Need guidance.

[DeadAquaRite]

My SWG board died and I discovered it this spring when the pool turned green. A few of the side affects were too much salt added (meter said 1200ppm) and zero FC. Since swim season was a bit away (~June 1), I've been working on it slowly and letting rain/purge help re-balance the salt and TDS rather than doing a big water change. But the wife just informed me our daughter's pee wee softball team is coming over Friday for a (chilly) swim party. PANIC! With 5 weeks now shortened to 4 days, I need some advice.

Where it started:
FC - 0.0
CC - 0.0
pH - 7.8
CYA - 30
TA - 0
CH - 160
Borates - n/a
Salt - 1200 by SWG, guestimated at ~2000
TDS - 5500

Where I am today:
FC - 12-15 (raised with di/trichlor)
CC - 0.0
pH - 7.5 (added 30oz muratic)
CYA - 50 (raised with di/trichlor)
TA - 85 (+12# bicarb)
CH - 160
Borates - n/a
Salt - 3500 per new SWG main board. [s:1262ysrm]>=4000[/s:1262ysrm] (water added, [s:1262ysrm]not re-tested[/s:1262ysrm])
TDS - unk (not re-tested)

Questions
- Is an FC of 12-15 @CYA=50 safe to swim in? in 3 more days?
- Should I let the salt stay at 4K and fall over time by splash and rain/drain
- Is my TDS a safety concern? a general concern?

 

[jblizzle]

First, what does the water look like? If it is green and/or cloudy then swimming in it may not be a good idea.

Second, are you doing your own tests? If not, you should get your own test kit, but that will not happen before the weekend.

When did you add all the di/trichlor? How much did you add and how much should that have raised your CYA? May take up to a week for it to register on the test. STOP using it at this point and only use liquid chlorine/bleach as your CYA appears fine now, unless it is still rising due to the di/trichlor.

We do not even look at TDS typically as it is just kind of a sum of everything in the water ... don't worry about it.

If your CYA is 50 (and assuming you are using bleach for now as your SWG is out), your normal FC level is 4-6ppm. Shock value is 20 and generally it is safe to swim up to shock value.

Also remember, the pH test is generally not valid for FC > 10 (it will read high).

I would recommend, leaving your pump on 24/7 and adding liquid chlorine and holding your FC around 20ppm for the next couple of days (kind of a pseudo-shock process) and hopefully kill anything in the pool. Then let the level come down on Thursday so that it is under the shock value by Friday and should be safe to swim in ... kind of hard to rush these things.

 

[DeadAquaRite]

The water is sparkling clear and CC=0. I shocked it with liquid SH when it first turned. Unfortunately, as the FC=0 showed me I'm still learning about puck dosing rates (a first for me).

Yes, doing my own testing with a Pentair/DPD test kit. I also double check with the test strips (they were a gift) and/or the pool store if I'm going there.

I've been adding tri since I shocked it with liquid SH 4 weeks ago, and I added 4#/2# of tri/di this time last week. By my figures the total additions should have contributed ~26.5ppm of CYA, with 16 of that in the 3 week prior to last week, and 15.5 more added ~7 days ago. I'm measuring a rise of 20. There may be a little more rise in CYA, but the bulk should be in solution by now.

SWG is out, but hopefully that will change today when UPS arrives. I've been using tri/di until today because CYA was also low. I had planned to switched to liquid SH when the CYA hit 60, aiming for a target of 70. ~60ppm CYA is also when I expected to run out of trichlor pucks.

Did not know about the pH error at high FC. Does adding chlorine neutralizer drops not counteract this?

Pump on 24x7 = check. bump chlorine to 20ppm = will do. If I stop on Wed PM and allow for settling on Thurs, why should I anticipate the FC to measure on Fri?


Also, how are you guys measuring high FC levels? I've been taking the specified sample size (6ml) and diluting to 12, 18, 24ml then extrapolating from the observed reading. This is fine if you know what your reading is, but if not you have to "walk" up or down to a measurable reading. Is there a more accurate and less time consuming way? Take this situation. Because of the non-linear gauge on my test vial (and visual error), I only reliably know that my FC is somewhere in the 12-18 range.

 

[jblizzle]

Sounds like you have a decent understanding of the recommended CYA levels and were planning on the rise from the di/trichlor Just wanted to make sure you were aware.

You need the FAS-DPD test for high FC levels. Generally it is difficult to find locally. Leslies has a kit, but not always in stores. Taylor K-2006 includes it or they have is sold separately. The recommended kit is the TF-100 ... see link in my signature. I think the dilution method you are using can add uncertainty.

I am not sure if your can neutralize the FC and then have a good pH measurement.

A "clean" pool will use 2-3 ppm of FC per day, but if you still have any algae hiding (have you done an overnight chlorine loss test?), it could drop more. Like I said for CYA of 50, your should be safe swimming up to FC of 20. But it sounds like your CYA could be higher ... at CYA of 60 shock is 24ppm.

I would still say bump up to about 20ppm today and tonight ... do the overnight test tonight to be sure nothing is living ... if you pass maybe don't bump it up tomorrow and let it fall before Friday. If you still get a significant FC drop overnight, bump back up to 20ppm for tomorrow also.

As long as you have clear water, less than 0.5 CC, pH in range, and FC < shock value, the water should feel fine.

 

[DeadAquaRite]

Sounds like you have a decent understanding of the recommended CYA levels and were planning on the rise from the di/trichlor Just wanted to make sure you were aware.

I've been reading at good website I found. You should check it Out. Www.troublefreepool.com.

You need the FAS-DPD test for high FC levels. Generally it is difficult to find locally. Leslies has a kit, but not always in stores. Taylor K-2006 includes it or they have is sold separately. The recommended kit is the TF-100 ... see link in my signature. I think the dilution method you are using can add uncertainty.

Thanks, I will check it out! Done carefully, dilution doesn't add uncertainty but it does multiply the uncertainty in your existing scale. For example: mine reads .6, 1, 2, 3, i diluted 6:1, and tested in the low 3 - high 2. The most accurate I can be is 12-18

I am not sure if your can neutralize the FC and then have a good pH measurement.

Me either, but my test includes a neutralizer for pH and advises 1 drop for <3ppmFC, 2 drops over 3ppm

A "clean" pool will use 2-3 ppm of FC per day, but if you still have any algae hiding (have you done an overnight chlorine loss test?), it could drop more. Like I said for CYA of 50, your should be safe swimming up to FC of 20. But it sounds like your CYA could be higher ... at CYA of 60 shock is 24ppm.

I would still say bump up to about 20ppm today and tonight ... do the overnight test tonight to be sure nothing is living ... if you pass maybe don't bump it up tomorrow and let it fall before Friday. If you still get a significant FC drop overnight, bump back up to 20ppm for tomorrow also.

As long as you have clear water, less than 0.5 CC, pH in range, and FC < shock value, the water should feel fine.

Thanks, I will get started this afternoon.