LaMotte ColorQ Water Tester

[donaldm823]

has the CYA and hardness tests been resolved with this unit? I like the idea of this thing, but the main draw for me is the CH and CYA tests, and if they don't work, its a bit of a waste.

also, are the liquids or tablets better? The tablet version seems more expensive to refill.

I have been using the LaMotte ColorQ since May07 (I closed the pool in Oct07). I believe my earlier problems with CYA were self induced. In the end, I mix the CYA pill vigorously in the test tube after crushing and waited 3-4min and got consistent results with other methods (Taylor black dot). Also your pool water temp must be 80F.

As for CH-I was convinced that ColorQ was reading low as it gave me a 190ppm reading when the Taylor titrant gave a 300ppm. In mid Aug I installed a SWG. At the end of the pool season I had no calcium deposits on the SWG cell indicating I was running CH at the low end. (with 300ppm, you should get white deposits on the electrolytic cell plates per Autopilot. So bottom line-I believe now the ColorQ was giving me a good CH hardness reading and the Taylor titrant was way high due to other interfering items in my water

I plan to stick with the ColorQ-so I endorse the system and its is better than LaMotte's PC-4 system (works on same principle but only tests for chlorine and pH). Also using the liquid reagent drops is way better than the hard pills that you crush, both from a cost as well as ease of use and mixing. You can get the liquid refills direct from LaMotte via phone order.

 

[chem geek]

I'm glad the LaMotte ColorQ is working so well for you. As for the problems with the Calcium Hardness (CH) test with the Taylor test kit, Taylor says the following about interference in this test:

Metal ions may cause interference; to prevent, add titrant containing EDTA to sample before buffer and indicator, then test as normal making sure to count drops of titrant added initially in total required to reach endpoint. If interference still occurs, dilute sample with DI water as necessary and retest.

I'm concerned that in your situation it seems there was no way to work around the interference in the Taylor test. I know in my pool it's reasonably accurate because I get expected cloudiness if I add pH Up (Sodium Carbonate) that eventually dissipates and can form calcium carbonate chunks if it's dumped in quickly and these dissolve very slowly (I've also taken a water sample and raised the pH enough to cloud and scale).

Also, I seem to recall waterbear's instructions that one must thoroughly mix after each drop of the CH test -- something like 30 seconds after each drop to ensure accurate testing. I just wonder if there is any way to get the Taylor test to be accurate with your water. It's not a problem for you as you have a now-determined-to-be accurate tester, but for others using the Taylor test it would be good to know if it can be used reliably.

Richard

 

[Guest]

We use the LaMotte Waterlink Express at work and we have problems with it giving much lower CH readings than the Taylor titration test, usually on the order of 100 ppm low when the CH is above about 400 ppm, unless calcium is very high (above 500 ppm) , then the Lamotte colorimeter would read about 480 ppm. This is the effective upper range of the unit (500 ppm). The colorQ has an upper range of 400 ppm if I am not mistaken. I have spoken to tech support at LaMotte several times about this and they have admitted that there are some problems with their colormetric calcium hardness test. They told me that if calcium levels are near the upper end of the units range it will read low and that I should use a titration test since it would be more accurate under those conditions. Since the Waterlink Express has a greater range than the colorQ this does not occur until until calcium levels are above about 350-400 ppm. Also the resolution of their calcium hardness test is +10/- 25 ppm while the Taylor is +/- is 10 ppm. This means the LaMotte test is more likely to read low than the Taylor. Their advice was to use the titration test when high calcium levels are suspected since it would be more accurate. This does not make the ColorQ a bad unit by any means but knowing it's shortcomings can help you make better use of it!

In your case you are reading about 100 ppm low and your calcium levels are within 100 ppm of the upper range of the unit so it seems that the colorQ has the same problem as the waterlink express.

As far as having a CH of 300 ppm with a SWG, this does NOT mean that you will have scaling on your cell. I run my calcium at about 250-300 ppm and have NEVER had any calcium deposits in two years of use! A lot depends on how well you are at keeping the pH in line since high pH is what is going to cause scaling conditions more than any other factor with temperature being the second most important parameter (the higher the temperature the more likely scaling is to occur, also if you are running your TA on the low side it will lower the saturation index too but this is a very small factor in predicting scaling conditions).

IMHO, the best advice would be to use the colorQ but titrate your calcium test with the Taylor kit. This is basically what we do in the store. We also titrate the TA test if chlorine levels are high since it is prone to bleach out when chlorine levels are above about 6 ppm. This is a factor with the dry reagents used in the Waterlink express and I do not believe it affects the liquid reagents used in the colorQ.

 

[donaldm823]

I'm glad the LaMotte ColorQ is working so well for you. As for the problems with the Calcium Hardness (CH) test with the Taylor test kit, Taylor says the following about interference in this test:

Metal ions may cause interference; to prevent, add titrant containing EDTA to sample before buffer and indicator, then test as normal making sure to count drops of titrant added initially in total required to reach endpoint. If interference still occurs, dilute sample with DI water as necessary and retest.

I'm concerned that in your situation it seems there was no way to work around the interference in the Taylor test. I know in my pool it's reasonably accurate because I get expected cloudiness if I add pH Up (Sodium Carbonate) that eventually dissipates and can form calcium carbonate chunks if it's dumped in quickly and these dissolve very slowly (I've also taken a water sample and raised the pH enough to cloud and scale).

Also, I seem to recall waterbear's instructions that one must thoroughly mix after each drop of the CH test -- something like 30 seconds after each drop to ensure accurate testing. I just wonder if there is any way to get the Taylor test to be accurate with your water. It's not a problem for you as you have a now-determined-to-be accurate tester, but for others using the Taylor test it would be good to know if it can be used reliably.

Richard

Ok-thanks to chemgeek and waterbear-another lesson in pool chem!!! I admit, I have never waited 30 sec after each hardness reagent drop, as that would be 25d x 30sec or 12 minutes!!! I do add 5 drops of the CH3 solution first and that helped somewhat. I never heard of the ColorQ upper range CH reading low. So when I open the pool, I guess I will search for a pool store that uses waterlink express and validate which CH is correct (ColorQ or Taylor).

If I buy a magnetic stirrer, would that eliminate the 30 sec wait?. I probably have only waited 3-4 sec after a group of drops, as I often add 4-5 drops at a time before I get within the expected range of my hardness. It looks like I was doing the Taylor wrong and I know I have some metal ions in the water (Nature 2)( I removed the Nature 2 when I installed the SWG).

Either way, I still love the ColorQ as the CH result did provide trending.

But, now I am back to square one as to what is the REAL hardness for my pool!! LaMotte did send me a 250ppm hardness standard, and my Taylor measured 300ppm using my old drop method method-so I have assumed the Taylor was reading at least 50ppm high. In that test my ColorQ read 230ppm (20ppm low). I am hoping my hardness will be lower next spring due to dilution, since I lowered the pool level for the winter-hopefully the dilution will eliminate the high hardness issue that waterbear is talking about. I definitely will not be adding any CaCl based on the ColorQ result until I validate.

 

[Guest]

Ok-thanks to chemgeek and waterbear-another lesson in pool chem!!! I admit, I have never waited 30 sec after each hardness reagent drop, as that would be 25d x 30sec or 12 minutes!!!

Yes, that is correct. Allow about 20-30 seconds of swirling between drops or use a magnetic stirrer if you want to do the test faster!

I do add 5 drops of the CH3 solution first and that helped somewhat. I never heard of the ColorQ upper range CH reading low.

The ranges of the tests on the ColorQ are right on the LaMotte website. They list the resoluton but not the accuracy of the test. I have spoken with tech support and they told me the CH test has an accuracy of +/- 25 ppm and the waterlink express is +10/-25 ppm.

So when I open the pool, I guess I will search for a pool store that uses waterlink express and validate which CH is correct (ColorQ or Taylor).

I can tell you right now the Taylor test is going to be more accurate at high calcium levels since it is a titration test and NOT a colormetric test.

If I buy a magnetic stirrer, would that eliminate the 30 sec wait?.

Yes, it will speed up the test considerably! Not waiting between drops won't really change the results of the test by much but helps to eliminate a 'floating endpoint" (an indistinct purple color instead of blue) and also helps eliminate the particles that can form and mask the endpoint.

I probably have only waited 3-4 sec after a group of drops, as I often add 4-5 drops at a time before I get within the expected range of my hardness. It looks like I was doing the Taylor wrong and I know I have some metal ions in the water (Nature 2)( I removed the Nature 2 when I installed the SWG).

The LaMotte test can also read wrong if metals are present. It is the nature of a chelation test. The problem with the colorQ is that it depends on a specific color change that the meter reads (colormetric test, same as comparing the results to a color chart manually--just more accurate than the human eye) so by nature a titration test such as Taylor's is going to be more accurate and have a greater range (a meter colormetric test is going to be limited by the range the meter can read). The amount of metals added by the N2 is small in most cases and should not have any major effect of the results of either test.Either way, I still love the ColorQ as the CH result did provide trending.

But, now I am back to square one as to what is the REAL hardness for my pool!! LaMotte did send me a 250ppm hardness standard, and my Taylor measured 300ppm using my old drop method method-so I have assumed the Taylor was reading at least 50ppm high. In that test my ColorQ read 230ppm (20ppm low). I am hoping my hardness will be lower next spring due to dilution, since I lowered the pool level for the winter-hopefully the dilution will eliminate the high hardness issue that waterbear is talking about. I definitely will not be adding any CaCl based on the ColorQ result until I validate.

You might also want to get a standard from Taylor, they have them also. I CAN tell you that LaMotte has had quality control problem with their reagents for the Waterlink Express (TA test--they have replaced reagents for us more than once) so I have lost a bit of faith in them.

 

[Sabot]

Very interesting info, thanks gents!

A few questions:

- if I understand correctly, I need to wait 30 seconds after adding the reagents before having my ColorQ take the reading?
- should I shake, stir or some other method when mixing the reagent prior to reading?
- does air bubble impact the reading?
- can I use other supplier's reagents with the ColorQ or do I need to order from LaMotte only?

Thanks in advance!

 

[Guest]

Very interesting info, thanks gents!

A few questions:

- if I understand correctly, I need to wait 30 seconds after adding the reagents before having my ColorQ take the reading?

No, that is the Taylor CH titration. the tube needs to be swirled for 20-30 seconds between drops or a magnetic stirrer can be used for quicker mixing. With the ColorQ most tests should be read immediately, particularly the FC.

- should I shake, stir or some other method when mixing the reagent prior to reading?

Depends on whether you are using liquid or tablet reagents. Tablets are crushed and then the tube inverted a few times, depending on which test. The CYA test does need to sit for at least 2 minutes before reading. The instruction manual gives the number of times needed to invert the tube for each test and the waiting time, if any.
For the liquid reagents, since they mix quickly, just inverting the tube a few times will mix it well. Check the intruction manual for details on each test.

- does air bubble impact the reading?

Yes!!! If there are any bubble in the tube you should gently tap the bottom of the tube on a flat surfave to dislodge them. If you invert the tube a few times to mix instead of shaking it you will be less likely to have bubbles in the tube.

- can I use other supplier's reagents with the ColorQ or do I need to order from LaMotte only?

I woud not suggest it since the meter is designed to read LaMotte reagents made for this test. Other company's reagents would not give you accurate results.

Thanks in advance!

Hope this helps.

 

[Sabot]

Quick update... I have been using the tester on both my Spa and my Pool since Oct 2007. I also verify my readings against the TF100 to ensure I am getting good readings. So far...so good. Testing only takes a few minutes and I have been keeping a log since the start. What I don't like is the pool store readings can be way off the readings of 'Q & TF100. (I like to take a sample to two differant stores to get my readings. Funny how the stores have differant readings...)

I have only used 3 tablets in the feeder (put there by the pool installer) then I switch when they ran out to BBB. Everytime someone comes over, they ask if I have salt water since the water looks so clear. Just the other day, my wife stated it look so nice that I must becoming a chem geek. Nah.. Just keeping up on taking readings and using only BBB. The Liquidator has taken the hassel out of adding bleach. My wife call's it the expensive trash can. Using skimmer socks has reduced my backwashing down to almost nothing. Since the pool started, I had to flush once so far.

 

[Sabot]

A quick update...

I have been seeing huge off sets between the TF100 FC test and the ColorQ tester. I am assuming that the meter can't handle FC over 4. I noticed when the FC is less than 4ppm, the difference between the TF100 and the ColorQ are small.

Example:

TF100:
FC: 4.5
TC: 4.5
CC: .0

ColorQ Pro:
FC: 8.52
TC: 9.42
CC: .9

I have always notice a difference between the ColorQ and my Oakton pH meter. I don't know which one to believe, so i normally split the difference. I am calibrating the Oakton before each test. I would assume that the Oakton is more accurate. Am I assuming correctly?

Oakton pH Meter:
PH: 7.12

ColorQ:
PH: 7.5

I have emailed the factory a number of times with not a single response. I think my use of the ColorQ is drawing to an end once I use up the testing agents.

I think I am going to stick with the TF100 and the Oakton meter. Thoughts?

 

[Guest]

We use LaMotte meters at work and I back it up with Taylor testing. Make your own judgement as to why. LaMotte's tech support and qualitly control is not what it was, IMHO.

 

[Sabot]

Waterbear,

Am I making the right choice on dumping the ColorQ and going with the TF100 & Oakton pH for my testing?

The ColorQ numbers are not in line with the TFF or the Oakton. I have been using the ColorQ daily since I bought it. I am wondering if it needs to go back to get recal?

 

[Guest]

Try calling LaMotte if they are not answering emails. I have never had a problem with email to them but we are a LaMotte retailer so they probably want to keep in our good graces.

 

[duraleigh]

As a reseller, I thought the ColorQ might be a good compliment to offer as an alternative to a drops based kit.

After considering it for several months, I felt like it simply was not accurate enough to do what most folks on this forum expect it to do. I would still l like to sell it but mostly because of posts like this, I don't intend to until their accuracy and repeatability approaches the drops-based kits.

 

[Sabot]

Dave,

Do you believe your tests are more accurate then ColorQ?

 

[duraleigh]

By far. Not just mine, but drops based tests in general seem to offer far more accuracy and consistency than the ColorQ. Waterbear is a far better judge of that than me but I'm pretty sure he has similar feelings.....esp. reading his post above.

 

[Guest]

Keep in mind that this is a $100 colorimiter (once you figure out the price of the reagents)! While it does a decent job it is no where near the accuracy or precision of more costly units. The LaMotte colormeter I use at work has a retail of over $1000 and even it has some problems.

IMHO, the colorQ is a definite step up from test strips but it is not in the same league as drop based kits (which LaMotte ALSO makes, usually aimed at the commercial and pool maintenance market and for the 'advanced' residential pool owner!) They even have a stand alone FAS-DPD test kit!

All in all their drop based kits are very much like the Taylor ones with many of their kits using slide comparators like the more expensive Taylor kits and they use direct reading back titrations in some of there kits instead of drop count titrations (just a dfferent method, not any better or worse). The colorQ is a great gimmick to increase sales but it's not a serious testing method but more of a high tech toy, IMHO.

Realize that even Taylor makes test strips! (Dave, have you considered carrying them? Just joking, Dave! ) The Taylor test strips are actually one of the better ones that I have used but it is still a test strip with all their inherent problems. Taylor is just tapping into that market. These companies are businesses, after all.

We know what works when it comes to water testing and we know what doesn't. Does any more really need to be said?

 

[deenamccauley]

I've used the Color Q for about a year now and have found that it is now consistantly different than my Taylor test.
I had issues with the CH from the begining and they sent me their new, corrected reagaents but I still had inconsistant results. Their answer to the CYA being way off was for me to use another testing method. Kind of defeats the purpose of spending that kind of money on a test if you can only use it for chlorine and PH.
They then sent me an updated meter which seemed to correct the problem at least with Ph and chlorine readings but the CYA and CH were still not right. Alk was close but still not close enough to be called the same or tester error.
As time has gone by I find the Chlorine readings are almost always 2 points higher than my Taylor test. And just going on my health unit testing from last year and this year I'd say the Taylor is correct. I had bacteria issues last year when I treated according to the Color Q. So when I was reading that my Chlorine was 3, in reality is was probably only about 1.
I hardly use my Color Q anymore because I just do not find it accurate enough for what I need. I sure wouldn't recoomend it to anyone.

 

[Sabot]

I just bought a supply of agents for my ColorQ too! Doh...

Anyone want them before I sell them on eBay?

 

[Jimbo]

After reading all this, I'm sure glad that I made the correct choice on Father's Day. My wife said I could have the Color Q or the TF-100. I came close to getting the Color Q. I just didn't find enough good comments here like you do about the TF-100.

 

[stevet1]

When my pool was built last year, I also had so many questions about getting accurate pool testing readings. I was very unsure if I could tell the difference between small shades of yellow, pink, orange, etc.... so, despite reading all the good advice here, I went and got myself many hundreds of dollar in test kits:

TF-100
ColorQ
Extech EX900 (http://www.extech.com/instrument/produc ... ab_CL.html)
And of course a smattering of test strips, etc...

I got a bunch of buffer solution, and I use the extech for more of a reference testing for Free chlorine and pH. I was initially interested in ORP as well since I have an Autopilot TC system, but like Jason, I couldn't get ORP to work reliably, it's much easier to just set a % output on your SWG.

pH - was by far the hardest for me to get an accurate handle on. The Extech made it easy, but unless you have tons of buffer solution and time in order to calibrate, it's not practical for an everyday pool owner to use. The Color-Q was fairly reliable in testing pH, but it always read +0.1 to 0.2 higher than the actual pH. After several hundred tests now, I think I've got the basic phenol red test down to the point where I can discriminate slight changes in pH.

FC- It's very difficult for me to differentiate between various shades of yellow or pink. The FAS-DPD in the TF-100 is extremely accurate and reliable for testing FC. It correlates extremely well with my direct chlorine meter. Be sure that you use fresh reagents though. I noticed that my first set of reagents (stored improperly my fault) from last summer were no longer accurate. The Color-Q unfortunately is fairly useless in this regards for me. I want to keep my FC above 4 and more towards the 5 range. In this range, my colorQ always reads too high to measure.

ALK- ColorQ completely useless. It gives me very variable test results, and all of them are 30-40 points below my drop based test. Drop based test have always been very reliable for me. I must say that the dropper tip on my TF-100 gives drops that are slightly too big, I always read 10 points lower (1 drop less) compared to using the original taylor bottles/tips.

CH- ColorQ isn't too bad in this respect. I've had readings +/- 50 compared the the drop test. However, the drop test is so much more reliable (you get the same result each time). just watch the age of your reagents and make sure they are stored properly.

CYA - ColorQ is hard to assess. I always get a reading about 25-30 points lower than actual. Even following all the precautions - warming up the sample, mixing thoroughly, giving it time to dissolve, etc... ColorQ always gives a much lower reading than actual. I don't particularly like the turbidometric test with the disappearing dot either, but it seems to be more in the ballpark than the colorq.

In short, my ColorQ is basically only good for pH, and really only after I've used a very accurate pH meter to determine the difference between the ColorQ reading and the actual pH. It's ok for CH (at least in the ballpark), but overall probably not worth it.

The TF-100 is has been overall much more reliable and accurate. Just make sure you have fresh reagents. I still wish there was an easier way to discriminate small changes in pH (without a good pH meter and lots of reference buffer solution) there just isn't. Keep practicing with the phenol red drops. I have to hold it up to a blue sky in order to detect small differences. If I use a white background or even a cloudy day, I have trouble with the comparator. Luckily, once my Autopilot TC pH meter was properly calibrated, it's been providing me accurate and reliable readings, and I haven't had to recalibrate for at least the last 4 months.

And if anyone knows of a better and more reliable way to test CYA, let me know.