Hey friends, I wanted to share my recent publication. On what I believe to be some pretty revolutionary concepts to optimizing biological health in aquatic system.
Here’s a link if you’re interested. I would love to hear your thoughts!
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Thanks for pushing it forward. Adding to my read list.
Interesting, but the short link seems to be broken.
@romor001 Interesting it works for me. Here is the direct unshorted link for the download Form
Please let me know if it works for you!
This worked fine. Looks like buff.ly is down or not available from my region.
Thanks for the link!
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Does the article have, or is it going to get a DOI?
From page 44 regardin pH changes for hygiene:
" … although it is important to not create
a rapid change exceeding (+/- 0.2 units pH/ day) of the culture
water to minimize animal stress or disrupt beneficial microbial
communities in the system."
This might be a good intention, but hard to realize in RAS systems. One practitioner we know even takes a totally different approach, generating a pronunouced pH step of at least one pH stage by adding hydrated CaOH for pH management. According to him this pH bump is tolerable for his catfish, but causes exoparasites like Gyrodactylus to release from the gills giving the opportunity to be swept away from the fish.
Regarding the microbial community on the biofilter I honestly think we are playing live evolution on the substrate surface anyway. This whole “pH optimum for nitrification bacteria is around pH 8” is of little substance to my opinion. If I keep the pH below that, those strains that tolerate lower pH will have an advantage and my system will select for them. Within certain boundaries of course. Can’t sweep with conditions that kill everything.
We see the same thing with multi resistant bacteria through constant evolutionary pressure and selection with antibiotics. Those that survive are going to be the generation of tomorrow.
I know, that is what you are describing in the article. And I agree.
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Thank you for reading and sharing your thoughts! I agree that in RAS maintaining a pH change of Less than 0.2 units per day could be difficult. In the aquaponic systems I’ve managed we have stayed pretty stable with pH drop per day (0.1-0.2 units) note: They have all been in areas with hard water.
I wouldn’t promote such large pH swings with out a just cause (ex getting rid of parasite) because the extra stress to the system. But your right that alot of species of fish would tolerate a pH change of at least 1. in a pond system for example large pH swings can be common daily.
The goal if we have the ability though is to keep the biology within it’s physiological comfort zone as much as possible and if we do that and use practices that promote a reducing but not overly reduced system (ex feed a good diet) then the fish (plant, microorganisms) will be better able to handle stress events (like a large pH change, or pest). When they occur.
The pH, Eh, and Ec Nexus I describe though is like Pandoras box though. There is so much unknown. So I hope others continue the research in a more scientific capacity.
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Yup. The lowest pH system I have ever operated stabilized around 4.8-5.0 and while I lost some tilapia the ones that survived survived and the system grow hundreds of pounds of aloe vera, orchids, trees.
It’s survival of the survivalist out there.
FYI for anyone reading I wouldn’t recommend others to operate their system that low of a pH unless you have an experimental system.
Not to mention at a lower pH the TAN is mostly in the form of ammonium and non toxic to fish.
kinda of surprised to see EC used at all in aquaponics given how instable the range is in AP vs other methods. its to variable in AP to be any kind of useful metric.
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Have you read the paper yet? I like to use as EC as an indicator metric but your right that it isn’t what I would consider a manageable metric yet.
As proposed in the paper though by combining pH, Eh, and EC into one metric then it becomes much more usable and that new metric would become probably the most valuable metric for biological organism regardless of if they live in the soil, land, air or aquatic environment
The pH, Eh, EC Nexus affects biology even at the cellular level
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