Aquaponic Gardening

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Hello Aquaponics Community!

I go to Westminster College in Salt Lake City and our school is trying to get a large utility aquaponics system on campus. One of the questions that I have stumbled upon many times is if I should try and avoid using tap water because it is slightly basic. 

The pH of our tap water is approx. 8.3 and I suspect it is because of limestone in the mountains where our water comes from (springs mostly). The compound Calcium Carbonate may be acting as a buffer in the system making the pH very stable and high. 

I have a small 10 gallon system currently for experimentation, I have been told, when setting up a new system, not to mess with the pH because the biology is sensitive to large changes, however, I notice my plant growth is somewhat minimal. I came across a problem of dying leaves which I suspected was from nutrient burn or high pH. I simply took out a couple fish and did a water change. We will see what happens within the next couple weeks. 

Everywhere I read I see that aquaponics systems should maintain a pH of 6.8 - 7.0. Should I really consider trying to obtain this? If I have CaCO3 in my water it is acting as a buffering agent. Should I focus on creating a 7.0 environment? 

Any advice helps. Thanks :)


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Here are 74 pages of info on carbonates right here on our forum. HERE



  You should add an acid to combat the basic water of your system.  Depending on the species of fish, if they are from a local stocking buisness chances are that the fish have been bred in the hifh pH water and it probably will not affect the fish, the plants on the other hand will be hindered in nutrient up take because of the high pH.  Aquaponics is a great hobby but there are limitation and pH is one of them.  If you have Silvia burnstiens book, look up the pH and there is a chart showing what pH most plants do the best inn.  (Sorry, I don't have the book in hand at the moment or I would tell you what page to find it on)  There is a condition called nutrient "Nutrient lock-out"  where plants cannot take up nutrients because of high OR low pH.  You need to buffer down the pH for better results, 6.8 - 7.0 is the consensis, try to shoot for that mark.  My plants are doing well with 6.6 - 7.0 so there is a bit of le-way, not much.


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