OTO vs DPD vs FAS/DPD

[Mattikuss]

Hi Friends,

I'm reading back on old posts from 2012 and just want to get this straight on one post. Can someone clarify these tests for me?

OTO, my understanding, is the test with the yellow for Cl and Red for pH. In my TF-pro test kit it says that this is a daily test but people on TFP are slamming (pun intended) it as being useless. The other issue that I see with this test is that it seems to be limited by pools with healthy CYA levels, in that our Cl levels will be higher than 5ppm (the limitation of the test).

FAS/DPD - Everyone seems to be raving about the FAS/DPD which I believe is the 10mL of pool water with those little granuals, then add the big bottle drop by drop until it is clear. There is the option to also test for CC with this test. I find that I am doing this more than once per week which is what my TF-Pro test kit recommends.

DPD - What is this?

 

[dfwnoob]

Personally, I never use OTO or DPD-only. I hate color comparison tests.

Some people use the OTO to check for the presence of chlorine rather than any actual specific #, which may be useful, but I'd rather just spend the time using the FAS-DPD test. The DPD test can check for CCs and can read up to 10ppm FC if I remember right, but again, I hate color comparisons.

The FAS-DPD test has the highest scale and the .5 resolution on the test using the 10mL sample is more than good enough for government work.

All I've ever used is the FAS-DPD. I threw the OTO and DPD bottles away and use that spot in my case for the salt test reagents.