Chlorine tests to 0.2FC and book

[investindy]

Doing an experiment and need to get a little more precise then 0.5 increments for my FC levels.....I thought if I read the Taylor stuff correctly they have either a drop equals 0.2 out of one reagent and the other one does 0.5 per drop...Thus, you could get more resolution with the 0.2 or even mix/match and count/multiply for your results....Does the TF kit have both the 0.2 and 0.5 capability?

Also does your kit have the watergram or some form of the water chemistry booklets information??? I think I can get the SI from Jason's pool calculator so I guess I don't need the wheel, but what about the guide?? I have never seen one so I don't know what contents are in there.

 

[JohnT]

The 0.2ppm per drop test is just a larger sample size to make each drop a smaller portion of the sample. You can test either way you want just by filling the sample bottle to the appropriate line and using the appropriate multiplier per drop.

 

[chem geek]

Specifically, a 10 ml sample size for the chlorine test gives you 0.5 ppm per drop while a 25 ml sample size gives you 0.2 ppm per drop.

 

[Guest]

The book that comes with the Taylor kit is not that great. It does contain some misinformation and the majority of it is just treatment tables. Jason's calculator is a much easier way to do the same. You have MUCH more info about pools available to you in the Pool School section of the forum.

However, I have been following some of your posts and I want to remind you that we are dealing with swimming pools, not science experiments, and also about the limitations of testing accuracy. Some people get into a tendency of micromanaging their pools.

 

[investindy]

Waterbear thank you for your honesty....Just trying to get various pieces of the puzzle together to setup a chlorine dispenser....I will post the equipment/process to share knowledge back from what I learn from my experiment...Yes I'm trying to dial in things as an experiment because I want to understand where to set my thresholds for when and how much bleach to dispense my 21,000 gallon pool....I appreciate everyones time to respond. I hope that my posts will help others as well that may of considered going down the path I am. I am a controls engineer by trade so I understand automation but water chemistry is a rather new field for me. My experience thus far is just in PH, Coagulation, and Flocculation processes dealing with water. I am all questioned out till I get some data from my testing and hopefully if I run into something the forum can still help me and whomever may need similar information. THANK YOU EVERYONE, AGAIN I WILL SHARE BACK WHAT DOES/DOESN"T WORK and how I built it so cheaply from parts off Ebay!!!

 

[Guest]

I assume you are using an ORP controlled peristaltic pump. This is well documented since is it very commonly employed in commercial installations and I would start by reading the literature available (and much of it online and also contradictory!) from the various manufacturers of ORP controllers and associated equipment. There is also the rather interesting (and fraught with inaccuracies) "Swimming Pool Control with Linux"
http://www.truetex.com/poolcontrol.htm
which gives a detailed explanation of how one man did it. However, his understanding of water chemistry is a bit lacking at times. Good luck with your 'experiment' and keep us posted!

 

[investindy]

Yes you nailed it, using a peristaltic pump that goes to a very low flow ( I could run it the entire day on low to just meet my needs). Would work perfect for those wanting to have something auto put in chlorine while on vacation etc)...Trying to dial it in a little more....In Phase two I have a ORP sensor and controller (already have it) I will use to dictate when to turn on, delay the time to read again and if I'm not over the minimum threshold dose again, continue cycle till ORP reading is happy and a built in time-out if not at the right level after a few attempts should something go wrong (dont want to put in 10 gallons or something crazy at once)....I will read the link, did not know it existed!! :viking:

Edit: Just skimmed the article, yeah that guy is a little far out....Keeping mine simple per the above, I am using a PLC though to handle the time of day for my circulation pump, time for the chorine dispense, counting batches, reading just a discrete input for the level to add chlorine (from ORP controller), etc...No computer, or fancy $900 switch, OMG...I have bought the ENTIRE system I need (mostly used parts) for less than $250, this includes the contactor to pull in my hayward pump and the PLC brains!!!!

USING BBB techniques and having basic hardware to know when to add, control it, and when to stop is really all there is, KISS (Keeep It Simple )...Sunlight changes, additional needs, etc will be taken care of by just estimating 1/2 my daily needs let it dose, then on low days it may do one round of chlorine, on high need days it may dose three times to get to my needed ORP levels. Doses over 4 and ORP still doesnt see a high enough level shut it down for safety... Hopefully if that happens I'm just out of Clorox.

 

[Guest]

Instead of messing with ORP and pH electrodes why not just test the chlorine and pH daily and adjust the pumps for chlorine and acid (if you are also using an acid pump) until your water is stable. Should only really take a week or two to do so and then you are good for the season. You still need to test your water weekly whether you are using ORP or not for FC, CC, pH, TA. Test CH and CYA monthly unless you suspect there is a problem or you have added or removed a bunch of water for some reason. KISS!!! This is the technique used by many commercial installations (and some residential ones) that use automatic feeders but do no use control automation. IMHO, it is much simpler to set up and has far less problems in the long run! One rule I can give you about automation systems--they WILL screw up when you least expect it!

 

[H2O_Keeper]

Can I choose if I want the drop qty for 0.2 or 0.5 accuracy with the TF100? Thread discusses how its the same reagent different sample size. I know the Taylor kit has the line for the option for sample size, what about the TF100?

BTW what is an ORP test?

 

[chem geek]

The TF100 uses a graduated sample tube similar to the one shown here from Taylor (or here in the TF100 kit). It has lines every 1 ml starting at 5 ml and a major line with a number every 5 ml up to 40 ml so you can easily use either a 10 ml sample size for 0.5 ppm per drop resolution or a 25 ml sample size for 0.2 ppm per drop resolution.

ORP isn't a test using reagents. It stands for Oxidation-Reduction Potential and is a type of measuring device that measures a voltage that roughly relates to the amount and strength of oxidizer in the pool. It approximates the amount of "active" chlorine (hypochlorous acid) in the pool, but is more susceptible to pH, temperature and other factors (such as hydrogen gas from SWG systems). The second graph in this post shows this relationship. If your pH, temperature, and CYA level are fairly stable, then you can use an ORP device in a control system for maintaining the Free Chlorine (FC) level, though it can have problems as waterbear pointed out.

Richard