CYA zero?

[perilous]

Just opened...using TFP Test kit...it appears CYA may be zero (black spot in tube never grays out even when tube is full!). Can that happen in one winter? If so, assume this is first thing to tackle or should I start putting bleach in pool immediately (green), OR deal with high ph first?


Current NO CHLORINE; no apparent CYA, PH 8.2+ and TA 7

When should I SLAM...now or later?

 

[Mr Bruce]

Get pH down first, then it's SLAM time!

(e: bleach and CYA can go in at the same time once pH is down)

 

[JVTrain]

Lower pH to 7.2 first, then hit it with some bleach, targeting 10 ppm. See if you can measure anywhere near that FC after circulating and brushing for 10 minutes, then get back to us with your results. Measure FC and CC only after 10 minutes.

 

[perilous]

Lower pH to 7.2 first, then hit it with some bleach, targeting 10 ppm. See if you can measure anywhere near that FC after circulating and brushing for 10 minutes, then get back to us with your results. Measure FC and CC only after 10 minutes.

OK..FC 0.5 and CC 4

 

[JVTrain]

You're unable to hold FC and your CC is climbing rapidly. This means you likely have an ammonia issue due to your CYA being converted to ammonia over the winter. What you should do at this point is keep doing that process until your FC holds at nearly what you targeted 10-15 minutes after adding. So... keep targeting 10 ppm with your additions, testing every 10-15 minutes after dosing for FC and CC. This is burning through the ammonia. Ammonia reacts VERY quickly with chlorine so your FC will not hold and your CC values will rise until all the ammonia has been oxidized. Then you will be able to measure an FC greater than a few ppm.

You're going to need quite a lot of bleach, depending on how much ammonia you have...

Also, did you add acid and remeasure pH?

 

[perilous]

You're unable to hold FC and your CC is climbing rapidly. This means you likely have an ammonia issue due to your CYA being converted to ammonia over the winter. What you should do at this point is keep doing that process until your FC holds at nearly what you targeted 10-15 minutes after adding. So... keep targeting 10 ppm with your additions, testing every 10-15 minutes after dosing for FC and CC. This is burning through the ammonia. Ammonia reacts VERY quickly with chlorine so your FC will not hold and your CC values will rise until all the ammonia has been oxidized. Then you will be able to measure an FC greater than a few ppm.

You're going to need quite a lot of bleach, depending on how much ammonia you have...

Also, did you add acid and remeasure pH?

Yes...sorry...got it to 7.2...

 

[JVTrain]

No biggie, just wanted to make sure you dealt with the pH now so that when/if FC/CC levels climb higher, you know you got the pH in range first. The pH test is unreliable at FC/TC levels 10 or higher.

 

[perilous]

Thx!!!

 

[JVTrain]

If you have time, keep on posting FC/CC results as you do them. I'm always curious with these potential ammonia situations how high the CCs climb and how quickly the ammonia can be consuming FC.

 

[perilous]

OK...ten-fifteen minutes...FC 5.0 and cc 0.5!!

 

[Mr Bruce]

It won't take more than a few cycles of that and you'll be holding.

 

[JVTrain]

Well that was quick! Try to get it up to 10 ppm with the next dose. If you hit that or almost, then it's time to get some CYA in the pool and continue with the SLAM. Use Pool Math to figure out how much CYA you'll need to hit 30 ppm CYA. Add that by putting it into socks and put the socks either into your skimmer basket or hang them in front of a return. Then you assume that your CYA is 30 and target 12 ppm for your SLAM.

 

[perilous]

Well that was quick! Try to get it up to 10 ppm with the next dose. If you hit that or almost, then it's time to get some CYA in the pool and continue with the SLAM. Use Pool Math to figure out how much CYA you'll need to hit 30 ppm CYA. Add that by putting it into socks and put the socks either into your skimmer basket or hang them in front of a return. Then you assume that your CYA is 30 and target 12 ppm for your SLAM.

Last reading fc 9.5 and cc 0.5...on way! Looks like I was lucky and got it right away...

Because my ph was high and cya low, I used dichlor shock (read that it raises cya and lowers ph in pool school so said why not use it!) for first 2 shocks vs. bleach...cya is now 20-25 and ph (with ph down too) got to 7.2 pretty quick...so I think I will SLAM from here...all liquid bleach from 2 shocks ago!...water still green but chemistry seems good, just backwashed as well...

thx all and wish me luck!!

 

[JVTrain]

It's best for newer folks to just be using bleach, but if you understand what dichlor will do to your chemistry (changing THREE parameters at once!) it can be useful in certain situations. Sounds like you're on your way.

 

[perilous]

OK... left overnight...FC holding at 12 and CC at 0.5...so chemistry looking good! So just to confirm...keep an eye on things, maintain shock level at 12, brush regularly, backwash as needed, and wait for pump to do its work and get rid of green/grey?

Thx!!