Trouble getting CC to zero.

[duraleigh]

Huskerfan,

I'm a little confused by your CC's? How are you measuring .4 and .6 values? I am not aware of a test that precise.

[chem geek]

Dave,

The FAS-DPD chlorine test can measure Free Chlorine and Combined Chlorine each to 0.2 ppm since using a 25 ml sample size has one drop of titrant measure 0.2 ppm (the 10 ml sample size has one drop measure 0.5 ppm). You add 2 dippers of R-0870 powder which makes the sample turn pink if free chlorine is present, then add R-0871 dropwise until the sample turns colorless. The count of drops is Free Chlorine. Now you add 5 drops of R-0003 and the sample will turn pink if combined chlorine is present, then add R-0871 dropwise until the sample turns colorless. The count of drops (after adding the R-0003) is Combined Chlorine.

Richard

[duraleigh]

Thanks, Richard,

I had fogotten about doing that test with 25ml. Makes perfect sense to me now. (Tho, I'd have to say, that precision seems like a little bit of overkill)

Nevertheless, I understand now.

[huskerfan]

It's definitely overkill if your pool is at shock level! When it's not it doesn't take that much longer or that much more reagent. I was told .4 cc is acceptable, .5 or higher - shock, thus I measured with the 25ml level. LOL - I guessed .6 on my cc now, it was just barely pink after adding one drop of 0871. It actually could have been .7 or up. Sometimes you just gotta guess .

Richard, I was told to only use one dipper of the DPD powder regardless if you were testing using the 25ml line or the 10ml line. Quite possibly I was told wrong, but it was from a very reliable source. You're absolutely right on the aeriation, but for now we're starting our planting season and didn't have the time to hook up the fountain, and too cold for these bones to jump in! The borax was handy and quick. My TA is a little high, but I read it's ok as long as it stays under 180. It'll drop as we start to swim too --- that's those times when I need a little muratic acid as my daughter is 10 and we have her friends over a lot - so it gets a lot of aeriation!

Will check the chlorine and cc levels once more before going to bed - will let it come down and get my solar blanket on tomorrow. When you fill with iron filled well water you don't want evaporation either.

Matt 4x4 talked about a brown dust algae where he had to overshock to get rid of it... wonder if that's what mine is. I don't think I want to shock over, let alone up to 19 again, as I don't want my iron to fall out.

After my chlorine drops to my normal rate I'll recheck my cc using the 25ml line and repost the actual number. I think I'm just gonna have to live with some cc in our pool. Thanks again!

[chem geek]

The Taylor instructions say to use two scoops and somewhere else on this forum (if I remember correctly) somebody experimented with differing numbers of scoops and some people got slightly different results. With my own testing, I found that it didn't seem to matter at the chlorine levels I was testing, but as a general rule I think it best to follow Taylor's instructions as can be seen at this link for the K-2006 kit.

Your higher TA is perfectly fine since you've got a vinyl pool so can have lower CH (which you have). The only issue with higher TA in your situation is a tendency for the pH to rise, but you don't see that because you keep your pool covered (with a solar cover) and probably don't have aeration features (fountains, waterfalls, etc.). If you had an SWG, then the higher TA would likely cause a very large rise in pH.

Richard

[ivyleager]

FYI,

I just purchased reagents and DPD-FAS powder directly from Taylor, which I would recommend over going thru this site. I received them in 2 days!

Anyway, the scooper for the Taylor powder is TINY! I can see why their directions may state to use 2 scoops. It's MUCH smaller than the one included in the poolsolutions kit.


CaryB

[huskerfan]

If I read it correctly the Taylor instructions say to use 2 scoops of DPD powder regardless of whether you're using the 10 or 25ml line. The directions pasted inside my PS233 Testkit from Ben says to only use 1 scoop- but only gives the directions for the 10ml line. With now knowing the dipper is a lot smaller from the Taylor kit, that would make up for the one scoop difference on the 10ml line, but I was still told to only use 1 scoop on the 25ml line too. Obvious thinking would be to add 2 scoops for the 25ml line - but was told to still just use 1. Sometime I'll do it both ways, after my chlorine level comes down. I actually just went and got my last sample for tonight, and tried the 10ml line both with 1 scoop and 2 scoops from Ben's test kit. Both readings were identical for both TC and CC: 16 for TC and .5 or under for CC.

Also- referencing the CYA with both listed above - Taylor's says to cap & mix for 30 seconds, while Ben's says to cap, mix, and wait 30 seconds, which I take as letting it rest for 30 seconds after you mix it before pouring it into the tube. Maybe I'm interpreting this wrong?? I have been known to be wrong once or twice in my life, lol! So which is correct - or maybe it doesn't matter either??

I prefer to give my business to Ben, but if in a pinch it's nice to know the reagents can be gotten elsewhere quicker. Please note too: my DPD powder is med. gray from last year and some of my other reagents 2 years old, so realistically my readings might be off because of that. But a post I read where Poconos did some experimenting with darker out dated DPD powder I believe, if memory serves me correctly, says he got the same results with the old and the new.

Wish my cc would have dropped more- but maybe my pool will never get to 0cc. The last summer and 1/2 (this is my third season with our pool) I always had .4cc, never 0. I have a lot of trees on two sides and a cornfield a little ways away from 1 side. Nebraska gets a lot of wind which blows around pollen and dust. I'm pretty anal at keeping my pool very clean, but you can't always see all the contaminants either. We haven't died yet- and our water doesn't smell and is crystal clear and feels good, so I guess I'll keep doing what I have been doing and just enjoy it . Happy Swimming all.