Insanely high CL levels, according to test kit(s)

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I

IPvFletch

0
Feb 24, 2008
79
Dripping Springs, TX
Hi, I've had my pool ~5 years now, and this year I am testing it after doing some maintenance and cleaning the filters, etc... I've never had any problems with it, and not once have had algae pop up (I'm quite proud of that!).

I use the CL tabs, of course, and so I know my CYA levels are really high. In fact I just did a test (using a TFP test kit mind you!) and it showed CYA levels in the hundreds, probably like 400-500 I'm estimating, since there's no additional hash markers on the vial.

I am also noticing my CL test shows ridiculously high CL levels. The color is more of an orange in fact. Well off the chart.

So I am thinking the high CYA level might be screwing up my CL test, is that possible?

I'm planning to drain the pool (soon) maybe down to 1/2 or so, and refill with new fresh water.

I'm not sure if I will continue using the CL tabs/pucks, because I like the convenience. I don't mind having to drain my pool once every few years (this will be the first time in ~5 years btw). I tried the BBB method for a bout 6 months but I stopped doing it. I can't remember exactly why I stopped, but I vaguely recall the liquid Chlorine is more expensive than the tabs, and doesn't last as long (I have to add CL more regularly, whereas with the tabs I can go for 1-2 weeks before I have to refill the cylinder).

Thoughts?? Criticisms? :D

Thanks!
 
Thoughts?? Criticisms?
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The convenience you find with pucks will be quickly eliminated once algae takes hold of your pool and you try to clear it.

BBB is not about using Clorox but it is about understanding the effects of all the things you add to your pool.

You seem to understand what the pucks are doing to your pool but you do not seem to understand the consequences.

If it's working for you, that's great and if you are not having any troubles, you really are practicing BBB and I wouldn't change.
 
The first thing that comes to mind is that the "TFP test kit" doesn't have orange as a color, and there is no off the chart. Unless you're using the OTO kit and if you are you need to use the FAS-DPD test. and post the numbers.
 
I got the same results with the Pentair kit and also the Taylor kit which was inside my TFT kit. The kits are pretty old, I wonder if the reagents are bad? In both cases, after adding the second drop of reagent, it began turning orangish. Basically more yellow than the darkest yellow.

I tried the FAS-DPD test twice and both times after I put the heaping spoonful in, it turned bright pink then went back to clear. Adding the 871 made it eventually go pink again but at this point I stopped because I knew it wasn't going the right direction (more pink, less clear).

Like I said above, I'm using pucks and have been for ~5 years. My puck feeder is around 1.5, it was at 2 but I lowered it thinking it was adding too much CL. I run through pucks in about 2 weeks, maybe slightly longer in the Winter, and shorter in the Summer/Spring. My CYA is off the chart - I know this.. My pH is right around 7.6.

I'm still thinking the CYA is screwing up these tests?

Also I haven't done a CH test recently, but it used to be high, and I'm sure it still is. We have limestone all around our pool (stone wall raised beam and also the coping including spa spillway into pool). I don't go to any pool stores and don't put any of their stuff into my pool. Just vinyl toys occasionally. :)

Otherwise my pool is great - crystal clear as long as I can remember, and never had any algae grow. It is uncovered and gets a lot of sun year-round. It also gets a lot of debris including grass clippings and leaves from my nearby wax myrtles. I clean the cartridge filters annually (actually just bought 4 new ones and put them in) and dump leaves from the scupper and polaris usually every week or two. No animals are living in my pool, that I'm aware of, but over the years I've found 1 dead frog, 1 live frog, and 1 small dead lizard in the polaris... Just trying to add any context which may help.. :)
 
If the FAS-DPD flashes to pink and immediately turns back clear as your adding powder you need to add more powder until it stays pink. It sounds like you have really high FC. I'd run the test again because I'd really want to know what the FC really is.
 
Thanks (for being civil, Bama Dave)...

I ran the FAS-DPD test again. I put in about 2 heaping spoonfuls worth in order to make it stay pink this time. It turned (and stayed) really dark pink. About like this.

I ended up having to put about 60 drops of 871 in there to make it turn (and stay) greyish/clear. That means 30ppm of Chlorine is in there? I kind of doubt that.. I get a lot of of debris like I said, and I'm sure there's microbes and pathogens galore in there. My puck feeder uses up about 10 tabs in 2 weeks, but I always had CL left when it was empty, although I always make it a point to refill it or check it weekly just to ensure it never runs out. I think it only lets so much in based on the dial, which is currently around 1.5 I think it was 2.5 over the winter..
 
I feel sure it's 30 ppm or a little higher. The FAS-DPD test is the most accurate test and it will test ot over 50 ppm FC. Did you happen to run the CC test while you were at it. I don't think you have any but it would be interesting to see.

No wonder you haven't had any algae! :)
 
That sucks.. That's also quite bizarre because I don't notice the smell of CL, and our eyes don't really burn if we open them under water. The pucks dissolve after like I said ~2 weeks, and I just add more. I guess I thought the puck feeder only let so little out that it kept it equivalent to 1.5 or 2ppm as per the dial's indicator. Apparently not.

Also, when I fill the puck feeder I notice if I fill it and then turn on the filter pump and then wait till the feeder fills with water, then close it, the pucks get used up more quickly. If I fill the puck feeder and then close it before I turn on the pump (which is a danger due to getting air trapped in the feeder stack) then my pucks are used up more slowly. But still anywhere from 1-3 weeks or so. I wonder if there is a correlation here. But I guess the bottom line is I need to measure FC (and ideally CC to get my total) before I put more pucks in on my weekly check. Does that sound about right?

I did my CYA test like 2 weeks ago when it showed ~400+ so I am certain I need to drain at least 50% or more and refill. I will probably do that pretty soon, maybe in a few weeks..
 
Actually there is a reason that the tablets dissolve more quickly if you purge the cylinder of air. If there's air in the cylinder thet tablets above the air aren't dissolving at all so only the ones submersed in the water are dissolving and they have to dissolve before the top ones get down to the water to start dissolving. Just because we don't use tablet feeders, doesn't mean that we don't understand them. :)

You definitely need to do a better job of testing.
 

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Right.. and maybe the air is a good thing as it prevents all of the pucks from being dissolved too quickly (which is likely what causes the high CL levels).. But it's annoying to have to gauge how quickly they dissolve now in addition to the dial setting in addition to how quickly the sun/UV and contaminents zap/use up the FC.. *sigh* Testing more often and at least during puck adds, is probably the only way to get this resolved permanently..

Is there anything I should do to get the CL level down to a reasonable amount? I suppose it isn't hurting anything, but I am not sure I like it that high.. Maybe a poolful of kids if all I need to bring it back down? :)
 
IPvFletch said:
Is there anything I should do to get the CL level down to a reasonable amount? I suppose it isn't hurting anything, but I am not sure I like it that high.. Maybe a poolful of kids if all I need to bring it back down? :)
Click to expand...
Our idea of reasonable FC levels is dependent on CYA levels. If your CYA level is north of 100, then FC of 30ppm isn't insanely high, it's perfectly reasonable.

Dave said it above, and I'll repeat here....it's your pool, and if it works all power to you. However, this is the exact reason why we don't chlorinate exclusively with pucks. Once CYA gets above 100, there's a ton of guesswork involved, and the TFP philosophy does not comingle with guessing.
 
I am just going to add that when the FC > 10ppm (which it sounds like you always are), the pH test will read artificially high.

With the amount of pucks you are using I would have to think the pH and TA are very low, unless you are adding something to try to counter that (and as I stated, you can not test pH accurately with the high FC).

"High" FC does not result in a chlorine smell or sting the eyes ... it is the CC that cause the problems.

What you need to grasp is the FC/CYA relationship: pool-school/chlorine_cya_chart_shock

From the chart if your CYA were 100ppm, the minimum FC to prevent algae is 7ppm .... extrapolating .... if you think you have 400ppm of CYA, then your FC minimum should be 28ppm to prevent algae.

We state that it is perfectly safe to swim with FC up to shock level. For a CYA of 100ppm, that would be a FC of 39ppm (according to the chart). If you had 400ppm CYA, then we would way it is safe up to a FC of 156ppm :shock:

In reality this would still have a lower "active" chlorine level and be less irritating and damaging than a public pool with 0 CYA and a FC of 2ppm.
 
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