Results of first TF-100 test ran on fill water

[BrandonD]

Alright... second battery of tests performed. See first post for results ran on the straight fill water. This is results from today after about a week in service.

FC (using the FAS-DPD test): 6.5
CC: 0.5
pH: 6.8
TA: 160
CH: 420
CYA: 30

Water clarity: pretty much crystal clear. Temp: 74F.

I took these tests about a two hours after I added the day's chemicals, which included a heaping amount of bleach and MA as usual. My target was 5ppm for chlorine and 7.2 for pH. Not sure if my pool size estimation is incorrect or what but if the pool behaves anything like it has every day for the past week, it'll be back up at 7.5-7.8 by this time tomorrow.

TA seems a bit happier at 160... a loss of 40 due to the ~180oz of MA I've added over the last week. It's spot on with the 'if you do x, then y happens' part of the Pool Calculator. Still quite high, and it's still jacking up my pH constantly, hopefully it'll even out in a few weeks if I keep on feeding it MA.

CH... wow... seems to have increased. I did this test for the first time using the Speed Stir so I'm pretty sure it's accurate. The first time I did it today I thought the color turned purple, so I looked at the fading endpoint notes and re-did the test, adding the 5 drops of the titrant first before the other chemicals. I guess it could still be a bit off and I can re-perform it again and even record it if you guys think I should. Is the high CH a concern? The recommended levels says it should be between 0-350.

CYA... I added enough stabilizer last week to get it up to 40. But as you guys know I've been cleaning my filter like a maniac since filling the pool, so maybe part of it got cleaned out... although I did add it in via the sock method. Should I wait a few days and re-test, or go ahead and add enough stabilizer to bring it up?

 

[duraleigh]

Well, you're getting things homed in....you have little bit more to go.

CH is fine where it is. You don't want it too much higher but it's OK.

I would use poolmath and add enough CYA to get 15 ppm more......that should get you close to 50 which is just right for Central Florida.

Stop using MA for now. Your pH is too low (7.4 is better)

Last, read the article in Pool School on the correct way to permanently lower TA (aeration/acid) That'll lower your TA and simultaneously raise your pH where it needs to be.

 

[BrandonD]

Thanks Dave. I'll raise the CYA, but should I continue MA? I know my pH is low, I must've overshot today when I added the MA, but I've been fighting high pH (because I think my TA?). If every day for the last week is any indication, my pH will be 7.5-7.8 tomorrow. I usually add MA every day targeting 7.2 but I guess I didn't calculate correctly today or didn't read the pH right, giving me a lower pH than I wanted.

 

[duraleigh]

If your pH jumps from 6.8 to upper 7's in 24 hours something is badly incorrect. Repeating my above post....

Stop using MA for now. Your pH is too low (7.4 is better)

Last, read the article in Pool School on the correct way to permanently lower TA (aeration/acid) That'll lower your TA and simultaneously raise your pH where it needs to be.

Did you read that article?

 

[BrandonD]

I have read that article... long before the pool was installed. I think it was JasonLion who referred me to it at the start of this topic. Am I correct in thinking I can't do that until my pH is somewhat stable, though? I've been told on here to never let pH rise above 7.5. Literally every day my pH has been between 7.5 and 7.8, and I added enough to bring it down to 7.2 each day. Which apparently might've actually been enough to bring it down to 6.8. I have about 1.5 gallons of 31.45% MA in it after less than ten days of service. I am afraid if I start aerating now I will get home to a pH of >8 since it is rising so much on its own. Is that a valid concern?

I thought my constantly rising pH was due to my high TA and that it would slow down as TA lowered with additions of MA.

I'll post back tonight with my pH results, but I'd bet my lunch it's around 7.5 if pools are habitual creatures.

 

[duraleigh]

I've been told on here to never let pH rise above 7.5

Acceptable range for pH is anything in the 7's. Do you remember where you saw that?

TA lowered with additions of MA.

Lowering TA with muriatic lowers your pH, too. Lowering TA by following the article in Pool School allows you to lower TA and keep pH where it is.

 

[BrandonD]

From JasonLion, earlier in this topic:

Because your TA and CH levels are both high (assuming test results are correct) you are at risk for calcium scaling. With TA at 200 you want to keep the PH at or below 7.5. You want TA below 120 to not worry so much about PH, perhaps lower if constantly rising PH is an issue. With high fill water levels you will need to keep an eye on TA and CH levels to a greater extent than others would. I expect that your CH will go up over time and managing TA and PH will continue to be an issue, but only time will tell for sure.

Yes... I know MA lowers pH and TA... that's how my TA is 160 after a week. Do I really need to aerate if I'm lowering TA at a rate of 40/wk just by managing my daily rising pH? I'm assuming as TA continues to lower my pH will stabilize and won't go up to upper 7's every day and I'll need to aerate to bring TA down further? I know aeration will raise pH and and the MA will lower it and TA back down. But even that article says to aerate until a pH of 7.6, I get that every day as it is without aeration.

 

[BrandonD]

pH today was up to 7.5, and that's after I added a couple inches of water yesterday (fill water has a pH of 6.8.) You mentioned this could be mean something is badly incorrect Dave, but I thought it was just a symptom of high TA? Should I be doing something else?

Lowered the pH down to 7.2 so it doesn't go over 7.5 before next time, and have 15ppm worth of CYA in socks in the pool now.

On the high iron front... cleaned the filter for the first time in three days, it looked pretty good but still had a good amount of murky iron water coming out of it. I probably could've gone a couple days longer before cleaning it. The skimmer sock filters are still doing a good job surprisingly.