CYA off the chart

[CAW]

Greetings,

I'm new to Trouble Free Pool but have had great results over the past 3 yrs I've owned my pool. I enjoy the posts tremendously, been learning a lot but have a question about dealing with CYA in the 200-250 range. I've been reviewing the CYA/Chlorine charts and trying to really wonder if I should get my FC up to 39 to really shock this thing or try and drain instead.

My question is can I deal with this high FC and shock levels all summer or should I try to drain/fill 6-10 inches of water several times until I can get CYA down?

I've stopped my stabilized chlorine pucks for about 3 weeks now. I know how I got this high CYA it was by dumping too much Bioguard Smart Shock when I first opened up trying to clear the water fast. I have beautifully clear water but just scared of the high levels of chlorine I'll have to maintain to reach the shock level due to the high CYA.

Today's results after 2 gals of 12.5% shock last night
FC 8.6
TC 9.9
TA 130
PH 7.2
Ca 125
CYA -- using the diluted method and multiplying by 2 I'm at least 200 - 250 using the LaMott Colorq

Any advice would be greatly appreciated.....and thanks for your time!
Chris

 

[JasonLion]

Definitely replace water to get the CYA level down. Just keep in mind that CYA might actually be higher than you think it is (or perhaps lower). All of the tests become very imprecise when CYA is that high.

 

[CAW]

Would you agree to try and do this in stages of 6-10 inches at a time? I don't know if the liner could collapse in if I go a lot at a time? I'm talking about closing levels (just below skimmer) and then refill and repeat.

Thanks

 

[JasonLion]

If the soil is normally dry, then 12-18" is usually fine, but if the soil tends to get boggy then you might want to limit it to 6" at a time. If you know your water table is fairly low then you can drain further. In any case, with a vinyl liner you always want to leave a minimum of 8 to 12 inches of water in the shallow end.

Draining and refilling a little at a time, or even both at the same time, is fine. It ends up using a bit more total water, but is safer for the pool and often easier to do as well.

 

[CAW]

Sounds good. Appreciate your quick response and wealth of knowledge.

Thanks for your time.
Chris

 

[CAW]

After about a 6 in level drain and refill, my tests today show

FC 6.7
TC 7.4
PH 6.9
TA 74
CH 54
CYA -- best estimate is 188, Colorq shows 89 at 1:1 ratio with distilled water

I'm guessing I'll need to do this drain/refill many more times unless I go more than just below the skimmer (inch or so). Oh, and I did notice that the liner is fading (bleaching) from that level drop. Stupid pool store telling me to use the pucks (Bioguard 1-2-3 method). Gives beautiful water clarity but they never once talked about CYA--they have no clue.

Thanks
Chris

 

[JamesW]

It might be easier if you get a small submersible pump to pump out water, and refill with a garden hose at the same time and at the same rate. That way, the level never drops, and you can start and stop the process at your convenience. You can even get an autofill device that will keep the pool full as the small submersible pump works.

 

[CAW]

Good idea James...thanks Certainly more convenient than dragging the 100ft drain hose to the street at 11pm at night and waiting an hour for it to drop, then another 3 hrs to refill ;-)

 

[CAW]

Well, I've drained and refilled about 15 inches total (2) 6-8in sessions this week. I was consistently getting at/around 200 per the Colorq 1:1 diluted. By the way I just ordered a TF-100 kit with mag stir.

Still with the Colorq, I'm consistently getting an average around 135 ish, so I think I'm making some headway. I do have a question that I know what everyone will say (keep pouring chlorine in), but here goes.

I still have not been able to get rid of my CC. It's been < 1 but > .5 even after 8 gals of 12.5% over the past 2 days. I don't seem to be dropping > 1 FC overnight. At this high level of CYA will I really be able to get rid of all the CC or if I'm < 1 and > .5 is that "ok"?

Latest readings after 4 gals of 12.5% this morning

FC 13.6
TC 14
PH 7.4
TA 114
CH 130
CYA 135

Thanks again for your help!!!
Chris

 

[JasonLion]

Assuming CYA is really 135, you should be raising FC up into the 40s and maintaing it there to shock the pool to get rid of CC. With FC at 13.6 you are right around the normal day to day FC level, not anywhere near high enough to shock. 8 gallons of 12.5% should have raised the FC level up into the 40s. The fact that you have lost so much chlorine in only two days suggests that you are not nearly done with shocking.

 

[CAW]

Yep, as you know it's hard to be real sure with the Colorq, I need that TF-100 kit to get a better picture of my FC I think. I've kept everyone out of the pool this week and now the wifey is looking at me with crazy eyes cause she wants in the water. For now, I'll keep up with the partial drain another couple of times and wait for that TF-100 kit to arrive. I should have gone with that per your recommendations but wanted the fancy color meter instead :-(

Thanks for the quick response
Chris

 

[CAW]

Ok, I'm back once again for a Q&A about Colorq vs. TF100 and my results since I've been dumping water. I had a ColorQ for about 3 weeks and ordered a TF100 w/mag stir and have been using both over the past week.

If you recall I was estimating my CYA was at and/or above 200 on June 1. I've dumped about 6-8in of water 5 times now. My CYA with both the ColorQ and TF100 is hovering at 85-90 and I do these readings about 3 times each to make sure I'm averaging the results--I feel good about those results and think I'm heading in the right direction with my reduction of CYA.

My question is more on my chlorine tests results between the 2 kits. My TF kit always seems to be higher than my ColorQ. Today for example I've completed 2 tests, 1 about 9am and the other about 3pm and it's full sun today about 90 degrees.

ColorQ 9am FC 3.87, TC 4.01, CC .14
TF100 9am FC 6.5, TC 7.0, CC .5

added 1 gal of 12.5% chlorine about 10am

ColorQ 3pm FC 7.14, TC 7.34, CC .20
TF100 3pm FC 12, TC 12, CC 0

If my CYA tests seem to be so close between the 2 kits, why do you think my Chlorine tests are so different from each other? I've reviewed the extended testing recommendations and I have a mag stir I'm using only on the TF100 kit, I cap the tubes on the ColorQ and wiggle slowly left/right/up/down 3 times each.

By the way TA and CH seem to be close to each other on the kits, TA diffs of 5+/-, CH diffs of 10+/-.

As always, thank you for your time.
Chris

 

[yeggim]

I'd trust the FAS/DPD test. Testing before and after bleach addition the FAS/DPD is right on the money. All test are prone to errors but the titration method is used in a myriad of chemical tests so I'd have to assume it's more exact.