Best way to use an OTO kit

[Rangeball]

I just received the kit I ordered from in the swim to tide me over until Ben's issues are resolved.

It's an OTO kit that measures FC, TC, PH, Alk and acid demand. I'll skip the last test.

Directions for PH and Alk are fairly straight forward. I'm wondering about the chlorine tests though.

Color chart reads 0-3 ppm. Should I just automatically dillute my pool water 1:1 with distilled water and multiply times 2 or even 1:2 then x 3? I run low stabilizer, and have been maintaining my residual between 2-4 based on test sticks and bleach calc #s.

I guess if I don't dillute and I get a 3 ppm reading, I should dillute and retest, and repeat for as long as I get a 3 ppm result?

The directions for FC and CC are interesting. Says to fill to line, add 5 drops of solution, shake to mix and match color within 2-3 seconds. To get CC, wait 1-2 minutes and check color again, subtract the difference.

Does this sound right?

The kit is produced by poolmaster. I've tried to get on their website, but it's not working at the moment (poolmaster.com).

[Rangeball]

Their site's working now.

Here's the kit-

[prh129]

I beleive that waterbear has said that OTO method for FC/CC really doesn't work and it makes sense because the CC is usually pretty low (0.5 to 1ppm when high) so it is unlikely that you will be able to get that level of detail out of the color comparison test.

I think the FAS-DPD test is the only way to get accurate CC. You can buy that test separately on the poolsolutions site.

Peter

[Rangeball]

Thanks. I'm just trying to bide my time until I can get Ben's main kit.

I ran the tests at lunch and the potential limitations of the OTO kit quickly showed themselves.

But at this point it's better than nothing. I'm pretty certain I don't have CC, as I've been holding a residual tested with FC test sticks that matches the results of the OTO. They could all be fubar, but the pool is squeaky clean (vinyl liner) and crystal clear

[prh129]

I bought a similar kit to hold me over until Ben's kit arrived at it worked just fine.

As far as diluting your sample, the more you dilute, the less accurate it gets so if you are within the range of the tester, I wouldn't dilute it. If you're staying around 3 ppm with a CYA level of 30 or under you should be fine.

Peter

[waterbear]

OTO only tests TC. It will not give you any kind of accurate reading for your FC, actually some of the test strips might do a better job at this than trying to get a FC reading with OTO (and I do NOT recommend test strips!)

[Rangeball]

OTO only tests TC. It will not give you any kind of accurate reading for your FC

I emailed the kit manufacturer asking if their kit did in fact test for FC and TC, as they claimed, and if they were separate tests. Got this response-

It is not a separate test.

For a free chlorine reading, within 2-3 seconds after putting in the oto drops, compare the color in tube.

For a combined chlorine reading, wait 1-2 minutes after putting in the oto drops and again compare the color in the tube.

True or false?

My color never changes no matter how long I read it. Going by this, I have no CC.

[mas985]

I have used this method before on my spa. I believe that the second part after 1-2 minutes is really measuring TC and not CC. To get CC then you must CC = TC - FC. With a high CC, you will notice the solution getting darker over time. However, you generally cannot measure a CC of < 1 ppm since it is difficult to tell the difference in color. Even at high levels you do not get a very accurate reading. But then again all that you really want to know is that your CC level is bad and your pool needs a shock.

[jrv331]

I was using the Poolmaster Kit for the past two years before finding this forum. Thought it was great UNTIL I got a Taylor kit that had the red vial markings. Being new I tried the FC/TC tests with both kits(being anal)several times - each time it was hard to read with the yellow Poolmaster vial but easy with teh red Taylor vial. Short answer to your question - the Poolnmaster never gave a FC reading despite their instructions.

JOhn

[waterbear]

I emailed the kit manufacturer asking if their kit did in fact test for FC and TC, as they claimed, and if they were separate tests. Got this response-



True or false?

My color never changes no matter how long I read it. Going by this, I have no CC.

This will only work if you have a LOT of CC in the water. It is really not useful at all. If you have enough CC to show with this method of OTO testing you will already know it by the strong chlorine smell and the burning eyes. I stand by my statement that OTO only tests TC! You cannot accurately get a FC reading with it. This is why most health departments ( or is it all now?) only allow DPD or FAS-DPD testing of commercial pools.