Strange ORP readings ?

[sidewinder770]

Curt, or anyone else who might be able to help,

Below is a graph of my ORP readings. The tick marks at the bottom represent 7am each day so it's about 10 days worth of readings. I was wondering if this appears normal. You will notice the drastic upswing, which occurs each day at about 9am, which is when my 250w MH's come on. As well as the corresponding downswing at the end of the day when they shut off. Currently I don't have anything but the probes plugged in- no X10 modules yet. My question is this- is this trend normal? Do MH's typically do this? I am also noticing my ORP is steadily rising (which is good) but, it is approaching 460 this weekend (and rising) and I haven't been running Ozone for about 2-3 weeks- would ORP typically get that high without ozone?

Thanks in advance for any insight into this issue.

 

[sidewinder770]

Almost forgot- it's a ACIII PRO with PH, OPR and Temp probes which were calibrated when I got it about 3-4 weeks ago.

Thanks again

 

[scenaria]

yep.. thats very normal..

your tank and probes will settle in and fluctuate between night and day... against your PH

I think mine are highest when I wake up in the morning... (lights off)

 

[kattner]

And you will also see a rising trend over time as the probe gets dirty with a bio film. I clean mine about once every two weeks.

 

[sidewinder770]

Good to know about the cleaning intervals- I didn't think they needed to be cleaned that often.

I actually looked at it last night and apparently my ballasts were interfering with the readings- the probe wires more than the actual controller. The probe wires were about 18" from my ballasts but as soon as I moved them farther away the readings dropped 20-25 point on ORP in about 2-3 seconds and the PH dropped as well. I have read that VHO ballasts could interfere but was suprised to see that my MH ballasts did as well. I am running 2 icecap electronic ballasts just for reference. Glad I got that one figured out- I knew something had to be wrong and this morning- no spike like the graph above shows- just a steady increase/decrease which is probably the way it should be.

Thanks again.

 

[North Bay 101]

Scott, the ORP readings look fine. I see a gradual increase in ORP levels due to the probe building a film that will need to be cleaned off when the levels get above 430. The other thing to look at is the inverse relationship between pH and ORP levels. If one gets out of whack it is time to clean the ORP probe or recalibrate the pH probe.