Ben Posted January 24, 2006 Share Posted January 24, 2006 Hi all, I have 3 x KH test kits, 2 x GH test kits, 1 x pH test kit and 1 x DSE digital pH tester. I have measured the pH, KH and GH in my bank of 2 x 6x2x2’s on a 4x18x18 sump. Below are the results. Sera KH test kit measured 30dKH or 537ppm Hagen KH test kit measured 350ppm or 19.6dKH Aquarium Pharmaceuticals KH test kit measured 42dKH or 751.8ppm Hagen GH test kit measured 140ppm or 7.84dKH Aquarium Pharmaceuticals GH test kit measured 7dGH or 125.3ppm Aquarium Pharmaceuticals pH test kit measured a pH of 8.4 (Test kits Max = 8.8) DSE digital pH tester measured a pH of 8.42 So taking an average my tanks KH = 30.5dKh or 543.86ppm GH = 7.42dKH or 132.3ppm and pH = 8.42 I found a great site to do the conversions from dKH to ppm or ppm to dKH. Site is http://www.hagen.com/usa/aquatic/gh_kh_conv_cal.cfm So my question is how come my KH value is so high and my pH is still only 8.4? Why do you think there is such a difference in the KH test kits? I can under stand the difference in the Sera test kit and the Hagen test kit (could be the slight difference in 5ml of water to be tested) but not the 42dkh reading by the Aquarium Pharmaceuticals test kit. Link to comment Share on other sites More sharing options...
Nigel Posted January 24, 2006 Share Posted January 24, 2006 How old are the test kits as they have a limited shelf life. Also sometimes it could be something else in the tank making the readings go hay wire. Also with the PH meters have they been calibrated. Also you should never put them in the aquarium you get a clean glass fill it with aquarium water and then put the PH meter in that. Link to comment Share on other sites More sharing options...
Ben Posted January 24, 2006 Author Share Posted January 24, 2006 How old are the test kits The Sera test kit is about 18 month old. The Hagen about 5years and the Aquarium Pharmaceuticals a few months. I was thinking it could be the age of them but the youngest one is the one giving the strangest results. Also with the PH meters have they been calibrated. The digital pH meter was calibrated before I used it. Also you should never put them in the aquarium you get a clean glass fill it with aquarium water and then put the PH meter in that. I didn't know that. Nothing about it on the paperwork that came with it either. Thanks for the heads up. I am going to take a sample of water to a LFS that does testing. I will let you know what they say as a matter of interest. Link to comment Share on other sites More sharing options...
Markus13 Posted January 24, 2006 Share Posted January 24, 2006 Test kit reagens only have an effective lifespan of 9-12 months once opened Link to comment Share on other sites More sharing options...
Brett4Perth Posted January 24, 2006 Share Posted January 24, 2006 I suspect that most of these hardness test kits are lucky to be within 20% of the "true" result. The kH tests do seem to be particularly disparate though. pH of 8.4. What did you expect it to be? Cheers Brett Link to comment Share on other sites More sharing options...
Nigel Posted January 24, 2006 Share Posted January 24, 2006 How old are the test kits The Sera test kit is about 18 month old. The Hagen about 5years and the Aquarium Pharmaceuticals a few months. I was thinking it could be the age of them but the youngest one is the one giving the strangest results. Also with the PH meters have they been calibrated. The digital pH meter was calibrated before I used it. Also you should never put them in the aquarium you get a clean glass fill it with aquarium water and then put the PH meter in that. I didn't know that. Nothing about it on the paperwork that came with it either. Thanks for the heads up. I am going to take a sample of water to a LFS that does testing. I will let you know what they say as a matter of interest. ← Most of the test kits are to old Ben and I have my doubts about the PH meter. So it will be interesting what the LFS testing shows. Link to comment Share on other sites More sharing options...
Ben Posted January 24, 2006 Author Share Posted January 24, 2006 pH of 8.4. What did you expect it to be? I would have thought with it still being on 8.4 that a KH of about 12 - 15 dKH. A pH of 9.2 should return a reading of around 18dKH I believe. Link to comment Share on other sites More sharing options...
Ben Posted January 28, 2006 Author Share Posted January 28, 2006 I am going to take a sample of water to a LFS that does testing. I will let you know what they say as a matter of interest. Ok I went to the LFS today will a bottle of tank water. Here are their findings. pH 8.8 KH 230ppm or 13dKH GH 160ppm or 9dGH Needless to say I bought some new test kits. Link to comment Share on other sites More sharing options...
Nigel Posted January 28, 2006 Share Posted January 28, 2006 Well Ben there you go everything is just what it should be. The only thing the KH is a bit low maybe bring it up to about 280ppm or 16 dkh. Link to comment Share on other sites More sharing options...
Ben Posted January 28, 2006 Author Share Posted January 28, 2006 Yer thanks Nigel. I just gave the bank a hit with Seachem salt and Tang buffer. Will give it a few hrs and measure again. Should be spot on then. Link to comment Share on other sites More sharing options...
trofius Posted February 1, 2006 Share Posted February 1, 2006 Ben, Kh alone will not boost your pH higher As Kh is just carbonate hardness, you could add as much bicarb as you want, half fill the tank with it, the pH will not rise above about 8.2-8.4, in fact it could just result in a pH crash if the temp gets too high....! other carbonates will get it a tad higher but not up to the 9+, hydroxide salts, and other alkalying agents are needed this is why the tang buffers work better trthan bicarb and calcium carbonate alone Link to comment Share on other sites More sharing options...
Jim Posted February 2, 2006 Share Posted February 2, 2006 Seachem tang buffer maintaines a PH of 9.2 to 9.4 Link to comment Share on other sites More sharing options...
Ben Posted February 2, 2006 Author Share Posted February 2, 2006 this is why the tang buffers work better trthan bicarb and calcium carbonate alone Hi Mick, I only add Seachem Tang Buffer and Seachem Salt to my tanks. Hi Jim, Mine isn't there yet. Getting close. 8.8 last measure. Link to comment Share on other sites More sharing options...
Nigel Posted February 2, 2006 Share Posted February 2, 2006 I have never worried about the PH if the KH is up about 15-18 dKH and you have pleanty of oxygen in the tank then the PH is not importent as it will be up around 8.9-9.0. Link to comment Share on other sites More sharing options...
Ben Posted February 2, 2006 Author Share Posted February 2, 2006 Its just quicker to measure the pH apposed to the KH... Link to comment Share on other sites More sharing options...
Ben Posted February 4, 2006 Author Share Posted February 4, 2006 I just measured the KH and GH again with my new test kits. My KH measured 300ppm . My GH, however, measured 600ppm. Could it really be this high? I will measure my tap water in the morning and let you know. I can only imagin it is high. Link to comment Share on other sites More sharing options...
Ben Posted February 4, 2006 Author Share Posted February 4, 2006 Ok, I just measured my tap water. KH = 10ppm and GH = 60ppm. Any idea's. Link to comment Share on other sites More sharing options...
Nigel Posted February 4, 2006 Share Posted February 4, 2006 What is the substate in the tank and what sort of rocks if any? Link to comment Share on other sites More sharing options...
Ben Posted February 5, 2006 Author Share Posted February 5, 2006 Currently there a 2 x 6x2x2's on the system. Both have size 2 coral sand substrate. I am about to put a 3rd tank on the bank, a 6x2x18. I will have coral substrate also. The rocks in the tanks are fake loges etc, I would presume they have no adverse affects on the buffering of the tanks as they are made for fish tanks. Link to comment Share on other sites More sharing options...
Nigel Posted February 5, 2006 Share Posted February 5, 2006 Currently there a 2 x 6x2x2's on the system. Both have size 2 coral sand substrate. I am about to put a 3rd tank on the bank, a 6x2x18. I will have coral substrate also. The rocks in the tanks are fake loges etc. ← There is the problem Ben you have to take out the Coral Sand and then the GH will stabilize. I tried tell every one before you cant have a reactive substrate and use these buffers and cichlid lake salts. Link to comment Share on other sites More sharing options...
Ben Posted February 5, 2006 Author Share Posted February 5, 2006 Bugger Link to comment Share on other sites More sharing options...
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