Using Trichlor the CYA is high, convert to liquid chlorine?

Jump to latest Follow Reply
K

kh23838

0
Aug 21, 2017
2
Houston, TX
Hello-

I'm a rookie pool owner of about 6 months now. Currently using Trichlor tabs in the tube feeder. Was testing with the Pentair Rainbow 78 which just tests for Cl, pH, and TA. Chlorine levels are low, then I shock, of course the level goes up, but then drops over the course of days to 1.0. Start over with the shock, etc...Same results. pH is always good at ~ 7.4. TA is stable at about 90-100. After reading some threads on here and educating myself a little on water chemistry, I purchased the Taylor FAS-DPD 2006 test kit. With the addition of the CH and CYA tests I see now that my CYA level is way above 100. As I understand it, the CYA level being so high could be the cause of the Cl level being low. Am I correct? I also understand that I need to drain my pool by about half to get the CYA level down. My fear is that after I drain and refill, and get my chem levels sorted out, the CYA will just go up again if I continue to use the Trichlor. If this is true, should I convert to liquid chlorine?

Thanks.
 
Welcome to TFP!:wave:

Remember, 100 is the limit of the test, so we don't know if your CYA is 100, or some much higher number. Mine tested at 100 and when I did extended testing I found it closer to 250. So, yes to get the CYA down you need to drain water. But, don't be surprised that after a big drain you are not still close to 100.

CYA does not "cause" lower chlorine levels. Organics in the water cause FC to go down quickly. You need to conduct an Overnight Chlorine Loss Test to see if something is consuming the chlorine.

You are correct, you need to stop using pucks and granular shock. Both are almost 50% CYA and are driving your numbers higher. You need to use liquid to get the FC up to where it should be using the [FC/CYA][/FC/CYA]
 
Welcome to TFP!

You're on the right track with getting a FAS-DPD kit. First things first, at this point you don't actually know your CYA level, as you say it's "way above 100" because that's the highest the measurement goes up to, so we really don't know if it's 140 or 160 or so on... You'll need to dilute your pool water with half fresh water, tap water is fine, then preform the CYA test like normal but double the reading. Once we know your CYA level we can suggest how much to drain and fill and further the required FC level.

You'll definitely need to switch to liquid chlorine as any tablets are going to just keep increasing CYA.

I'm confused by what you're saying about your FC level. If you have been using tablets and can't maintain FC level above 1.0 ppm that probably means you have something going on in there that is consuming the chlorine. Normal daily usage is around 1-3ppm of free chlorine per day.
 
Thanks ! I will perform the overnight test but cannot get to it until this weekend. According to the FC/CYA chart, a CYA level of 40 shows that the target FC is 5-7. I thought 2.0 was about the normal, safe level. Am I way off on this? Also, if I convert to liquid chlorine, do I need to do anything to the tube feeder other than remove the pucks and turn it off? And do I then need to periodically need to add some sort of stabilizer?

Sorry for all the questions.

-kevin
 
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply