jejenkins Posted February 1, 2009 Share Posted February 1, 2009 Just got the calibration fluid in and calibrated. Then checked my PPT and it is 45! I'm going to dig out my hydrometer and see what it shows, but if it verifies, what is the best method to bring her down. My thoughts are doing 10-20% WC every other day with the fresh SW mixed to PPT of 35. This will eventually bring it down. Everything in the tank is doing fine, do have cleaner shrimp (most sensitive to SG changes as I understand) clowns, goby, mushrooms, ricordea, frogspawn, candy cane. What are others methods to bring this down? Link to comment
jejenkins Posted February 1, 2009 Author Share Posted February 1, 2009 OK so got out the old hydrometer. It reads PPT of 33.5 and my refractometer after using the calibration fluid says PPT of 45 still. I had some SW mixing for a water change and mixed as usual. The hydrometer reads PPT of 26.5 and refractometer reads PPT of 40. I am leaning to believe the hydrometer as I usually mix the salt initially a little low and then add a little before the water change to get it up to 35. (easier to add salt than take away Anyway, I reused the calibration fluid which says it is at 35ppt and the refractometer is dead on 35ppt (from previously calibrating it). So what should I do? Could the calibration fluid be wrong? I thought about using some RO/DI water and seeing where it comes out. If at zero, then I will go by the refractometer but if it comes out around 8-10, I'm guessing the calibration fluid is faulty. Thanks for any input. Jon Link to comment
The Propagator Posted February 2, 2009 Share Posted February 2, 2009 Recalibrate you refractometer and try again. This time allow it time to adjust to room temp to give you a treu reading. Then try and calibrate it using nothing but RO water at room temp. ( and YES swingarms CAN be that far off versus a refractometers reading. Especially if its redsea, Deep six. The only ones even half way accurate are Instant ocean. ) Its very unusual for a refracter to be wrong over a swing arm hydrometer if its been calibrated correctly. Link to comment
jejenkins Posted February 2, 2009 Author Share Posted February 2, 2009 THanks prop, I did recalibrate with fluid waiting til room temp. Then I measure RO/DI water with the refractometer and it showed 10ppt. I'm thinking is should read close to zero. It always had before. So with my mix per instructions (Red Sea pro) measuing near 45, my tank measuring near 45 and RO/DI measuring 10ppt. I almost have to believe the calibration fluid is off by 10ppt. I contacted the seller and let him know my concerns, haven't heard back yet. The only respectable LFS is about 45minutes away, my next chance I'm going to take my refractometer up there and compare. I went ahead and claibrated the refractometer off of RO/DI and set to zero and adjusted my SW mix off that for now. That is where the refracto has been calibrated and what I have been using for a couple of months now with my livestock doing well. I'm just hesitant to bump my PPT by 10 without knowing for sure. Plus when mixing per Red Sea instructions and calibrated off of RO/DI it is coming up 33-34 ppt. Gotta be closer. I'll let you know what I find out for sure and I'll take the calibration fluid to the LFS and let them test. If it comes up bad.......I'll warn folks of the seller (on ebay, and not to say he won't address it, just haven't heard back yet). THanks again Link to comment
The Propagator Posted February 2, 2009 Share Posted February 2, 2009 It should read ZERO specific gravity in your RO water. Not close to but zero. I never trust calibration fluid for anything but PH, and TDS meters honestly. Just calibrate it to your RO/DI water and you will be fine. I guarantee you there is not salt in your RO/DI water. Link to comment
bdare Posted February 5, 2009 Share Posted February 5, 2009 It should read ZERO specific gravity in your RO water. Not close to but zero.I never trust calibration fluid for anything but PH, and TDS meters honestly. Just calibrate it to your RO/DI water and you will be fine. I guarantee you there is not salt in your RO/DI water. Prop... you're looking for a beating aren't you? I understand the issue ole boy is having but.... Link to comment
jejenkins Posted February 5, 2009 Author Share Posted February 5, 2009 It should read ZERO specific gravity in your RO water. Not close to but zero.I never trust calibration fluid for anything but PH, and TDS meters honestly. Just calibrate it to your RO/DI water and you will be fine. I guarantee you there is not salt in your RO/DI water. That's good to know......won't even screw with the calibration fluid. Just use RO/DI then. Thanks Prop Link to comment
bdare Posted February 5, 2009 Share Posted February 5, 2009 That's good to know......won't even screw with the calibration fluid. Just use RO/DI then.Thanks Prop NOOOO!!! I normally back everything Prop says, but he's fallen off his rocker on this one. Just because it matches your hydrometer does not mean you should use RO/DI to calibrate your refractometer. You should ALWAYS use a solution which is closest to what you are measuring to calibrate your equipment. http://reefkeeping.com/issues/2006-12/rhf/index.php Link to comment
The Propagator Posted February 6, 2009 Share Posted February 6, 2009 Malarky. No salt in RO water. Link to comment
bdare Posted February 6, 2009 Share Posted February 6, 2009 Malarky. No salt in RO water. Before you say malarky read the article dude... it's pretty intersting when it comes to individual refractometers. Check out the section on calibration. Link to comment
The Propagator Posted February 7, 2009 Share Posted February 7, 2009 I did and I still don't follow the logic. It even says its fine to use RO/DI water to calibrate your refractometer For many refractometers used by reef aquarists, the manufacturer calls for pure freshwater to be used for calibration. With a perfectly made refractometer (that hasn't changed since its manufacture), that single point calibration at the end of the range (Figure 5) would be adequate, albeit not perfect. A better single point calibration might be performed in the middle of the range being used, and for higher accuracy, more than one calibrating solution would be used. Basically the only way one would change that drastically would be if you took it apart or dropped it... OR You bought a real cheap POS to begin with. The only off set he talks about is if the screw is intentionally moved off the mark that you would use to calibrate it with in the 1st place though LOL ! Well yeah ! That's how you calibrate it in the 1st place, and why you should before each use. I really trust Randy on just about every thing he says but you have to admit some times the guy over complicates the living crap out of the most simple things Most all refractometers now though come out of the same manufacturer in China. The only differences now are aluminum versus metal construction, LED light vs regular, and thumb screw or set screw calibration. The accuracy this suggests you would gain by using a standard versus RO water is pretty much nil in MHO based on real life scenario. Not to many people are going to run out and plop down a bill on a digital scale to calibrate a $40.00 refractometer with the DIY solution. As well not to many people actually trust some one elses pre made standard. I mean provided you didnt purchase a complete POS to begin with and you didn't drop it.... The MOST you would be off calibrating it correctly using RO DI water would be what ? .5 ppm ? Big hairy deal. LOL! You get more then that via evap induced salinity swing each day. Our corals are sensitive but not that damn sensitive ! Link to comment
jejenkins Posted February 8, 2009 Author Share Posted February 8, 2009 Just to clarify guys. I wasn't questioning the value of using calibration fluid, I was questioning the fluid I purchased. Went to LFS tonight. Tested my refractometer with theirs and then they tested the fluid I purchased. I was right! The fluid was 45ppt! So buyer beware of purchasing calibrAtion fluid on ebay. I won't rat on the seller, but I comes in a brown vial. Use with caution. Link to comment
The Propagator Posted February 8, 2009 Share Posted February 8, 2009 Just to clarify guys. I wasn't questioning the value of using calibration fluid, I was questioning the fluid I purchased. Went to LFS tonight. Tested my refractometer with theirs and then they tested the fluid I purchased. I was right! The fluid was 45ppt!So buyer beware of purchasing calibrAtion fluid on ebay. I won't rat on the seller, but I comes in a brown vial. Use with caution. I know you were that's hwy I went on my little tangent about using calibration fluid period for refractometers. Unless they have been dropped or are seriously cheap POS'S there is simply no need to for our purposes. RO/DI water calibration is absolutely fine. Link to comment
jejenkins Posted February 14, 2009 Author Share Posted February 14, 2009 Well I contacted the seller. He got back to me and was grateful as he tested some fluid he had and his came out 25ppt! He said he had switched suppliers and never thought he wouldve had to verify thefluid from the new supplier but he is switching back to original and mailing me out some new when it gets in. I'm just worried about whose gotten the bad fluid and mAy destroy their reef due to the inaccurate fluid already sold. Also, good to know I wasn't crazy in questioning the validity of the fluid. Think the seller was being honest. Ill keep updated if he doesn't follow through just to warn anyone else out there if the order fluid from him. Thanks for the help guys Link to comment
The Propagator Posted February 15, 2009 Share Posted February 15, 2009 I'm tell' ya man. Just calibrate it with RO water and your fine. Then this will never happen again. Link to comment
wombat Posted February 16, 2009 Share Posted February 16, 2009 Sounds to me like you may have gotten a standard for conductivity calibration, not refractive index calibration. You mentioned in your other thread that it was 53.0 mS...is that what it says on the bottle? If so, it is useless for calibrating hydrometers or refractometers but should be used on conductivity meters. I'm tell' ya man. Just calibrate it with RO water and your fine. Then this will never happen again. If you wish to accurately calibrate a device you do it at close to the value measured (35 ppt) as possible. This goes for refractometers, 2 point pH calibration, temperature, etc...... Considering the insanely low expense of proper seawater standards it seems silly to not buy some. Link to comment
The Propagator Posted February 16, 2009 Share Posted February 16, 2009 I'm still stick'n to my guns. No real need for it for our purposes. Link to comment
wombat Posted February 16, 2009 Share Posted February 16, 2009 I'm still stick'n to my guns.No real need for it for our purposes. Some people say that about refractometers and insist hydrometers are plenty accurate enough. Link to comment
The Propagator Posted February 16, 2009 Share Posted February 16, 2009 Floating hydrometers are VERY accurate ;P ( they really are LOL ! ) But seriously though I think we all know I am not one of those people. Link to comment
jejenkins Posted February 16, 2009 Author Share Posted February 16, 2009 I'm tell' ya man. Just calibrate it with RO water and your fine. Then this will never happen again. I'm with you Prop! Just mentioning in case someone else feels the need to use cal fluid. I got my own RO/DI. That test solution is FREE! (well a fraction of a penny anyways) THanks Link to comment
The Propagator Posted February 17, 2009 Share Posted February 17, 2009 What ? LOL! I have always had the best of luck just using plain old RO/DI water. 4 realz mane. Link to comment
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