At how many mV is ORP considered dangerous?

[cherubfish pair]

At how many mV is ORP considered dangerous?

[JetCat USA]

above 450mv

[Billybeau1]

The actual number is not a good indication of whether you are adding dangerous levels of ozone to your tank.

I would not pump more than .5 mg/hr per gallon and make sure the effluent is protected by carbon.

I would be concerned about any number over 400 though.

[JetCat USA]

there are many ways to increase ORP that are unrelated to O3, the question as i understood was about ORP, not O3 additions.

[Billybeau1]

I understand Jet, I just don't want folks thinking they can inject tons of ozone in their tanks if they are at 350. It just doesn't work that way, but I know you know that.

[JetCat USA]

yes and i didn't mean to come across otherwise, just trying to clarify so someone doesn't read it and say 'Oh well sense I'm dumping in some H2O2 (which i only recommend if you KNOW what you're doing and then only with proper testing) and not O3 I'll be fine. also when you use O3 and you keep the ORP up around 400-450 (Hey some people do) if you dose Lugol's you can very quickly drive ORP over 500, i guess they like really sterile tanks

[Billybeau1]

Yes, the actual mv number of the tank itself can be very misleading.

[Boomer]

Yes, not above 450 if using any oxidizing agents and H2O2 is such an agent as is Logul's. 500 mv is were stress starts to set in and can be noticed in some animals, if kept a t 500 mV. If one is using H2O2 you need a O2 test kit or it may be a death wish.

[redox]

I prommis you you dont want to see anything over 500. the crommis go first. I was lucky too save the rest but the crommys were totally wiped out . I held my big trigger in my hand ,he was in a coma. I dumped 200 gallons of water and had a ton of carbon in the water and it slowly dropped back to acceptable levels . I will never let that happen again. It was due to the fact that my orp probe was in the outlet tube of the skimmer and the skimmer feed pump malfunctioned alowing the probe to go dry. Well the set piont was never reached ,while the skimmers venturi pump continued to pull o3 rich air into the skimmer. the skimmer holds about seventy gallons so.....I came home noticed the pump offline and never looked at the orp level and got the feed pump going. Whats up with these crommis their jumping around like frogs. Looked over at the 03 controller 700mv man it all went downhill fast. and the main system only got what the skimmer had inside as far as high level go. it only take a little. once I realized what I had done I dumped the contents of the skimmer to get rid of the bad water. forgot to mention the nathans green hand that i had raised from a frag melted away

[mnestroy]

You say to inject just 5mg/hr but how accurate can that be.

There is no way of measuring how much mg/hr ozone is coming out of home units. My unit claims to produce 100mg/hr and has an adjustment, which is far from accurate (0 - 100%).

Now throw in humidity. Even fully dry beads will reduce humidity differently based on how humid the air is in your house.

So at any given time how can you be sure you are dosing 5mg and not 25mg, or even 1mg?

Be nice if there was an accurate way to measure it, to me 2mg/hr smells the same as 100mg.

[cherubfish pair]

Originally posted by JetCat USA
there are many ways to increase ORP that are unrelated to O3, the question as i understood was about ORP, not O3 additions.

Yes, you understood the question correctly.

I am finding the subject of ozone use in the hobby to be fascinating and overwhelming. I am finding a lot of information about it on wetwebmedia.com.

[skriz]

I keep mine between 380-400. I get a little worried if it hits 400.

[Boomer]

mnestroy

You are 100% correct. And then thre is alos flow rate. It is a starting gauge, .3- .5 mg / hr / gal, is where you set the dial. You then go form there.

If the tank has 100 net gals then .3-.5 x 100 = 30-50 is the setting on the dial. Those that do not have dials on them to control the ozone are another issue and I don't care for such units. All you can do with those is set the controller to a level say 25 mV above the current tank level and then slowly raise it by turning up the set point on the controller, 25 mV increments at a time /wk.

There are ozone detectors/sniffers if one has lots of money

[Billybeau1]

Yes and humidity plays a big roll, as it can cut ozone production almost in half. Whether or not you use an air dryer is a big factor in actual ozone production.

One must experiment very carefully until you get comfortable with the additions.

[benf]

Originally posted by mnestroy

Be nice if there was an accurate way to measure it, to me 2mg/hr smells the same as 100mg.

I agree...my ozone unit is adjustable, but doesnt have a mg scale to know how much you are putting thru it. I have been relying on ORP readings, visual, and smell to the best of my ability. I am using the ozone from Clearwater Tech.

[cherubfish pair]

So what kind of molecules produce a high ORP? I thought O3 has a very short half-life?

[JetCat USA]

Originally posted by cherubfish pair
So what kind of molecules produce a high ORP? I thought O3 has a very short half-life?

any oxidizer will increase ORP. O2/O3/Iodine/Bleach/H2O2/etc....

[cherubfish pair]

When does O2 become an oxidizer in sea water?

[Boomer]

It is always an oxidizer, it is just not as powerful as H2O2, Bleaches, O3 , etc.. The higher the O2 the stronger the oxidizer is. It can start to get bad for aquatic fish and inverts @ 150 % saturation if there to long. A lot depends on Salinity, temp, altitude, and species

[JetCat USA]

any time, oxygen is an oxidizer, at elevated levels it starts burning the gills in fish, at even higher levels it'll sterilize a tank.

[nickts40]

Everyone is right. Ozone is a tricky business and ORP has nothing to do with it. My ORP w/o Ozone is 300-310. I use ozone the first week of every month at 30 mg/hour. It tops off at 340 by the end of the week. The skimmate stinks which is a good thing, the anemone shrinks out of existance and the poweder blue is covered in Ick. I have done this cycle for a year and it does not waiver. Once I tried to go for a month and the SPS corals did not like it to put it mildly. Oxidatiojn is oxidation. In the right quantity for enough time it will kill everything. It's for us to figure out the balance.

[cherubfish pair]

All interesting.

[Boomer]

Ozone is a tricky business and ORP has nothing to do with it

Oh yes it does Ozone can raise your OPR very high and to deadly levels.

[JetCat USA]

Boom i thought that was a trick post so i didn't bother to comment

[cherubfish pair]

Ok, a pH above 7.0 is an excess of cations? And ORP is kind of like the reactive potential of cations measured in milivolts? Is there a measurable correlation between pH and ORP?