All Discussions Tagged 'TDS' - Aquaponic Gardening2024-03-28T18:25:34Zhttps://aquaponicgardening.ning.com/forum/topic/listForTag?tag=TDS&feed=yes&xn_auth=noMeasuring TDStag:aquaponicgardening.ning.com,2017-06-12:4778851:Topic:6420162017-06-12T17:04:41.997ZDavid Leithauserhttps://aquaponicgardening.ning.com/profile/DavidLeithauser
<p>I am trying to build a simple device to measure total dissolved solids (TDS) in water by measuring electric conductivity (EC). I have two metal plates in the water. I run a current through the water, and use a voltage divider to measure the resistance. I take the reciprocal of the resistance to be the EC. The EC goes up as the PPM TDS goes up. So far, so good. The problem is that everything I have read says that EC should go up linearly with TDS. The general figure is that TDS PPM = 500…</p>
<p>I am trying to build a simple device to measure total dissolved solids (TDS) in water by measuring electric conductivity (EC). I have two metal plates in the water. I run a current through the water, and use a voltage divider to measure the resistance. I take the reciprocal of the resistance to be the EC. The EC goes up as the PPM TDS goes up. So far, so good. The problem is that everything I have read says that EC should go up linearly with TDS. The general figure is that TDS PPM = 500 times EC. The exact number is not important, because I am not calibrating the EC to standard units, but the point is that PPM is supposed to go up linearly with EC. The problem is that in my experiments, it is not linear. I get a ratio of 35 at 14 PPM, 25 at 32 PPM, 10 at 162 PPM, and 8 at 214 PPM. Can anyone point out the flaw in my system?</p> pH Mysterytag:aquaponicgardening.ning.com,2012-06-21:4778851:Topic:3533872012-06-21T18:02:56.420ZAmanda Plantehttps://aquaponicgardening.ning.com/profile/AmandaPlante
<p>I've had a lot of help with this from a question I posted on a recent photo upload, but now I think the discussion is getting to the size where it really needs it's own thread. Here's a <a href="http://aquaponicscommunity.com/photo/blushing-berries-3?commentId=4778851%3AComment%3A353286&xg_source=msg_com_photo" target="_self">LINK</a> to what's already been said. Thank in advance for all your help.</p>
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<p><strong>Background</strong>: Our aquaponic system is located at a local…</p>
<p>I've had a lot of help with this from a question I posted on a recent photo upload, but now I think the discussion is getting to the size where it really needs it's own thread. Here's a <a href="http://aquaponicscommunity.com/photo/blushing-berries-3?commentId=4778851%3AComment%3A353286&xg_source=msg_com_photo" target="_self">LINK</a> to what's already been said. Thank in advance for all your help.</p>
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<p><strong>Background</strong>: Our aquaponic system is located at a local high school. We have 50 peppers, 100 strawberries growing in clay beads, and 10 goldfish living in two 100 gal reservoirs. We started off with more fish, but after a few attempts we decided to be content for the time being with the 10 survivors. Our pH generally runs between 7.3 and 7.6. It's a little higher than I'd like, but the water was resistant to being altered by neutralizers and pH lowering products.</p>
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<p><strong>Problem</strong>: Two weeks ago, I cleaned and calibrated our Hanna meter. I verified the efficacy of the meter with a manual water test kit. The TDS was reading below 200, so I added about an ounce of an organic liquid fertilizer (more info about that product below) to the reservoir. I've done this before, and this has had a negligible effect on the pH. That day, as soon as I added the fertilizer, the pH jumped from 7.4 to 8.1! </p>
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<p><strong>Treatment</strong>: Since then, we've gone through two bottles of "pH Down" and the rest of our water neutralizer. When we add the pH Down, the pH will drop from above 8.0 to about 7.6 immediately. Within an hour of application, the pH will begin to climb. Within 3 hours of application, the pH will be back where it started. I spoke with the company that makes pH Down, and their advice was to continue adding the product until the pH actually stays down.</p>
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<p><strong>Tests</strong>: Based on a suggestion on the photo (link at beginning), a did a "vinegar test" of the clay beads the plants grow in and of the aquarium rocks that line the bottom of the reservoirs. Neither resulted in any bubbling or frothing when added to the vinegar. Earlier today I also did the following tests:</p>
<p>- Ammonium: 0 ppm</p>
<p>- Nitrite: 0 ppm</p>
<p>- Nitrate: 20 ppm</p>
<p>- TDS: 380</p>
<p>- Temperature: 88.0 F</p>
<p>- Water Source pH: 7.0</p>
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<p><strong>Fertilizer</strong>: Since the spike occurred at the exact moment I added the fertilizer two weeks ago and hasn't come down since, it seems that more information about the product I use would be in order. </p>
<p>The fertilizer is Fox Farm "Grow Big" Hydroponic Liquid Fertilizer: <a rel="nofollow" href="http://foxfarmfertilizer.com/products_liqfert2.html" target="_blank">http://foxfarmfertilizer.com/products_liqfert2.html</a> . Until this last application, adding fertilizer had an insignificant effect on pH.</p>
<p>Although our TDS was low when we first started the system, and although "Grow Big" is an organic product, I was initially reluctant to add the product to the water with the fish. While the students were out for spring break, we wouldn't have access to take care of the fish. We ended up taking the fish to our office for a vacation, and I tested out the fertilizer in the system before the break. After the break the plants looked great. </p>
<p>Come to find out, we had missed a fish who was doing really well despite going hungry for a week and living in the dark in water that had fertilizer. Ever since then, I've added an ounce of fertilizer every time the TDS drops below 200. But I would never apply more often than once every two weeks.</p>
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<p>I'm really not sure what to do at this point. The fish seem ok, but the plants are really starting to get stressed out by the high pH. Thoughts?</p> Assimilation of Nutrientstag:aquaponicgardening.ning.com,2012-06-08:4778851:Topic:3476662012-06-08T21:38:59.526ZBob Campbellhttps://aquaponicgardening.ning.com/profile/BobCampbell
<p>In an attempt to better understand nutrient assimilation I began searching the internet, and taking notes. I think I have a pretty good feel for water chemistry now, and believe I have connected the dots in an easy to understand way, I hope this helps others understand the complex interactions involved.</p>
<p>I posted my notes on my Blog, and would appreciate your input and corrections if I have made any mistakes.…<br></br></p>
<p>In an attempt to better understand nutrient assimilation I began searching the internet, and taking notes. I think I have a pretty good feel for water chemistry now, and believe I have connected the dots in an easy to understand way, I hope this helps others understand the complex interactions involved.</p>
<p>I posted my notes on my Blog, and would appreciate your input and corrections if I have made any mistakes.<br/><a href="http://chicoaquaponic.blogspot.com/2012/06/assimilation-of-nutrients.html" target="_blank">http://chicoaquaponic.blogspot.com/2012/06/assimilation-of-nutrients.html</a></p>