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The pH from our tap is about 8.1, and with the addition of some gravel beds and seaweed extract, it has reached a high of 8.5.

We have two commercial 20,000 Gallon systems. I've been looking into lowering our pH, but I'm having a hard time finding anything in the quantity we need.

Advice from some commercial Aquapons would be greatly appreciated.

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For such a big system I'd suggest going with some strong chemicals, like Hydrochloric Acid. This will be more efficient than dumping a lot of Acetic Acid (vinegar) in your growbeds. Join chemistry, math, and aquaponics  (http://community.theaquaponicsource.com/group/chemistry-math-and-aq...) for some practice with this type of calculations.  

I agree with Eric. HCL may be your best bet. I'm a big fan of it, even for smaller systems. 

Eric...It might be really difficult to actually calculate and have any real confidence that those calculations would transfer smoothly and apply in the real life scenario (many, many variables and overly complicated IMO for an answer that in all likelihood doesn't even apply...). I would suggest just taking a barrel filling it with a known volume of your water...adjust pH keeping track of how much your using of course...(this needs to be done over the course of 4 to 8 hours because of the phenomena refereed to as 'pH bounce'), multiply the amount needed for 20,000 gallons or whatever to get a threshold amount, and go from there...

Well, Vlad, that's where it gets tricky. However, you can add a base amount of HCl to the water, given its chemical composition,and essentially do your best to get it down to the desired pH and such, then add a bit more so you can put it in your FT. However, the pH should move .1 each day until you get down to a desired pH. If this becomes hard, or impossible, then you can try to engineer a solution, but I'll have to mull that over for a bit.

Yeah, if Kevin has fish already then a bit of forethought and leg work inn the math department wouldn't be such a bad idea...For some (no-good ) reason I had made the presumption that he was in the cycling or beginning stages without a fish load and wanted to drop pH for the plants...

With a live fish load to worry about, you do want to kinda be careful about not adjusting pH too quickly, the slower the better (0.1 to 0.3 units per 24hours). Even then you have some 'wiggle room' but with an operation that size and other peoples money at stake you should probably take the cautious route...

So, APguy01, do you have a fish load to worry about and how established is your bacterial colony?

We do have a fish load (about 350 in one system and 200 fish in the other system), and as for bacteria our system has only been running for about 2 weeks.

I was under the impression that nitric acid was the preferred acid to use in aquaponic systems, but I've only found 1 pH down product that is derived from nitric acid, and I was going to look into getting it in a more pure form.

Vlad or Erick, do you have a reliable source for chemicals such has HCL or Nitric Acid?

I dont know about a Leslies, but there are many pool supply stores nearby. I was shying away from traditional pH downs because of our fish load and because I would like to get organically certified in the future.

Randall Wimbish said:

Do you have a Leslies pool supply near you?

This is my first experience starting such a large system, and the commercial systems I worked with in the past were all established and they had a tendency for the pH to drop over time, as opposed to raise. For this reason, we used some calcium carbonate but never really dealt with lowering the pH.

What naturally occurring process lowers the pH in aquaponic systems? Someone suggested getting more plants in the system, and I though of removing 50-75% of the empty rafts to encourage some algae growth (at least temporarily). Would this hurt or help at all?

Thank you for your input gentlemen.

The process is the Nitrogen Cycle in your aquaponic system. The conversion of Ammonium to Nitrate liberates H ions, and since pH is parts Hydrogen (H) this lowers the pH (counter-intuitive, I know). This will eventually, depending on your water sources chemistry, lower the pH to a normal level and then you'll have to buffer it to about 6 or 7.

APguy01 said:

"What naturally occurring process lowers the pH in aquaponic systems? Someone suggested getting more plants in the system..."


First off, nitric acid HNO3 would work well in aquaponics, but it's still not as strong, or as efficient as HCl. There are instructions online for how to make both if you want. I'll try to find some info'. Second, I've never seen HCl anywhere except in High School chemistry classes, and online. I'd have to research more. Vlad gets his at a store where he lives in Serbia.
APguy01 said:

I was under the impression that nitric acid was the preferred acid to use in aquaponic systems, but I've only found 1 pH down product that is derived from nitric acid, and I was going to look into getting it in a more pure form.

Vlad or Erick, do you have a reliable source for chemicals such has HCL or Nitric Acid?

No... Nitric Acid is not the preferred acid to use.... nor are pH down products, which could be all sorts of unknown things

If you are cycling with fish... then Hydrochloric Acid is the preferred acid....

And IMO, is the preferred option even if fishless cycling... and onwards...



APguy01 said:

We do have a fish load (about 350 in one system and 200 fish in the other system), and as for bacteria our system has only been running for about 2 weeks.

 

I was under the impression that nitric acid was the preferred acid to use in aquaponic systems, but I've only found 1 pH down product that is derived from nitric acid, and I was going to look into getting it in a more pure form.

 

Vlad or Erick, do you have a reliable source for chemicals such has HCL or Nitric Acid?

 

 

Yeah, I didn't know how it would work in a aquaponic system. Would excess Nitrate be the problem, or is it anti-bacterial? 
RupertofOZ said:

No... Nitric Acid is not the preferred acid to use.... nor are pH down products, which could be all sorts of unknown things

If you are cycling with fish... then Hydrochloric Acid is the preferred acid....

And IMO, is the preferred option even if fishless cycling... and onwards...

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