Does Taylor R-0014 contain a chlorine neutralizer?

[sharknj]

Does anyone know if the Taylor R-0014 phenol red that comes with the PS234 kit contains a chlorine neutralizer? The reason I ask is that I'm getting a lower pH reading than I am with my other test kits. One kit is an unknown brand (OTO/pH drop kit) that was supplied by the PB. The other is a 4-way ACE Hardware kit manufactured by NEP/JED Industries. The phenol red in the unknown kit states that it contains a chlorine neutrolizer. The ACE kit contains a separate bottle of neutralizer, though it doesn't say what chemical it is. No ingrediants listed on their websire either.

I checked the MSDS for the R-0014 http://www.taylortechnologies.com/MSDSS/0014.PDF and it doesn't seem to mention anything other than phenol red. I have an Aquarite SWG so I rely on a correct pH reading to know when to add muriatic acid. Here are my numbers with the PS234:

FC 5.5
CC 0
TC 5.5
pH 7.2
Alk 90
Cya 40
temp 74

The other kits are giving pH readings of 7.6. I'm tempted to go with the Taylor reading simply because of the Taylor name, but I'm a little concerned about the lack of neutralizer listed on the MSDS. Would the MSDS normally list this?

Thanks,
Steve

[CarlD]

It is supposed to. I think the num 7 solution is neutralizer

[waterbear]

The chlorine neutalizer is sodium thiosulfate (plain photographer's hypo for anyone that ever had a darkroom). If I understand correctly the Taylor reagent already contains enought to work properly up to about 15 ppm chlorine. From my own experience the phenol red in the Aquachem kit works up to about 10 ppm. The first reagent in the ALK test in the Taylor kits (and Ben's) is sodium thiosulfate and if you are getting fasle high pH readings from high chlorine levels you can try adding a drop or two before the phenol red. The results will be more accurate but still have some error since the sodium thiosulfate itself can change the pH of the test sample.

It is entirely possible that it is not listed in the MSDS since they are only required to list the main indgredient and any "dangerous" chemical in a product There is really very little added to the phenol red. On some MSDS no ingredients are listed at all and it just says "Propriatary Mixture"
Sodium Thiosulfate itself is pretty safe...here in an excerpt from a MSDS for it in crystalline form
Potential Health Effects
----------------------------------

Inhalation:
May cause irritation to the respiratory tract. Symptoms may include coughing and shortness of breath.
Ingestion:
Low level of toxicity by ingestion. Diarrhea may occur by ingestion of large quantities.
Skin Contact:
Irritation may occur from prolonged skin contact.
Eye Contact:
Contact may cause mechanical irritation.
Chronic Exposure:
Chronic exposure may cause skin effects.
Aggravation of Pre-existing Conditions:
No information found.

Now this is the same section from a MSDS for Sodium Chloride (commen salt). You can see that salt causes much more severe problems when ingested, gotten in the eyes, or absorbed through the skin than sodium thiosulfate! (but don't eat or drink the chlorine neutralizer!)
Potential Health Effects
----------------------------------

Inhalation:
May cause mild irritation to the respiratory tract.
Ingestion:
Very large doses can cause vomiting, diarrhea, and prostration. Dehydration and congestion occur in most internal organs. Hypertonic salt solutions can produce violent inflammatory reactions in the gastrointestinal tract.
Skin Contact:
May irritate damaged skin; absorption can occur with effects similar to those via ingestion.
Eye Contact:
Causes irritation, redness, and pain. (For salt concentrations greater than the normal saline present.)
Chronic Exposure:
No information found.
Aggravation of Pre-existing Conditions:
No information found.

[Amir]

Steve,
your variation in ph reading between the two tests are the same variation I am getting using a digital ph meter. (see the post for Henna PH meter) I have ordered new calibration solution to finally put this question to rest. The only problem is that the buffer will not have any chlorine.
Amir

[sharknj]

Waterbear, I figured the MSDS might not list everything but I wasn't really sure. I haven't had the pleasure of reading too many of them! I see what you mean about how they can make something sound a lot worse than it really is. So the lack of a neutralizer could give a potentially false HIGH reading? The reading I'm getting with the Taylor pH is actually lower than the numbers I'm getting with my other test kits. Thanks for the tip on the first Alk reagent. I'll take some readings with and without a drop of the sodium thiosulfate to see how it affects it.

Amir, I'm interested to see what you find out with the new calibration solution. I'm really hoping that you find that your meter ends up matching the Taylor pH after all.

[sharknj]

Well I tried adding a drop of the Alk #1 before the 5 drops of phenol red and now the Taylor kit reads the same as my other 2 el cheapo test kits. Without the Alk# 1 it still reads about .3 lower. Sooo... either the Taylor kit reads low and the cheap kits are right, or the Taylor kit already has sodium thiosulfate and adding a drop of the Alk #1 is doubling it up and causing a false high pH reading. If this is the case, the cheap kits are also giving high readings.

I think for now I'm going to trust the Taylor kit, but err on the side of caution and add muriatic acid whenever the pH reaches 7.5. I'll just be adding smaller amounts a little more frequently. This is probably better anyway since it will keep the pH from swinging much, and keeping it low (7.2 - 7.3) should help the SWG anyway. Even if it turns out the Taylor pH really does read low, the worst I'll be doing is keeping it around 7.5 - 7.6 which still isn't too bad, right?