New member
what will be the most productive way to increase ORP in my tank beside to add an ozone?

my orp has been tested today with my new Reef keeper elite and it show 298... which is low...

i heard also that if i have an UV light than i dont need to have also a ozone.

any opinion about it?


New member
what is your setup? tank size compared to skimmer? when was the last time you changed water? and how is your tank stock?


Master of the 16 hour day
Team RC
Is your skimmer working as well as it could be? This is what happened to my ORP after I installed my new skimmer:


Data shows 5 days worth before I installed my new skimmer, first dip was when I installed it. Seven days later, the second dip was when I did some sump work. ORP goes up over night and down during the day.


New member
i have a 600 gallons tank, 2 skimmers, ASM G4x and G3.

my tank has like 20 fish.. most of them are tangs....

i do a water change every day... i change like 4 gallons of water....


New member
i learned from a lot of people that in that hobby that its a lot better to do a small daily water changes then 1 big one once a month....

so i did it.... and its working so far....


New member
"Most aquarium authors have recommended a range of 300-450 mV. Why? Mostly because the ocean often has ORP in this range, and because these authors have successfully operated aquaria in this range." - REEFKEEPING MAGAZINE

"if I did use it, I would definitely have the ozone on a controller that shut the unit down if the ORP rose above some predetermined value. Setting the shut down at 450 mv sounds like an appropriate precaution to me, with the aquarium typically operating at 350-450 mv." - REEFKEEPING MAGAZINE

(both taken from http://reefkeeping.com/issues/2003-12/rhf/feature/index.php)

if you want to raise the orp, i would first look at your setup (i don't recommend buying more stuff, it just adds more variables)? how much flow is going through your sump? may be there isnt' enough flow? or too much? i know people say that flow through the sump is important.

are you skimming wet or dry?
are you using carbon? or GFO?
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New member
I generally keep my orp at 400mV ...I used to run my ozone through my skimmer...but found I was able to keep my skimmer working better and my orp more stable by running my ozone through a mazzi injector separately...I like this set up much better...I swear by my ozone...

Save the reef- Higher is not necessarily better, you actually want to keep your orp at a stable level around 400mV-425mV anything higher has a potential to harm your contents...

Lifeisfish-If you are running a fish only system then UV is the way to go...but for reef you are better off with ozone.. Bob Fenner has some good articles about the use of ozone and the differences between ozone/UV on WWM...


New member
When Bob Fenner came to our Frag meet in AZ he personally told me to keep my ORP at 375mv, and that's what I do. Works perfect for my tank