Super high CYA--please confirm what I need to do next

[Drfos]

I just received my new TF-100 test kit and did the testing this morning. Here are the results:
TC 5
FC 4
PH 6.8
TA 170
CH 400
CYA 150

I plugged these numbers into the pool calculator and was told to make the following adjustments:
--add 57oz of washing soda OR 109oz of borax to adjust the PH
--replace 73% of water with new water to adjust the CYA (a different amount of water replacement was suggested to adjust the TA--like 35%)??

We "rebuilt" an old pool 2 years ago so all the water was replaced at that time. We have had a pool for 20 years and ALWAYS used dichlor. I don't know why we are having this problem now after all that time of using dichlor without issues. I have been using pretty much only liquid chlorine bleach for the past month or so with occasional pucks.(I was trying to increase the CYA level per my test strips!!)
I had been testing multiple times per day since we opened the pool over a month ago, trying to figure out the problem with cloudy water, dead algae and no FC. I was using the Aquacheck test strips and I have been getting a TC of no more than 3 and a FC reading of 0-0.5ppm FC even the day after shocking the pool with up to 6 gallons of 10% bleach. Maybe the strips were old but they shouldn't be--can't decipher the date on them. Anyway, I won't be using those anymore. But I can't believe that the CYA readings on the test strips AND at the pool store were SO far off--pool store gave me a reading of 70ppm two different times.
My question is how to get out of this mess. I'm having a confidence problem with trusting the TF-100 CYA results when everything else was telling me it was much lower.Please list the steps going forward--I'm guessing we need to drain about halfway down and then test again and adjust the chemicals. I HATE draining the pool. We live in Wisconsin and it was just getting warm!

Please help--I need the experts to weigh in and rebuild my confidence in managing my pool!

 

[jblizzle]

Welcome to TFP!!!

And this is why we do not trust pool store testing OR test strips.

You need to replace at least 50% of the water to lower the CYA. Leave at least 1 foot of water in the shallow end. If you have a very high ground water table, then you may not want to do all 50% at the same time and might need multiple smaller drains.

After you fill up and circulate the water for at least an hour, then retest everything.

 

[BuckeyeChris]

Did you get the 150 number by doing the CYA test diluted with tap water?

 

[Drfos]

Yes, I followed the directings for the "fading endpoint" and multiplied by 2.

 

[jblizzle]

The CH has the fading endpoint ... not the CYA

 

[BuckeyeChris]

you can start your CH test with smaller samples and use a different PPM per drop calculation, like you would with a 10ml vs a 25 ml FC test. No multiplying at the end though.

THe cya test, you fill the vial to the 7 oz mark with pool water, fill to the second 14 ml line with tap water, mix well, then pour out half to get the water line back to 7 ml.

Then continue the test by adding the r-013 to get to 14 ml, mix for 30 seconds, then add to the tube. When you can no longer see the dot when you glance at it, you take your reading and multiply by 2.

 

[Drfos]

Oh, yes...thank you for correcting me! I did it both ways--first the usual way and then verified my results by diluting it with tap water and multiplying by 2.
This pool chemistry is new for me--I appreciate learning from you all.

 

[Isaac-1]

One more thing, can you please add a state to your location, it helps us know your local climate and give better advice (The advice we might give someone in North Dakota with a 2 month swim season is different from someone in Florida with a 10 month swim season, etc.