a side pool to track it whenever I test it as suggest. Clear but yellow tinge.

FC 1 (two scoops barely turned pink on a 5 ml sample)
CC 1
TA 200 (this is surprisingly higher than last year, which was around 120)
CH 10
pH 8.4 (violet pH, added 3 drops of acid demand to read 7.8, so just estimating 8.4 since each drop typically gave me .2 on the comparator in the past.)

grabbed the 5 gal bucket and did a time test. 30 s to fill to the handle so about 10 gpm. So I was pretty close about that.
 
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Another update, just for gits and shiggles:

Seem to be holding pretty well at 10-10.5 FC with 30%/12 hours on the SWCG. pH is showing stable at first blush at 7.8 without going darker, so actual FC is probably between 9 and 10. Got some free water from Mama Nature on Monday so that's always nice. Just enough to top me up, not enough to pump off.

I had added the 64 oz of stabilizer I had left on the 26th, retested on the 30th and arrived at 60 CYA. Going to wait for the 50 CYA standard from tftestkits to train/retrain myself before I add more, then will probably do it in 5 parts increments to get back between 70 and 80. I think once I do that, I'll see a better retention of FC over the day and probably be able to reduce my swcg maintenance % back to around 20-25%.

Which is where I expected to be when this whole things started. It is obvious that there is some efficiency loss showing on the swcg but nothing I can't live with.

My summer mantra will be "Don't be lazy, but test and be patient".
 
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