ORP and The Freshwater Planted Aquarium

[Christopher Brown]

Morning All!

I've joined an interesting discussion at one of my regular forum haunts and suddenly memories from my saltwater days came flooding back about oxidation reduction potential or ORP.  Applying this to freshwater aquaria is nothing new and has been discussed before among planted aquarium keepers but not that largely popularized.  During some googling has dredged up some interesting results.

http://en.wikipedia.org/wiki/Oxidation_reduction_potential

Those of you with a limnology background probably understand all the various analytics available, especially chemical oxygen demand and biological oxygen demand, COD and BOD respectively.  

http://en.wikipedia.org/wiki/Biological_oxygen_demand

http://en.wikipedia.org/wiki/Chemical_oxygen_demand

For those who don't please have a read.  In essence, the amount of oxygen available to satisfy the various chemical and biochemical processes in a given environment.  ORP is a reflection of this and of many other variables present and returns a single result in mV (millivolts).  Generally speaking 250 mV and up is considered to be an environment in which the various chemical transformations can occur with a specific intensity.  What is behind that single number?  It tells us, that at the moment when the measure was taking, about the hydrogen capacity of the water, as in pH, it gives us an idea of the conductivity & density of the water similar like specific gravity, it tells us the likely concentration of specific gases, like oxygen and CO2 as well as the potential capacities for all these elements as they transition in and out in the various natural cycles that an aquarium, river or like would typically experience.  We can get a general idea of the potential rate of enzymatic reactions of our bacteria and general water & environmental conditions.  We see potentials for many many different variables that a single reading can give us, hence its value.  In short, we can trend and derive algorithms with a good degree of precision that let's us make less general statements as time goes on and understanding improves.  

So, is this something we should be concerned with?  I'm starting to think yes.  There have been a number of experiments among hobbyists and by scientists that would indicate, and I realize I'm about to pour gasoline on a fire here, that a higher ORP strongly correlates with less algae.  Take that statement with a grain of salt though, I'm not suggesting an Easter egg hunt or that there is finally a panacea.  I'm suggesting that an environment more capable of oxidizing and reducing breaks down excess organics (ammonia from protein decay, by products from anaerobic processes) will make it harder for algae to get a foothold, improve overall health of the plants and animals and generally contribute to greater stability and so easier management.  Such an environment while giving algae less of what it needs to proliferate may also be injurious to algae (think toxic) while beneficial to other preferred organisms.

Of course, a strong solution of hydrogen peroxide or glutaraldehyde could be said to have a high ORP but it certainly wouldn't be healthful or beneficial to any living thing so keep that in mind as well.

Thoughts?  

[polukoff .]

Hydrogen peroxide has been the algae killer everyone has been using in San Antonio right now. No one has reported seeing any signs of adverse reactions when spot treating but there is still a lot to be said about it. Would you be available sometime next week to talk with me or possibly in the future to do a meet at your home, I'm really lost in a lot these discussions and I might be able to benefit from seeing some of these experiments you are working on in person and expand my knowledge when it comes to planted tanks. Shoot me your digits if your interested.

--
You received this message because you are subscribed to the Google Groups "Austin Planted Aquarium Keepers" group.
To unsubscribe from this group and stop receiving emails from it, send an email to atx-pak+u...@googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.

[Christopher K. Brown]

I'll be out of town next week and I haven't done any experiments.  What I'm interested in is collecting data from a long period of time.  Ideally, readings from an ORP controller over a period of months in a handy format like Excel or CSV.

ORP and the use of protein skimmers is rare in freshwater planted aquaria, some would reasonably argue that it is superfluous.  In the discussions I'm participating right now, I'm starting think there is something to it.  ORP is a multivariate  statement of ecological health.  I think the discussion here should be what are the upper and lower boundaries?  Do we need more oxygen?  What is the effect of pH, KH, GH and CO2 on ORP?  How much is too much or at least that's where my other cohort is going right now.

For more options, visit https://groups.google.com/d/optout.

--
"You are much better off with no numbers than meaningless ones.  The minute you believe numbers uncritically, that is, without understanding how they're calculated and how well they measure whatever they're supposed to measure, you will generate a breed of employee who will produce numbers and not results.  Your data-processing system will then serve not to describe reality but to lie about it."

-Micheal S. Montalbano