Extremely low ORP

[green1181]

Hey Everyone.

I've decided to set up ozone on my 750l reef. Running through air inlet on skimmer. The ORP reading is always under 100, I've purchased some calibration solution and it reads 450mv as it should, I've checked the water out of the tank to maybe isolate any equipment in the tank and it's the same. Performed a large water change since it's been awhile and still under 100. I'm running a cheap weipro 200mg ozone through dessicant. Even if the ozone is weak or not working, shouldnt my ORP be above 100?

Thanks

 

[wvned]

Probably. New tanks have low ORP. Some additives can lower ORP. Tinkering with my sulfur reactor can make mine go negative for a while. Mucking around and stirring up dirt makes it drop like a rock.
But it is an almost meaningless number in and of itself.
Is you water clear and colorless? If so it is working.

 

[griss]

I agree with Ned. I haven't used ozone since the early 1990s and haven't tested ORP in just as long.

 

[kharmaguru]

You could do a small volume test to make sure your ozonater is working, ie., put the probe and ozone tube in a bucket with a gallon of water. It should go off the scale if things are working.