ORP Reading in New DT
- Thread starter AEIOU9
- Start date
Also, in a 4 week old tank, it is waaaaaaayyyyyyy too early to even expect meaningful results. I wouldn't expect any consistant readings for several months.
And in addition to that, now that I think of it, I've found a new ORP probe can often take 1-2 weeks before it gives consistant readings. I bet over the next week, you'll see that number slowly rise. Once it starts rising and falling opposite of your pH values, you can assume it's finally a valid number.
But as David mentions, even with a valid number, it doesn't tell you much. Unless you're running ozone, you should just figure out what your tank's "normal" ORP reading is, and then watch for major variations from that. Any major variation (assuming a mature, stable tank) should make you check around to see if there might be something wrong.
And in addition to that, now that I think of it, I've found a new ORP probe can often take 1-2 weeks before it gives consistant readings. I bet over the next week, you'll see that number slowly rise. Once it starts rising and falling opposite of your pH values, you can assume it's finally a valid number.
But as David mentions, even with a valid number, it doesn't tell you much. Unless you're running ozone, you should just figure out what your tank's "normal" ORP reading is, and then watch for major variations from that. Any major variation (assuming a mature, stable tank) should make you check around to see if there might be something wrong.
Based on Apex instructions the ORP probe does not need to be calibrated. Where are you at in your cycle?
I stuck my ORP probe in the day after adding live rock. Spent a week around 180, then began slowly climbing over the last two weeks. I am sitting between 300 and 320 now--three weeks after the rock was added. ORP really started to climb when my NH4 disappeared but I am still getting trace NO2. pH sat around 7.8 (down to 7.6 at one point) but has climbed to 8.2 now.
My point is that the reason for the off value is most likely that your tank is in a state of flux as bacterial/algal/planktonic populations battle for "equilibrium". My reasoning for the low ORP value is that there is a lot of rot going on and not enough critters yet to process--hence throwing the oxidation-reduction potential of the water all out of whack.
ORP seems sensitive too. When I added my CUC last week ORP dove from 315 to 250 then back up w/in an hour. My read is, that once stable, I can use such a drop in ORP as an indication of an NH4 spike. Other than that, I just have it for giggles (side effect of being a hard science guy I guess).
I stuck my ORP probe in the day after adding live rock. Spent a week around 180, then began slowly climbing over the last two weeks. I am sitting between 300 and 320 now--three weeks after the rock was added. ORP really started to climb when my NH4 disappeared but I am still getting trace NO2. pH sat around 7.8 (down to 7.6 at one point) but has climbed to 8.2 now.
My point is that the reason for the off value is most likely that your tank is in a state of flux as bacterial/algal/planktonic populations battle for "equilibrium". My reasoning for the low ORP value is that there is a lot of rot going on and not enough critters yet to process--hence throwing the oxidation-reduction potential of the water all out of whack.
ORP seems sensitive too. When I added my CUC last week ORP dove from 315 to 250 then back up w/in an hour. My read is, that once stable, I can use such a drop in ORP as an indication of an NH4 spike. Other than that, I just have it for giggles (side effect of being a hard science guy I guess).
Not really. I mean... it *could* mean an ammonia spike, but it could also mean a thousand other things. All a sudden drop in ORP means is that something changed.
Completely agree with all of this. When I recently added an ORP probe to my tank it took almost three weeks for the reading to climb into the 'normal' range. Just look for changes in the reading as an indicator that something has changed.
The tank went through the full cycle. I am starting to see a slow creep in the ORP so between the 1-2 week break in period and your comment, I'm just going to keep an eye on it and not worry about it
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davidfrances
New member
My APEX has been running on my 20+ month old DT for almost 2 weeks now. The reading on my APEX is 183.
My ORP readings from my Red Sea controller (which is still running) are in the 350 range (it's an old probe and pretty encrusted).
I am still waiting for my APEX probe to stabilize
My ORP readings from my Red Sea controller (which is still running) are in the 350 range (it's an old probe and pretty encrusted).
I am still waiting for my APEX probe to stabilize
Yeah, not as straightforward as one would like. Changed carbon yesterday and did not use fine filter floss to trap dust this time--and obviously need to rinse more--and the released dust sent ORP nose diving to 135 w/in the span of a minute or two. Then it climbed back to the 300 level over the next few hours.
Probably the only really reliable use for the ORP reading is to tell you that something is not stable--whatever that is. So at least you have a warning even if you will not be able to figure it out until more obvious signs appear (if they ever do).
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