ORP drop after water change

uberlink

Active Member
I did a five gallon water change yesterday morning. Thanks to my new glorious AqauController III, I was able to see that my ORP dropped from about 340 to about 250 immediately after the water change. Why would this happen?
FYI, the water had been prepared and aging with a powerhead for a week or so. I changed it by siphoning water out of the tank and using my Auto Top Off system to draw new saltwater into the sump. This shouldn't have stirred up any organics.
Thoughts?
 

mcbdz

Active Member
I always heard it was the againg of the saltwater that stopped that.
Maybe check the new water before adding next time. Was you ph the same?
 

sly

Active Member
If you have a skimmer, your tank's water will increase ORP over time. Newly added water has not been thoroughly saturated yet until it has passed through the skimmer. When you circulated it with the power head did you allow it to draw in air or did it just stir the water? Unless it added air while mixing, your ORP will be low until it hits the skimmer.
Your tank lights also help to raise the ORP. Bright UV light breaks down oxygen molecules to form ozone which increases ORP as it reacts with the water. Your topoff water was probably in the dark, hence ozone free.
 

geoj

Active Member
REDOX POTENTIAL BASICS (OXIDATION POTENTIAL):Redox Potential (oxidation potential) describes the ability for the loss of an electron by a molecule, atom or ion to the gain of an electron by another molecule, atom or ion. Without this positive Redox Potential many minerals cannot be absorbed and properly assimilated. So it is very important to keep a proper Redox Potential (-300 to -350mV) via proper dissolved oxygen levels, UV Sterilization, and proper electrolyte levels (such as magnesium).Oxidation describes the loss of an electron by a molecule, atom or ion Reduction describes the gain of an electron by a molecule, atom or ion The above is a simplification of the process, and much more needs to be considered, please read on.Oxidized Water:Oxidized water with its Redox potential of +700 to +800 mV is an oxidizing agent that can withdraw electrons from bacteria and kill them. The oxidized water can be used to clean hands, sterilize utensils, and treat minor wounds. Here are a few oxidizers: ozone (O3), hydrogen peroxide (H2O2), chlorine (Cl2) and chloramines (NH2Cl).Reduced Water:Reduced Ionized with a Redox Potential of -250 to -350 mV readily donates its electrons to unusual oxygen radicals and blocks the interaction of the active oxygen with normal molecules. Substances which have the ability to counteract active oxygen by supplying electrons are called scavengers. Reduced water, therefore, can be called scavenging water. Reduced water inhibits excessive fermentation by reducing indirectly metabolites.Here are a few reducers, in other words, elements or processes that transfer electrons to another substance;Magnesium, Sodium, and the process of Photosynthesis involves both oxidation and reducing.
After electrochemical purification water keeps its initial neutral values of pH, but ORP (Oxidation Reduction Potential) of water shifts toward the negative (electrode or reduction) values. The resulting purified water obtains the antioxidant properties with characteristics of pharmacological activity close to the properties of the antioxidant preparations (a -tocopherol, b -carotene, vitamin C etc.). In case of dilution of polyvitamin preparations in electrochemically purified water ORP of mixtures is decreased approximately by 200 - 400 mV in relation to the control solutions with non-treated drinking water. This partially explains how a proper Redox Potential improves the health of the fish or other aquatic organisms as I have observed. Bringing this back to my observations of goldfish aquariums; All aquariums with the same filtration (canister filter with sponge filter), the same feeding schedule and food, even the same basic goldfish (a mix of ryukins and orandas); The aquariums with the quality, properly installed UV Sterilizers (again assuming proper dissolved oxygen levels) not only had less incidence of disease, but general health, appetite, vigor, growth, and water clarity were all improved.
 

acrylic51

Active Member
Originally Posted by Sly
If you have a skimmer, your tank's water will increase ORP over time. Newly added water has not been thoroughly saturated yet until it has passed through the skimmer. When you circulated it with the power head did you allow it to draw in air or did it just stir the water? Unless it added air while mixing, your ORP will be low until it hits the skimmer.
Your tank lights also help to raise the ORP. Bright UV light breaks down oxygen molecules to form ozone which increases ORP as it reacts with the water. Your topoff water was probably in the dark, hence ozone free.
I agree with you Sly
Very good piece GeoJ
 
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