UK SLAM FC level measuring

[BoringDamo]

So my first thoughts with this test kit is that the chlorine test for <10ppm is not great for pools.
The instructions for use are
0-5ppm — 40ml source — ppm = drop x 0.2
5-10ppm — 20ml source — ppm = drop x 3

The granularity is too coarse at 5-10ppm as you can only hit 6 or 9ppm with that factor.
I did email the chemist who responded with (my summarisation)
“As a rule double the source halve the factor. BUT for CL2 (the reagent in the test) at these levels it doesn’t work like that and the ranges are limited because it’s so dilute hence 0.2 for 40ml 0-5 and 3 for 20ml 5-10.
If you use 40ml at 5-10ppm then the factor should be 1 to 1.5”

Obviously that’s not great as that last comment leaves a 50% difference in results!
So at the moment I don’t have confidence in the results as an exact measurement but think I can get near enough for this season until I can find an alternative.

(Interestingly I was just experimenting and think I have around 9ppm FC based on dpd1 tablet comparator and the 20ml CL2 test and found using 30ml source with CL2 seemed to be pretty much 1 drop to 1ppm. However this is not scientific and probably just a coincidence for these values I’m at now!)

 

[BoringDamo]

Lovibond is a European supplier of water testing kits and equipment. They have several products based on xylene cyanol which is normally used as a low pH indicator dye or in gel electrophoresis (DNA testing) for indicating DNA size sorting. I suspect your supplier may be getting it through them.

Both Lovibond and LaMotte sell pool testing products in Europe. You could always check what's available from them.

So I’ve been doing more googling as I wasn’t happy with the ranges or confident in the results of the kit I got.
I suspect you are correct on the Lovibond thing after all.
I found this LR Free Chlorine drop test kit https://www.lovibond.com/ix_pim_ass...s/MA-K22101-KW_Chlor_frei/MA-K22101-KW_gb.pdf
Slightly different measuring but close to mine and all with chemicals “Labeled” CL1 for buffer and CL2 or CL3.
I then found KS152 - FCL2 - Free Chlorine LR Titrant _ _ RGT Xylene Cyanol 0_06pc which confirms the CL2 (KS152-FCL2) is xylene cyanol which was the name the chemist gave me.
Interestingly the first pdf I linked had much better granularity and ranges for what I need.
I’m going to try to see if the chemist can confirm “their” system is this but I’m tempted to follow the lovibond instructions and compare against the dpd1 tablet method I’ve got too which is hopefully close on <10ppm.

 

[BoringDamo]

Back to square one. Chemist says he is not 100 percent sure their concentrations are the same as what Lovibond ones are. (Which confused me as I gave the Lovibond ones from their SDS and the chemist should know their own). Anyway, I’m now not confident in this system so the search continues.

 

[bumblingbee]

Hi @BoringDamo how are you getting on with the Scuba 2? I have had my pool up for 2 weeks now and both my test kits are DPD1 / free chlorine only so I have no idea whether I'm getting any combined chlorine build up so need to find something fairly quickly to make sure it's safe. Did you see this test kit at all on your searches which covers free and combined? It only goes up to 5ppm so probably not useful for SLAMing. Balanced Water Test Kit - Chlorine (BWK145 Total Pool Brand)

 

[BoringDamo]

I think it’s @UKjames who has the scuba 2.
That kit is almost identical to the one I got and talking about in this post. However that kit is more expensive than I paid and mine included the extra FC tests (which aren’t worthwhile).
Im thinking about ordering the Lovibond agents for the same xylene cyanol based FC test as they seem to have more range and granularity than mine but it’s £60 which is a lot.
(Lovibond Chlorine (Free) LR Reagent Pack)

 

[UKjames]

I have a lovibond md110 with I think 6 tests- FCl, ph, cya, cah, ta and bromine. I have the high reading dpd1 tablets that enable reading of FCL up to 10 ppm and dpd3 ones for Total chlorine. It seems to work pretty well day to day but would be more of a faff for a SLAM as you’d need to dilute the sample to get a reading above 10.

I had to do this initially when trying to work out what the CYA level was as it was off the chart

The MD100 is the same I think but doesn’t have Bluetooth connectivity. You can get cheaper variants with fewer tests too.

In the absence of A Taylor’s kit it works well enough so far

I did look at the scuba 2 but it didn’t seem to have that great reviews from memory. Looking back I don’t know how much of this was down to the device or user error or ignorance of their CYA level and thus they had no reference point to set their FCL

 

[BoringDamo]

Back to square one. Chemist says he is not 100 percent sure their concentrations are the same as what Lovibond ones are. (Which confused me as I gave the Lovibond ones from their SDS and the chemist should know their own). Anyway, I’m now not confident in this system so the search continues.

So an update on this one. Having not been confident in the WTP kit I ordered the Lovibond LR reagents to follow their instructions (as posted above) as that gives more granularity. It’s taken a while to turn up so in the meantime I’ve been using the original LR chems but the Lovibond measuring alongside also testing using the dpd1 tablet method. As time has gone on I’ve become more confident that the agents in the original set were the same as Lovibond (contrary to the chemist suggestions they might not be) as the additions I was doing based on that testing and what poolmath said should happen tied up.
The Lovibond agents have now finally arrived and I’ve done a few tests using both original and new Lovibond reagents and the results are always exactly the same.
So in summary, that original test set is ok if you follow the Lovibond instructions not the instructions that come with it.
My Lovibond reagents also have a 2023 date on them so I’m now stocked for next year too!!

 

[UKjames]

Does that give you a FAS DPD free chlorine reading measured by drops? If it does I’d be interested to know which reagents you have.

 

[BoringDamo]

Does that give you a FAS DPD free chlorine reading measured by drops? If it does I’d be interested to know which reagents you have.

No it’s a different system, not FAS dpd but xylene cyanol and sodium something or other.
It is titration based though (count the drops).
I’ll find the link for the Lovibond reagents later once I’m back home.

 

[BoringDamo]

Back home….
This is the Lovibond LR reagents Lovibond Chlorine (Free) LR Reagent Pack
(Lovibond pointed me to this site).
As you can see from the following it does allow testing up to 30ppm.

 

[UKjames]

Thanks. I did find the Taylor fas dpd reagents on eBay that look like they might ship to UK for a similar price to that (about 35 I think plus 20 shipping). Hmm will give it some thought!