Re: Spring opening cloudy pool excessively high PH > 8.2
Hi aylad,
Thank you, and yes, I figured it out just before I ran out of titrant. I initially thought that the 10 ml sample was a second resort, but not the preferred method. Is there ever a time when 10 ml is an unreliable sample size? My last sample was 25ml because I forgot and then it was too late.
As for my OTO readings...they are uncertain. Since opening the pool this year, whether I use OTO or FAS-DPD, my samples are always slowly changing color and never "permanent." For instance, here is the results of my morning testing:
Water temp = 64 degrees
HTH OTO Kit - (5 ppm is the highest reading)
Added 5 drops to sample - Counted to 30 ("1/1000, 2/1000, etc." method)
TC=1.0 color
@ count of 60 TC=1.0 color .....but.....
@ count of 90 TC=2.0 color
after 2-3 minutes TC=5.0 color
After 5 minutes, TC was higher than 5.0 and a deep gold color
PENTAIR 4-way OTO kit - (3 ppm is the highest)
Added 5 drops to sample - Counted to 20 using 1/1000 method
@ count of 20 TC=1.0 color
@ count of 40 TC=1.5 color
@ count of 60 TC=2.0 color
@ 2 minutes TC=3.0 color
@ 3-4 mins TC=darker than 3.0 color and deep golden
I'm pretty good with discerning color. I don't know at what point the color should be "recorded" and considered correct. I read somewhere when samples sit too long they can have a reaction to the oxygen in the air and so they will get darker naturally because of that, so logic says "within a few seconds after swirling" should be correct. Yet the OTO kit says FC can be measured by watching for results a few seconds after dropping and swirling reagent, but if you wait a few minutes, the color will give the TC reading. ??? Then I read in a post on this forum waterbear commented that this information was wrong and OTO tests TC only. Period. I've read enough on this forum already to trust more in waterbear's opinion (as well as all the moderators.) But there was still is no indication anywhere as to when that TC is properly reflected in the color, especially if it's gradually changing at a slow but consistent pace for an entire 5 minutes.
My FAS-DPD never achieves permanent "clear" regardless of the amount of titrant drops added which is why I ran out so fast. After a reasonable amount of drops that I was expecting, a sudden change from the pink to a very light pale/blush pink occurs and I think, "cool, we're almost there..." After that, additional drops turn it clear immediately and then almost as fast the water begins to turn back to the blush pink. I kept going until it was permanent as some of the other posts had instructed. However, each subsequent drop, the clear would hold a few seconds longer than the previous and then start to change to blush pink again. This went on forever. The "permanence" was the blush color - not an absence of color. I never knew at what point the "change" to clear could reliably be considered permanent. So every time, when I was about to add the reagent for the CC part of the test, my sample was already turning blush pink before the first drop or gradually darkening from a blush pink. Then the first titrant drop would turn the sample to a raging hot pink, way darker than the DPD powder did in the FC part of the test. By the fifth drop, it was obviously going to take almost a quarter bottle of the titrant before any change in the color would start to happen. The times I forged ahead, I would get the faint/lighter pink finally, but again - never could get to a "clear" absense of color permanently. It was frustrating not knowing if the 10, 15, or 30 seconds it held the clear (or was absent of color) was reliable because as I was writing down the results, I'd glance over and there would be a definite pink returning.
Learning to correctly use the K2006 can wait. Maybe I should just create a new thread for needing help with these kits and move the previous paragraph to that. I'd rather wait for one of the moderators to let me know if I should do that before cluttering up another thread with my wordiness.
For right now, with following instructions from Ben up to this point, I believe my greatest and most pertinent need is to know exactly when to capture that OTO reading so that I can get my CC under control and get my kids swimming. That is, if there is any CC to control. Which I'm still convinced there is, but I'm just a beginner. I have no idea if I'm losing chlorine over night or not and if so, if it is significant. I also don't know if I have a higher CC than an FC still.
I need help with proper OTO reading under these circumstances. Do I add chlorine only when the color is below the 3.0 ppm color and not look for orange-ish anymore? How will I know when it is safe for my kids to swim? We've got 80 degrees expected in a few days and their whines are escalating just as fast.
Why wouldn't I ever see orange or brown with the high amounts of chlorine I've added? Is it possible that 50 ppm could be eaten up in under an hour even if my CYA is so high, my pH is 7.2 and my Alkalinity is 140 AND it's in the evening with no sun? If it is possible, what would cause that? Keep in mind ...... I do not have ANY odors, or any discoloration. The water is beautiful and sparkly.
I'll post our readings from this evening as best I can. We weren't planning on adding bleach first again tonight unless it was necessary.
32x16 IG 18K vinyl Grecian; all Hayward equipment: S244T sand filter; .75HP Super Pump; Booster Pump 5060 & Viper; H250IDL2 Heater; CL200 feeder; PF:6.5
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