Need some help CYA high and New to testing

[onedah]

All,

I finally got my test kit and completed my first round of testing, results below:

FC - .05
CC - 1
pH - 7.2
TA - 60
CH - 400
CYA - just under the 100 line

So not sure what to do next - the CYA test only records to a max of 100 is the correct?
If so, when I tested the test come out at around the 100 mark - on 3 attempts I got reading of just under a 100, 100, and 90.

Pool water is crystal clear

In addition- I am seeing Algae form on the walls every few days.

Help on next steps would be appreciated.

Thanks

 

[pwrstrk]

Your FC is extremely low and your CYA is very high. That's where the algae is coming from. I would SLAM the pool, but also do a partial drain refill to get your CYA down or your going to use a boatload of bleach to SLAM.
Plus you have a CC of 1

pool-school/shocking_your_pool

pool-school/chlorine_cya_chart_shock
Have you been using pucks for your chlorine ?

 

[onedah]

I was using pucks - but stopped 2 weeks back. I have already drained about 50% of the pool and refilled. this was because leslie said CYA was 150.

Do I drain 50% again and refill before SLAM?

 

[pwrstrk]

Trust your testing. Is that CYA result from your test after the drain refill?

it could have been even higher when the pool store tested.

 

[onedah]

Yes the CYA test was done today and I did the drain and refill last week.

So it sounds like another drain and fill.

Am I correct in assuming that the CYA test only goes to 100?

 

[pwrstrk]

If its one of our recommended test kits yes, it reads to 100.

If your CYA is still that high I would drain some more to get it down. The pool store usually gets the CYA wrong. If you were using pucks for awhile that adds CYA.

 

[onedah]

Yep I am using the TF 100. It arrived today.

I am draining as I type - I think I may need to drain 60% does that sound right?

Should I also be brushing the walls before I refill?

Hopefully I can SLAM tomorrow...

 

[Wildcat]

If its one of our recommended test kits yes, it reads to 100.

If your CYA is still that high I would drain some more to get it down. The pool store usually gets the CYA wrong. If you were using pucks for awhile that adds CYA.

Read the extended test kit instructions on the forum. There is a way by diluting with half tap water to measure CYA over 100. Slightly less accurate overall but you can readCYA over 100 that way

 

[onedah]

I used the extended kit instruction.

My CYA reads at 120.

 

[gtemkin]

I am draining as I type - I think I may need to drain 60% does that sound right?

I used the extended kit instruction.

My CYA reads at 120.

You should be using the http://www.poolcalculator.com website to determine your dilutions and chemical additions.

To determine the dilution, go to the site, fill in 17500 (no commas) into the size field and then go down to the CYA fields and input 120 in the Now column and 50 in the Target column. You don't need to input any other items if your just concerned about CYA right now. Hit your return key to make sure your browser has accepted your inputs, and to the right of that area it should tell you the percentage of dilution you need. When I did it, it came back with 58% which is almost spot on with what you guessed.

Start playing around with the poolcalculator and get familiar with it. It will answer most of your chemical addition questions.

 

[onedah]

Thank gtemkin

I went for the 58-60% drain and now refilling.

I will test again in the AM and if all is good, I will start the SLAM process.

 

[Jeetyet]

So, if your 120 number is pretty close to accurate (and it should be) and you'd already drained 50% previously, then you started at about 240. Gotta luv them puck pushin' pool stores!

 

[onedah]

So, if your 120 number is pretty close to accurate (and it should be) and you'd already drained 50% previously, then you started at about 240. Gotta luv them puck pushin' pool stores!

The worse thing is that the week before I was told my CYA was high by the store they told me it was 50.

Shows how inaccurate their testing is but also that those Dam pucks are a waste of time and money. No way I'm going back to pucks.

 

[onedah]

So I drained my pool and refilled last night, about 60% - 70% drain. The new results as of the now are:

FC - .05 (if not lower)
CC -
pH - 7.2
TA - 50
CH - 170
CYA - 50 (hopefully I'm doing this right - looking down the tube can be a little hard to tell when the dot disappears)

Next I think I need to start adding Clorhine to start SLAM process. According to the Pool Cal I think I need 511 oz.

 

[RobbieH]

That CYA number is good! Congrats! Now get that FC up quickly with some bleach.

 

[onedah]

Great 2 questions

1. I can start the SLAM process?
2. Will I need to backwash? just did that last night and added DE the am?

Thanks

 

[RobbieH]

You can get started!

You just have to watch the pressure on the filter. If it raises to 20-25% over clean PSI, then you'll have to backwash. It is not uncommon to need to do so during the SLAM process.

 

[linen]

FC - .05 (if not lower)

Did you do this calculation right? If you used the 10 ml sample size, then you multiply your number of drops by 0.5 not 0.05 (there was a mistake in the printed material that went out with some of the tf-100 kits).

 

[onedah]

Yes I think I did something wrong - the FC is 0.5

I have started to SLAM -

Do I wait and take a reading in 1 hour to see the FC and CC levels? or take one now?

 

[duraleigh]

Do I wait and take a reading in 1 hour to see the FC and CC levels? or take one now?

Wait an hour. Actually, you can skip the CC's test if you like because it will perhaps go up and down at seemingly random and that's part of the process.

I would just check FC and bring it back to slam value or a bit above each time after you test. Testing and dosing carefully will keep your FC very precise and you will soon be able to lengthen out your time in between test/dose as the pool consumes less chlorine.

As you approach the point where you think you may be ready for the OCLT, then restart the CC's test. Crystal clear water will be your first indicator.

Run the pump 24/7 backwash/clean/brush/vacuum as often as needed. You're on your way!