At first sign of algae ...

[Mdragger88]

Use a 10ml sample, a heaping scoop of dpd powder & each drop counts as .5
This will save reagents & be plenty accurate. It’s also less drops to keep track of.
Be sure to do the test the same way each time (a speed stir helps with this & lets you focus on the counting)
Hold the bottle completely vertical & let the drops come out. About a drop per second. Don’t squeeze the bottle.
Do the test, call it & move on. Doing it over & over in short succession is only using more reagents & confusing things.
No need to do an Overnight Chlorine Loss Test until you’re crystal clear with no recurring algae (dead or alive).

 

[ChasPro]

Use a 10ml sample, a heaping scoop of dpd powder & each drop counts as .5
This will save reagents & be plenty accurate. It’s also less drops to keep track of.
Be sure to do the test the same way each time (a speed stir helps with this & lets you focus on the counting)
Hold the bottle completely vertical & let the drops come out. About a drop per second. Don’t squeeze the bottle.
Do the test, call it & move on. Doing it over & over in short succession is only using more reagents & confusing things.
No need to do an Overnight Chlorine Loss Test until you’re crystal clear with no recurring algae (dead or alive).

Yes, I am doing all of that as described, except the part about not squeezing the bottle. I'll do that going forward. My measurements were consistent and predictable throughout this whole period until (a) new dpt chems, (b) more rain than earlier in summer. Would either of these result in the wild swings in test results. I don't think my technique is that different each time, which is why I'm considering other affects. Thoughts?

 

[ChasPro]

Advice was to use 1 heaping dose of DPD powder, and then let drips fall naturally from the bottle without squeezing, and swirling tube constantly.

Did all but the natural drips ... nothing was dripping out without a little encouragement.

So, each drip I went through the whole cycle of uprighting the bottle, turning over to full inverted position, and applying slight pressure to encourage the drip to form. Then swirl tube while resetting the bottle.

...
...
...

To be clear, I'm attempting ONLT because all of the other conditions appear to be met. Last night the FC was 21.0. This morning it was either 27.5 (uncirculated overnight, still), 23.5 (circulated for 30 min.), or 26.5 (circulated for 60 min.) depending on which test you prefer ... none of which make sense higher than the night before, with some overnight rain.

Now we sit at 17.5, which makes sense compared to last night's 21.0. Correct or not ... at least it makes sense.

I'll test at dusk and dawn again to see if I get reasonable readings and hopefully I'm done.

 

[Mdragger88]

Are you certain your swcg cell was off?
Also if you got new reagents during these tests that can explain some differences.
At any rate if you’re using all new stuff now you shouldn’t need to worry about that.
You can use very light pressure just don’t squeeze the bottle- as this makes the drops come out too fast & too small. No need to keep flipping the bottle. You just want fat drops at a rate of around 1 per second. This also makes it easier to count- for me anyway.
Pro tip- set up your coffee pot tonight for 35 minutes before sunrise
It makes the morning test much more enjoyable ️
Oh & good luck! Fingers crossed

 

[ChasPro]

My SWG has been out of commission for a month. All liquid Cl from pool store since. (No, haven't pivoted to Walmart bleach yet ... I'm a slow ship to turn ...). Only thing added to the pool besides the documented Cl has been the rain and any accompanying tree debris.

Last evening:
Vacuumed and brushed... very little there.
9:13 PM: 17.5 FC

Today's morning report:
not shining on pool yet ... partially cloudy, just behind neighbors house. Took two different samples and measured each twice ...

Still water: 33 (16.5 FC), 38 (19.0 FC)

Circulate 30 min: 37 (18.5 FC), 37 (18.5 FC)

Average: 18.1

Drop size or amount of DPD powder or both? "One heaping scoop" is less predictable than "two level scoops" as advised by Taylor. I did observe variations in the size of the drops. 5 drops difference, and only recently unpredictable? Smaller readings are probably more reliable based on full drops, where higher readings imply partial drops.

I've been refilling the small bottle for a couple of years. Maybe a new dropper would behave more consistently. I'll do that just in case.

Either way, we have one reasonable (<= prev night) reading at 16.5, which is ONLT of 1.0.

All the other SLAM conditions are met.

I'm done chasing it if there are no objections

 

[Mdragger88]

The only way fc could have went up is if you weren’t circulating for sufficient time before taking one of the samples.
For the oclt & all other tests the water should be circulating for at least 30 minutes.
Going forward just test then & once. Unless you just like buying reagents.
Either way it seems as if you have passed even with your lowest test result.
Henceforth be sure to aim for high target for your cya FC/CYA Levels to prevent broaching minimum & risking algae. Be sure to select liquid chlorine.

If your t cell 5 is due to be replaced & you are comfortable with soldering you can add a jumper to your aquatrol to be able to use a larger cell that would more adequately support your fc needs without running it 100% 24/7.
Here’s the details on that

AquaTrol owner confused by cell compatibility

Hi, long time lurker here. Thanks for all the information over the years, but now I've run into my own problem. I purchased a used AquaTrol system with cell last year. The system worked reasonably well, but it was obvious that the cell was aged, and even more so now. I'm looking to replace the...

www.troublefreepool.com

Otherwise if you replace your cell with another t5 you may need to supplement with liquid chlorine in the peak of summer. Especially for parties & such.
Here’s The max that cell can produce in your pool - *note* the average algae free pool can use 2-5ppm/day closer to 4/5ppm in the peak of summer.

 

[ChasPro]

Well, I'm not running the pump 24/7, so something will be needed to compensate. I bought a new T-5 in 2020. My SWG unit is failing right now (I'm chatting about that on another thread), most likely the thermistor. If the cell is also failing for some reason, I'll be sure to consider the upgrade. It makes sense to have the production capacity. This is an AquaTrol RJ, so the linked thread does a good job of discussing your jumper advice. Thanks.

 

[ChasPro]

Going forward just test then & once. Unless you just like buying reagents.

I wasn't testing multiple times for the results ... I was trying to figure out how to get a consistent and valid measurement by repeating the measurement when they didn't make sense.

I'll be sure to take circulating measurements from now on for at least consistency on that front ... Thanks for the clarification.

 

[Mdragger88]

I wasn't testing multiple times for the results ... I was trying to figure out how to get a consistent and valid measurement by repeating the measurement when they didn't make sense.

I'll be sure to take circulating measurements from now on for at least consistency on that front ... Thanks for the clarification.

I know- but sooo many drops/tests will definitely make your head spin & have you second guessing yourself
If you’re still unsure whether you’re in the clear you can do another oclt at target fc levels to confirm you’re good- at high fc levels it can get iffy being tired & so much counting/swirling.
In fact any time something seems off (higher fc consumption/ a little cloudy) you can & should do an oclt - much easier & cheaper to deal with early than to let it fester.

 

[ChasPro]

Thanks everyone for your input. The pool cleared up by August 15 and then, since it was cooler here in Buffalo, took another 10 days or so to get the FC down from 24 ppm to 12 ppm.

While that was happening I repaired my SWG and got that running again through the calibration, etc. Ran the T-5 Cell at 45% for a few days ... still cool outside ... which kept up and added FC up to 14 ppm.

Shut off the SWG and will use remaining liquid chlorine this season through September 10th, when I will close the pool for the season.

Crystal clear, nicely vacuumed and brushed... several 80 degree days in store ... water at 69 degrees today.

Next year ... maybe a pool heater

 

[Mdragger88]

Save your chlorine for the closing slam.
Your swg should still work with that water temp.

Closing (Winterizing) Your Above Ground Pool

Closing an above ground pool at season’s end should be a fast and worry-free process. Learn the basics of above ground pool winterization in easy steps.

www.google.com

 

[ChasPro]

Save your chlorine for the closing slam.
Your swg should still work with that water temp.

Closing (Winterizing) Your Above Ground Pool

Closing an above ground pool at season’s end should be a fast and worry-free process. Learn the basics of above ground pool winterization in easy steps.

www.google.com

Yeah ... I have 6 gallons... probably enough for me and my neighbor to close our pools this year. Thanks for the link to review.