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drew930
10/18/2011, 10:12 PM
Another dumb question . What's ORP ? Should I get an ORP probe ?

EllieSuz
10/18/2011, 10:19 PM
Here is a comprehensive explanation of ORP by Randy Holmes-Farley:

http://www.reefkeeping.com/issues/2003-12/rhf/feature/index.php

drew930
10/18/2011, 10:26 PM
Thanks . I have already read some and will read more .

RussM
10/18/2011, 10:50 PM
In a nutshell... unless you dose ozone, ORP monitoring is not necessary. Personally, I used the modal pH/ORP port for a second pH probe to serve as a failsafe check on the primary pH probe.

swearint
10/19/2011, 09:15 AM
I don't necessarily diasagree with Russ, but I have found the ORP probe to be of value even though I don't use ozone. I had an extended power outage due to a massive storm a few months back. I ran the primary pump from a generator, but left the CL pump unpowered. Then when mains power was restored I did not think about the water that had sat stagnating in the CL loop for a week. When I restarted it, within a few minutes I got a low ORP warning. I don't know that it was severe enough to have hurt anything, but I was able to monitor things closely until it returned to normal over a couple hours. I also use it as a general indicator. It tends to stay within a fairly consistent range, so anything out of the ordinary gets my attention.

Todd

drew930
10/19/2011, 11:50 AM
When you use the second pH probe for the ORP, does it still recognize it as a pH probe ?

RussM
10/19/2011, 12:24 PM
When you use the second pH probe for the ORP, does it still recognize it as a pH probe ?

On the AC3 and full Apex, the second port is selectable to be either pH or ORP. You choose the probe type, then connect the appropriate probe. A pH probe cannot measure ORP and vice versa.

RussM
10/19/2011, 12:28 PM
I don't necessarily diasagree with Russ, but I have found the ORP probe to be of value even though I don't use ozone. I had an extended power outage due to a massive storm a few months back. I ran the primary pump from a generator, but left the CL pump unpowered. Then when mains power was restored I did not think about the water that had sat stagnating in the CL loop for a week. When I restarted it, within a few minutes I got a low ORP warning. I don't know that it was severe enough to have hurt anything, but I was able to monitor things closely until it returned to normal over a couple hours. I also use it as a general indicator. It tends to stay within a fairly consistent range, so anything out of the ordinary gets my attention.

Todd

Good point Todd. A excellent case of what's right for one person isn't neccessarily the best choice for another. In my case, being able to check a pH probe I suspected was flaky had more value to me than measuring ORP. And then I just left that configuration in place.

drew930
10/19/2011, 02:25 PM
Thanks for the replies . I don't think I will ever be adding a ORP probe now that I know what it is

fishmonger007
10/19/2011, 02:33 PM
On the AC3 and full Apex, the second port is selectable to be either pH or ORP. You choose the probe type, then connect the appropriate probe. A pH probe cannot measure ORP and vice versa.


Perfect answer to a lingering question I had. Thanks again :)

fishguy597
10/21/2011, 12:37 PM
what is considered a low orp? from what ive read 250 is on the low end. i put one on my apex because i was considering vodka dosing but not until i do some more research on it first. i have seen my orp at 245 with a ph of 8.05, 225 at a ph of 7.95( low end),248 with 8.05( these are all high and lows through 24 hrs). should i be concerned with this? im not running ozone. should i set my apex to send me an alarm if the orp gets to low and at what reading?

swearint
10/21/2011, 01:22 PM
I don't run ozone, and over several different probes now my tank runs fairly consistently in the 300 to 350 range. Assuming the probe is accurate, 250 does seem low. If the tank otherwise looks good, then the absolute number is not too important. If you are really concerned about it, there is a way to calibrate the ORP probe, but it requires a special reagent called quinhydrone. The procedure is in the owners manual, and I believe also the New User Guide.

If you want to set an alarm, try just a bit below the lowest value. If you are getting too many alarms, lower it a bit more. You are mainly concerned with something out of the norm.

Todd

fishguy597
10/21/2011, 03:44 PM
thanks swearint. i have been sitting on my apex for a month and just installed it this week. the cap that holds the ph solution looked like it leaked a little bit . luckly i took a pic befor i put it in .