Ozone Reactor Post Filter Question

[demariners]

So I am setting up a post filter with carbon in it to scrub the air/water mixture. I have a 60 gallon talk. I am wondering how much carbon I should use? The media reactor is big and I wasn't sure if I should put less or more or doesn't matter? Also with the ozone reactor I haven't noticed my ORP going up much. Is this normal with a reactor? Thank you.

 

[Randy Holmes-Farley]

It is more of a factor of the flow, the amount of ozone used, and the type of GAC. having too much isn't that much of a concern. Maybe 2 cups. I used a lot more on my system, because it was handy to do so. I no longer use ozone out of concern for HLLE, although that is only a hypothesized cause.

ORP need not go up much to make the water clearer, which is the goal with ozone. The ORP itself is not the goal.

 

[demariners]

Well shouldn't the ORP go up with ozone? I bought a ORP controller just for that purpose. It is sitting at about 260 ORP and I am told it should be around 350-375. I have had the ozone generator on 24/7 and it still doesn't go up. Maybe I am leaking air or something but I wasn't sure if this was normal?

 

[Randy Holmes-Farley]

No, do not drive the ORP to a preset value. Nothing in your tank cares what the ORP is (at least, I do not know of anything that does, or if they do, what values they prefer).

The reason (and only reason) to use ozone in a reef tank is to make the water clearer and that has nothing to do with ORP. DO NOT be misled by folks claiming that higher ORP is better, and least when it is made higher with added oxidants.

Yes, ORP will go up a little (or a lot, depending on the tank), but ORP probes take time to equilibrate and you just may not notice the rise.

These have more:

Ozone and the Reef Aquarium, Part 1: Chemistry and Biochemistry
http://reefkeeping.com/issues/2006-03/rhf/index.php

Ozone and the Reef Aquarium, Part 2: Equipment and Safety
http://reefkeeping.com/issues/2006-04/rhf/index.php

Ozone and the Reef Aquarium, Part 3: Changes in a Reef Aquarium upon Initiating Ozone
http://reefkeeping.com/issues/2006-05/rhf/index.php


from the second one:

Upon initiating ozone use, some aquarists, like me, see only a small rise in ORP even at recommended levels of ozone. My ORP doesn't rise above 330 mV, for example, and some aquarists' tanks are still in the 200 mV range even after initiating ozone. Others, presumably those who start with a high ORP value, although that may not be the only factor, easily drive their tank's ORP too high if it is not controlled.

So with all that background discussion behind us, here are my recommendations for ORP monitoring and ozone control in reef aquaria using a properly sized ozone generator that appears to be working, and a properly calibrated ORP meter:

1. If the ORP never seems to rise above 375 mV after initiating ozone, do not worry about controlling the ozone or the ORP. Just let it run full out. Also, do not worry about needing a larger generator, assuming it has driven up the ORP by at least 25 mV above where it was before adding ozone. It is likely accomplishing the necessary tasks (such as making the water clearer). Only if some other aspect of ozone use is unsatisfying (e.g., lack of water clarity) would I look for other options such as a larger ozone generator or a better contact chamber.

2. If the ORP starts above 375 mV, or rises there during ozone use, using an ORP controller would be valuable to prevent the ORP from rising too high. Use the controller to shut off the ozone when the ORP rises too high. Another option would be to shut off the air flow to save the dryer's media, but be sure that water cannot flow back into the ozone generator if the air stops. I would set the ORP target somewhat above the baseline ORP in the absence of ozone - at least 350 mV, maybe 400 mV, but never above 450 mV.

 

[demariners]

Thanks for all your advice. So I have an ozotech unit which has a adjustment knob (0-220 mg/hr). For a 60 gallon tank what should I set the mg/hr. I have it set I think for about 50 mg/hr. Again the ORP does not go up at this level. So of course I figured I need to raise it but I have not done anything yet cause I was waiting for your response. I have my ORP controller set for turn off at 400. ORP Probe has been in the tank for about 2 weeks.

 

[demariners]

Front Panel Dial Reading
1
2
3
4
5
Max
Percent Of Max Output
10%
20%
30%
40%
60%
100%
Ozone Output Per Hr.
22 mg
44 mg
88 mg
132 mg
176 mg
220 mg
1.0 gm/m3
1.1 gm/m3
1.3 gm/m3
1.6 gm/m3
2.5 gm/m3
2.8 gm/m3

 

[Randy Holmes-Farley]

I wouldn't raise it higher than where it is now, if you think it might be producing 50 mg/hr. .

 

[demariners]

It is on 3. Which correlates to 88 mg/h according to the chart. I have an air dryer so unless it should be efficient also. I guess there is not way to tell?

 

[Randy Holmes-Farley]

Not easily. But you are using somewhat above the normally recommended levels.

from the above articles:

Gauging how much ozone is necessary is not trivial, and may depend strongly on the desired outcome from dosing ozone, how it is used and the other husbandry practices used in the aquarium. Clearing up yellowing in the water, for example, uses far less ozone than is necessary to sterilize the water. Likewise, a good ozone/water reaction chamber might allow far less ozone to be used than is required by an inefficient use in a skimmer. That being said, most guidelines suggest on the order of 0.3 to 0.5 mg O3/hr/gallon of aquarium water.