Reburn Posted November 2, 2014 Share Posted November 2, 2014 This will be a multi post topic. I am posting as I do the experiment. So the thought for this experiment started on day while I was at SAMs house picking up some SPS pieces. Now with that being said Sam has a gorgeous tank with all the desirable and beautiful SPS pieces and I should probably go over there less because I always go for 1 piece but like lays.....Lol well. Self control is a whole nother post. So we go into a conversation about phosphates and our current testing. Most of us that are heavy into SPS and others are using Hanna colormeters. The lime green ultra low phosphate version that is HI 713. They take the reagent packets Hi713-25. I have been having heck getting my phosphates up. My nitrates hover about 10ppm but it's routine that my phosphates read 0, I have been at 0 for almost 3 months now. So as some know like Ty, 0 phosphates will cause your SPS to loose color and sometimes even stn due to ultra low nutrients. It hasn't been great for my zoas either. So Sam asked me how are you testing. So I walked through my testing which includes using both cuvettes and washing them as outlined by victoly in our lab procedures post found here (http://www.austinreefclub.com/topic/31692-lab-procedures/ ). I use both cuvettes because sometimes I see the need for the particulates in the water to settle so I can get an accurate reading. I also sometimes space and forget about the 2 minute limit. So for this experiment I am using both cuvettes. So Sam tells me that I am doing everything right but he was having problems and his friend wizard (Tim) told him that he needed to be using another reagent that has better sensitivity. Now with that being said, Hanna says your supposed to use the Hi713-25 packets (I will be referring to these packets as the green packets). Sam tells me to use theses packets and hand me a stack. Well they are Hi93713-0 which is a phosphate low range reagent (I will be referring to these packets as blue packets) Huh well I give them a try. So a week went by and I finally got around to using them. I was astounded. My green packets as usual read 0 but the Blue packets read 0.16ppm. So obviously I'm scratching my head. That doesn't make sense to me. I called my friend esacjack (Gary) and we discussed it and come to the conclusion that something can't be right. I had the same conversation with Ty as well. So we hatch this experiment for me to do to test and see which packet is more accurate. After I'm done if the results are still different I will be emailing this thread to Hanna as well to see if they have any input. 1 Quote Link to comment Share on other sites More sharing options...
Reburn Posted November 2, 2014 Author Share Posted November 2, 2014 Step 1: Control I am using a purchased bottle gallon of distilled water, dumped out and refilled with 1 week old salt mix that has been agitating all day.. I am using Red Sea salt mixed into a 55 gallon barrel on RODI that is coming through a BRS 5 stage chloramines unit, 75 gallons a day with dual DI resin and a built in TDS meter. I routinely test my nitrates in my RODI and fresh salt mix with a Red Sea Pro nitrate titration test that measures in fractions of ppm to ensure my water is clean. The same C1 vial was used both times for both packets. The water in C1 wasn't changed in between reagents and the cuvette glass wasn't touched. The first test on the clean salt water with the green packet, each test was run through the meter 5 times and it came up 0 all times. The first test on clean water using the blue packet, each test was run through the meter 5 times and it came up 0 all times. Quote Link to comment Share on other sites More sharing options...
Reburn Posted November 2, 2014 Author Share Posted November 2, 2014 Step 2: adding phosphates For this step I am using sea chem phosphorus to elevate the phosphate levels. The formula is 0.8vp=M Where V is the volume of water in gallons and P is the desired level and M equals the dose in milliliters. I want to dose to 0.25ppm since the accuracy on the Hanna is 0.04 plus or minus. So; 0.8x1x0.25=0.2ml I am using a TB syringe with a 18ga 3/4" needle which is the proper name for the syringe with the little lines that the salifert tests come with. The needle and hub have been tested to hold .08 ml when the liquid reaches the 0 mark. So I pulled some air and then pulled the chemical to .12ml and injected into the water and shook and let set for 5 minutes. Quote Link to comment Share on other sites More sharing options...
Reburn Posted November 2, 2014 Author Share Posted November 2, 2014 The results for the green packet was as expected. Average 0.27ppm out of 5 tests. The vials were allowed to sit for 5 minutes after mixing the reagent to ensure any particulates had settled and any micro bubbles floated. Quote Link to comment Share on other sites More sharing options...
Reburn Posted November 2, 2014 Author Share Posted November 2, 2014 The results for the blue packet was a little interesting. Average 0.38ppm out of 5 tests. The vials were allowed to sit for 5 minutes after mixing the reagent to ensure any particulates had settled and any micro bubbles floated. Quote Link to comment Share on other sites More sharing options...
victoly Posted November 2, 2014 Share Posted November 2, 2014 OK so i don't want to break your experiment, but 2 vials is going to introduce error, for sure. I started getting better reproduce-ability when i quit doing two vials. The time is a huge shortcoming in the phosphate meters, because you're right, sometimes it takes 2-3 minutes to get the reagent to dissolve. So my method is to make sure my packet is pre-opened and ready to dump into the cuvettte; fill the cuvette with sample, do c1; remove cuvette and add reagent (keep in mind you have 1.5 minutes before the meter shuts off); so i turn the tube for 1 minute and THEN press/hold so that the three minute timer starts. I can usually get my sample fully dissolved in that time period with 30 seconds or so to wipe the vial and remove bubbles. I'm pretty sure the blue and green reagents are literally the same reagent, just with different lot sizes. One would like to think that they should be the same, but in practice they can vary some from lot to lot. Quote Link to comment Share on other sites More sharing options...
Reburn Posted November 2, 2014 Author Share Posted November 2, 2014 Final notes: Some of the first post were edited after the last post. I remembered something that I wanted to add or just spelling and grammar. I will not edit any of the first posts after this post. The blue reagent packets are not a powder like the green packets. The grains are coarser and they take more then 2 minutes to dissolve. You must use 2 curvettes when using these reagent packets. The C1 cuvette remained constant from the green packet and blue packet experiments. The cuvette glass wasn't touched in any way. However it is my habit as I'm testing multiple times on the same test to rotate the vials slightly as I put them into the meter. I believe that this will eliminate any discrepancies from any micro scratches in the cuvettes. I as well routinely pull the average for a minimum of five tests on the same reagent mix. It's intresting that the blue packets read 0.11 higher then the green packets. While in sure that there could have been a hundredth of the seachem phosphorus slip by me there is no way that 0.08 or almost a tenth of a ml slipped by. The blue packets are also quite a bit cheaper running about $26 for 100 reagents!! Hanna list the packets as a phosphate low range ascorbic acid method for a photometer reagent. The green packets are running about $10 for 25 reagents at bulk reef supply and Hanna list them as phosphate low range ascorbic acid method for checker HC. At the end of the day I'm not quite sure what to think in the end. I believe I'm going to continue to use the green packets but at the end of the day I think that the 0.04 range of accuracy is a problem for reefs in general as your phosphate can be reading 0 but actually be 0.04. The only benefit that I can see is if you are trying to run a true ULNS or Zeovit system the false high reading would be a good indicator that your phosphates may be at detectable levels. In the end I'm still less then thrilled about current phosphate testing and I don't see that changing anytime soon. Quote Link to comment Share on other sites More sharing options...
Reburn Posted November 2, 2014 Author Share Posted November 2, 2014 OK so i don't want to break your experiment, but 2 vials is going to introduce error, for sure. I started getting better reproduce-ability when i quit doing two vials. The time is a huge shortcoming in the phosphate meters, because you're right, sometimes it takes 2-3 minutes to get the reagent to dissolve. So my method is to make sure my packet is pre-opened and ready to dump into the cuvettte; fill the cuvette with sample, do c1; remove cuvette and add reagent (keep in mind you have 1.5 minutes before the meter shuts off); so i turn the tube for 1 minute and THEN press/hold so that the three minute timer starts. I can usually get my sample fully dissolved in that time period with 30 seconds or so to wipe the vial and remove bubbles. I'm pretty sure the blue and green reagents are literally the same reagent, just with different lot sizes. One would like to think that they should be the same, but in practice they can vary some from lot to lot. Yes I agree that using the C1 C2 method can introduce a variable with micro scratches and thickness of glass cuvettes. However it is impossible to dissolve the blue packet completely in 2 minutes. So for consistency through out the experiment I chose to use the C1 C2 method and try to limit the variables such as changing the water or touching the cuvette C1. As I said in the previous post the blue packet acid grains are a much coarser grind and there appears to be more. But that could just be an optical illusion due to the coarser grinds. Quote Link to comment Share on other sites More sharing options...
Reburn Posted November 2, 2014 Author Share Posted November 2, 2014 And please don't feel bad about trying to break my experiment. I already knew you were going to throw that out there lol. I welcome a discussion on this. I didn't just clean those darn cuvettes all this time for "just fun". I hate cleaning cuvettes because to do it right takes a second. The last step of the experiment is to stop by Ty's and test my meter against his Hanna standard solution to see how well my meter is calibrated. 2 Quote Link to comment Share on other sites More sharing options...
Bpb Posted November 3, 2014 Share Posted November 3, 2014 Having used both the phosphorous and the phosphate meters, I can say it takes me at least 2 full minutes of vigorous shaking to get the reagent MOSTLY dissolved. I don't see how it can be done in one minute Quote Link to comment Share on other sites More sharing options...
FarmerTy Posted November 3, 2014 Share Posted November 3, 2014 Great experiment Reburn! Way to help advance the hobby! Just let me know when you are available and you can swing by to give that reference standard a try. Several things that I have observed over the years from using these Hanna meters (both phosphate and phosporus). Batch quality has always been an issue with the powdered reagents so I'd highly recommend testing the same water with one packet from your old box and one packet from your new box to compare the reading differential. If you already have the phosphate meter, no need to go out and get the phosphorus meter instead. On that note however, the phosporus one does read in the range we as marine enthusiasts care more about. The best way I have found to maximize your time for the reagent to dissolve is exactly what Victoly said, after it asks for C2 (the curvette with the reagent dissolved into it), you have roughly 1.5 mins before it auto shuts off. I take that 1.5 mins to dump in my reagent (I've already pre-prepared the packet of reagent for this step), invert the tube continuously (don't shake vigorously or you will introduce microbubbles), and right when my 1.5 mins is almost up, I'll then depress the button and hold it down to initiate the 3:00 countdown. I continue to invert the tube over and over during this process. Typically, all of my reagent is dissolved by the time it reaches 2:00 to 1:30. Then I lay the tube horizontally and run the large air bubble along the sides of the glass to discharge the microbubbles that have accumulated on the glass walls during the inverting/mixing process. Lastly, I put the curvette into the meter and wait for the countdown to cease and read my result. Hope that helps! Sent via Tapatalk Quote Link to comment Share on other sites More sharing options...
Bpb Posted November 3, 2014 Share Posted November 3, 2014 I was under the impression the meter was reading during the 3 minutes, not just waiting to take a snapshot reading at the end Quote Link to comment Share on other sites More sharing options...
victoly Posted November 3, 2014 Share Posted November 3, 2014 I've opened it with the timer on before and never saw the green diode until the end of the countdown. Quote Link to comment Share on other sites More sharing options...
Bpb Posted November 3, 2014 Share Posted November 3, 2014 Good to know. Nice avatar. Good to see another KOTH fan. That looks like the Nebrasky episode. Quote Link to comment Share on other sites More sharing options...
FarmerTy Posted November 3, 2014 Share Posted November 3, 2014 Agreed, I've observed the same thing and believe it to only read at the end of the counter. Quote Link to comment Share on other sites More sharing options...
Reburn Posted November 3, 2014 Author Share Posted November 3, 2014 Both Ty and Victoly have made valid points. I kinda knew that the C1 C2 method would come into contention. Since I discarded the premixed phosphate water I will be running this experiment in its entirety again when I have the time. I will run the experiment as I did with the C1 C2 method in the clean water first, then the C1 C1 method on the clean water. Then the C1 C2 method on the phosphate water, then the C1 C1 method on the phosphate water. As above I will use the procedures as outline in the lab procedures post by Victoly. What I hope to achieve is proving that the test can be done repeatly with little variance and that the C1 C2 method method is as acurate within the range of the plus/minus .04ppm of the meter and the C1 C1 method. I still have plenty of the 0ppm source water and the phosphorus dosing method will remain the same. One thing I am going to do is wear latex exam gloves so when doing the C1 C1 method I can eliminate having to do a ethanol wipe on the outside of the cuvette to eliminate any finger prints. I will just wipe with a microfiber cloth as I normally do. Is there anything else that I seem to be missing that should be considered? Quote Link to comment Share on other sites More sharing options...
Reburn Posted November 3, 2014 Author Share Posted November 3, 2014 Yes I will use the same cuvette for all the C1 C1 tests. Quote Link to comment Share on other sites More sharing options...
FarmerTy Posted November 3, 2014 Share Posted November 3, 2014 Reburn, I am impressed with your desire to be thorough. From a professional perspective of sampling for submittal to labs for a report used by government entities, Victoly and I had to adhere to some pretty stringent sampling protocols as well as documentation. From a hobbiest perspective however, I honestly think you aren't going to get too much of a discrepancy from using the C1 to C2 or C1 to C1 method. It's ingrained in my head to use the same cuvette as the blank and always face it the same direction to avoid any discrepancies in glass consistency effecting the results but in our hobbiest world, I really don't think it matters. Victoly may gasp (I've failed you!) but I carry this blasé attitude to my other sampling protocols and rinse with tap water instead of RO for cleaning the cuvettes and vials used for sampling. I don't bother storing the cuvettes in RO water either and it'll be a miracle if I even wipe the vials dry after I clean them. Just a good hard flick to get rid of water in the vial suffices for me. Are my results reproducible, yes. Do they have a possibility of a slight margin of error due to my 'laxed testing procedures, yes. Do I worry about reading 420 ppm of Ca versus 430 ppm, no. Will it affect anything in my tank because of the discrepency? Probably not... I surveyed my acros and they generally responded with 420 ppm Ca is just as good as 430 ppm Ca for them. Just like 0.03 ppm of PO4 or 0.07 ppm of PO4, while a higher margin of error in regards to how it'll affect our corals (mainly us SPS guys), to me I'm just aiming for the ballpark and it's not worth the extra effort of such stringent lab grade testing procedures. I often test 2-3x a week, it's already tedious enough so I don't want to make it that much more difficult on myself. Just wanted to share my thoughts on it. In a perfect world, I'd always want the most accurate data as I can possibly get but in this scenario and hobby, the amount of work versus how much marginally better data I'm getting is just not worth it to this lazy reefer. :-) Sent via Tapatalk Quote Link to comment Share on other sites More sharing options...
victoly Posted November 3, 2014 Share Posted November 3, 2014 I tend to agree with you overall Ty, I just couldn't personally get reproduceability unless i went hardcore lab nut for phosphate. And even now I get results that make me scratch my head. The problem with phosphate photometry is that we're sitting way down at the bottom of the scale, and lab error isn't always linear (i.e., you might have 2x error in our range, while 4x error in a different range which averages to the stated error of 3x). I just don't know how they calculate their error and how much of it they chalk up to average hobbyist use vs. excel nut hydrogeologist use. For fun, i looked up the EPA phosphate method, and it's very, very similar to the method we use. They use multiple steps and reagents instead of just one, which may be where we get some error. I'm gonna take another look at it and see what the epa method error is. Quote Link to comment Share on other sites More sharing options...
FarmerTy Posted November 3, 2014 Share Posted November 3, 2014 Sometimes I just want to throw my Hanna meter into the ocean! Their batch quality on reagents drives me nuts, to the point that I almost don't trust anything coming out of it. I'm curious as to what discrepency you find between the EPA's method error and Hanna's. I wish I still had some of my old lab contacts so I could pick their brain about it. I still enjoy your debate you brought up regarding the interference of macro algaes into the result of phosphates. It's been a thought in the back of my head for some time now and it helps bring the issue to light. What does this phosphate result really mean? How much does macro algae in the tank affect phosphate results? Quote Link to comment Share on other sites More sharing options...
Bpb Posted November 3, 2014 Share Posted November 3, 2014 Lol man you guys are really making me want to do some water tests!!! I think I'll try the c1 c1 method on phosphate tonight after work. I always use latex gloves (pretty much endless supply) and my sham wow to wipe down the cuvettes before putting into the meter. Only difference between Red Sea tests and Hanna meter tests is I don't store the Hanna cuvettes in RODI. I rinse them in vinegar and RODI and store them upside down to dry. Whereas with the Red Sea ones, I rinse and scrub with a tooth brush and store them full of rodi Quote Link to comment Share on other sites More sharing options...
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