Testing free chloring with OTO

[DanielP]

I just opened my pool and tested with strips and it showed 0 CYA, so I added 4 pounds. About 2 hours later I took a water sample to Leslies. My counts were as follows:
FC 0
TC 0
PH 8
TA 180
CYA 0
CH 300
TDS 600
Phosphates 0

Since then, I've added 360oz 8% Great Value bleach from wal-mart and 7 - 83% tablets to tablet feeder in the evening and got a .5 FC reading at noon the next day. Then I added 2lb 65% Cal-Hypo and waited 2 hours and still tested .5 FC. However, if I wait a minute when testing it shows around 2 FC and if I wait 5 minutes it's >5 FC. It almost turns orange after 15 minutes.

How long should I wait for comparing the color? Does the OTO test drops go bad?

Why would Leslies tell me to add 2 gallons of muratic acid 1qt every 4 hours when the pool calculator says adding 2 gallons of acid would have dropped my PH from 8.0 to 6.6? Also, my PH on the comparator looks lower than when I went to Leslie's and looks around 7.6 on the comparator so I probably won't even need to use the acid because the CYA is dropping it. I told the guy I had just added CYA two hours before getting the sample, so I think he should have known my PH should go down.

 

[Isaac-1]

Ok, first off read the pool school link in the upper right a couple of times

Please don't take the rest of what I have to say wrong, we were all there at one point, but a lot of the rest of your questions show that you don't really understand the basics,

I will try to take the rest of your questions in order:

Test strips are notoriously bad at detecting CYA, most of the ranges that they show even if working right fall into moderate, to insanely high, and more than insanely high, so what use is there in a test that only tells you how much above allowable levels you are and has a big ballpark of inaccuracy. This is part of the reason so many of us around here strongly endorse the TF-100 test kit (see my signature), without a GOOD test kit it is impossible to correctly manage a pool.

Second part no surprise there, even if we do always question pool store tests, almost as much as we question their advice, CYA can take a week or more to show up on tests, it can also only be removed by water replacement, so give time to work and don't over shoot.

The tablets you added I assume are trichlor these will also add more stabilizer, so watch out and read above, they are also acidic

Ok on to the next point you refer to having some FC readings, how are you getting these as you go on to refer to the OTO test which does not read FC, it only reads TC?

first I am not sure about the shelf life of the OTO test, but most tests like it do have some limited shelf life and most importantly need to be stored in a cool place and not ever subjected to freezing. In general I think the OTO test kit is good for at least a couple of years though.

You are questioning pool store testing, and pool store advice, it is a great first step, now go back to the advice I gave you at the beginning of this message, read the pool school link in the upper right a couple of times (most people don't really catch that much the first time through), then feel free to come back ask questions, and we can help get you on track.

Ike

p.s. you should be very careful using cal-hypo and trichlor in the same pool as they can become explosive if mixed, also if the Leslies test is right your CH is already 300, which is a bit higher than you likely want, so you should avoid cal-hypo which boosts both FC and CH. (the only practical way to lower CH is through water replacement)

 

[DanielP]

Yes I understand strips suck but at the time it's all I had. I bought the OTO test yesterday but a lot of people haven't opened their pools so I'm not sure if I got last years test kits or not. Convincing my wife to buy a good kit is just not going to happen right now, maybe after I go all season asking she will relent. When I told her they only test for free to get you to buy their stuff, she pointed out that the pool lady here (not Leslie's) gave her a lot of free Crud last year and hasn't pushed anything on her. I really didn't have any way to continue making a point because I remember the free stuff.

I purchased 24lb of cal-hypo that I plan on using before switching to bleach, hopefully the CH won't spike too much. Had I used bleach in the past, I wouldn't have bought so much shock and possibly none at all. My current intention is to use tabs to get to and maintain CYA at 30-40 and mainly using bleach to maintain chlorine after I run out of shock.

When I get time I'll read the pool school again, I don't remember if it covered my other questions about the OTO testing in regards to waiting. I do remember reading in a post (I think on this forum) that some people thought the initial reading was FC and if you waited, you'd see the TC. I just don't know how long I should wait for a reading.

Thanks for the heads up on the incompatibility of triclor / cal-hypo, I have been pre-mixing the cal-hypo in a 5 gallon bucket and pouring it in front of the jet to disperse it which I feel is safe enough separation.

 

[kimkats]

I took my water to the 3 pool stores here in town. The water was the same water as in pulled at the same time and place.

Each pool store got wildly different results! It would cost me at the least $50 up to $150 to "fix" my water according to THEIR tests. BUT I knew from MY test results that my water was spot on!

You are going to have some HIGH CYA if you use all of your "shock" this summer. The only way to lower CYA is to drain/replace water. Depending on the cost of your water it might be a money saver to get the good test kit talked about here.

Good test kit = lower $ spent on pool stuff and less time spent ON pool instead of IN pool!

Good luck!

 

[JasonLion]

The OTO test shows the FC level for a couple of seconds, and then starts drifting towards the TC level color. If the CC level is high that drift can take a while, which is what you are seeing.

That means your FC level is very low, even though you added chlorine recently, and your CC level is very high. This tends to be a sign of ammonia in the water. Ammonia reacts with chlorine very quickly to produce CC. If you add enough chlorine you will eventually burn off all of the ammonia. How long that takes is rather variable, depending on what your ammonia level is. You can either keep adding chlorine until you can maintain an FC level, or find an ammonia test kit and get a sense of how much chlorine it is going to take.

Leslies is trying to get you to lower the TA level. Following their instructions will lower TA, but it will also bring the PH way too low and potentially damage the pool. I recommend lowering the PH to 7.2 any time it gets up to 7.8 (or higher). In the long run that will bring the TA down. I don't see any reason to rush to bring it down right now.

 

[Richard320]

Yeah, what they said.

You might want to look at your water bill and see what you're actually paying for the water. It might be cheaper to drain it than to eliminate the ammonia via bleach.

 

[Isaac-1]

If you can't splurge for the TF-100, can you maybe at least get the TF-50, it is smaller and will not last as long, but at least it will give you some good test numbers until it runs out.

 

[DanielP]

Post Posted: April 22nd, 2013, 5:56 am
I took my water to the 3 pool stores here in town. The water was the same water as in pulled at the same time and place.

Each pool store got wildly different results! It would cost me at the least $50 up to $150 to "fix" my water according to THEIR tests. BUT I knew from MY test results that my water was spot on!

You are going to have some HIGH CYA if you use all of your "shock" this summer. The only way to lower CYA is to drain/replace water. Depending on the cost of your water it might be a money saver to get the good test kit talked about here.

Good test kit = lower $ spent on pool stuff and less time spent ON pool instead of IN pool!

I have wanted a good kit for awhile, maybe I'll have my wife take a sample to the local pool store more often until she gives in.

The OTO test shows the FC level for a couple of seconds, and then starts drifting towards the TC level color. If the CC level is high that drift can take a while, which is what you are seeing.

That means your FC level is very low, even though you added chlorine recently, and your CC level is very high. This tends to be a sign of ammonia in the water. Ammonia reacts with chlorine very quickly to produce CC. If you add enough chlorine you will eventually burn off all of the ammonia. How long that takes is rather variable, depending on what your ammonia level is. You can either keep adding chlorine until you can maintain an FC level, or find an ammonia test kit and get a sense of how much chlorine it is going to take.

Leslies is trying to get you to lower the TA level. Following their instructions will lower TA, but it will also bring the PH way too low and potentially damage the pool. I recommend lowering the PH to 7.2 any time it gets up to 7.8 (or higher). In the long run that will bring the TA down. I don't see any reason to rush to bring it down right now.

Don't rush to bring TA, or don't rush to bring PH down since it is already getting lower from stabilizer? I just read this to get a better grasp on the subject and I was curious if aerating does anything else to the pool other than raise PH?

Yeah, what they said.

You might want to look at your water bill and see what you're actually paying for the water. It might be cheaper to drain it than to eliminate the ammonia via bleach.

I'm on rural water and it's expensive after a certain amount of gallons.

If you can't splurge for the TF-100, can you maybe at least get the TF-50, it is smaller and will not last as long, but at least it will give you some good test numbers until it runs out.

Again, I think the only way I'll get a kit is if I can make my wife tired of running samples to the pool store.

 

[kimkats]

LOL I like the idea of HER doing the running/testing for sure! "Honey if I had my own test kit I could do the testing here whenever I needed to."

 

[JasonLion]

There is probably no rush on lowering TA. The main reason to lower TA is so that the PH doesn't rise too quickly. If the PH is going up annoyingly quickly you will want to lower TA right away. Otherwise, keep the PH in range and TA will more or less take care of it's self.

Aerating raises the PH without affecting TA at all. Since all other methods of raising PH also raise the TA, this is one of the two steps in lowering TA (aerate and then add acid, the PH increase/decrease cancels out and the acid also lowers TA).

 

[DanielP]

There is probably no rush on lowering TA. The main reason to lower TA is so that the PH doesn't rise too quickly. If the PH is going up annoyingly quickly you will want to lower TA right away. Otherwise, keep the PH in range and TA will more or less take care of it's self.

Aerating raises the PH without affecting TA at all. Since all other methods of raising PH also raise the TA, this is one of the two steps in lowering TA (aerate and then add acid, the PH increase/decrease cancels out and the acid also lowers TA).

Good deal, we've had a lot of rain which is probably why the TA is high right now. I never had to lower PH in the past but did have to raise it last season.