Accuracy in ORP Controllers...

[mikeguerrero]

I just got off the phone with Milwaukee and learned that the their ORP Controller is +/- 5 ml in accuracy. On there webpage it says +/- 1 ml which is incorrect.

I also called marinedepot and spoke to one of there technicians and learned that both the American Pinpoint Controller and The RedSea Aquazone are +/- 1 ml.

I wanted to pick up the 50 mg Sanders ozonizer and match it up with the Milwaukee controller because you would still be cheaper than the RedSea all in one unit, $288 vs $319.

The American pinpoint is too expensive, cost $189 vs milwaukee controller only $99.

Should I worry about +/- 5 ml??? Does +/- 1 ml really make the difference???

Can anyone on this board chime in and give some opinions???

Marinedepot says RedSea ozonizers are great, that they have always carried them.

Sanders need no introduction they are German made and have a high track record.

thanks,

Mike G

p.s
I currently own the SMS 122 PH controller from Milwaukee and it works great; not to mention the customer service at Milwaukee was excellent, he answered all my questions.

[sfsuphysics]

I think that's +/- mV not ml. But I don't think there'd be much of a difference being as you're working in the range of 300-400 mV being accurate down to 1mV really would not make that much of a difference. But that being said, I would go with a cheaper unit that has more capacity if you already have a controller and are concerned about price, many have had great success with the Enaly units (about $100 shipped 200mg capacity)

[mikeguerrero]

SFsuphysics,

Thanks for replying, I was beginning to believe no one here has an ORP controller or really doesn't like the word Ozone.

Yes I meant to type Millivolt and not ML. The Milwaukee is much cheaper and it does go all the way to 600 ORP whereas the other controllers only read up to 500.

But having said that, I couldn't see any controller ever wanting to read above 500 ORP, that would be disaster in the reef wouldn't it?

thanks,

Mike G

[BobB]

Mikeguerrero: IMHO most of the inaccuracy comes from the probe not the meter. Probes can be inappropriately calibrated or fouled with slime, both of which lead to misleading readings. To address your question: + or - 5 mv when measuring in the 400 mv range is ca. 1% inaccuracy, which ain't too bad all things considered. I wouldn't worry about it, but once buying an ORP meter and probe, would be cautious about maintain a clean probe.

Good luck,

Bob

[easttn]

Originally posted by BobB
Mikeguerrero: IMHO most of the inaccuracy comes from the probe not the meter. Probes can be inappropriately calibrated or fouled with slime, both of which lead to misleading readings. To address your question: + or - 5 mv when measuring in the 400 mv range is ca. 1% inaccuracy, which ain't too bad all things considered. I wouldn't worry about it, but once buying an ORP meter and probe, would be cautious about maintain a clean probe.

Good luck,

Bob

Amen Bob. The probes are the weak link. The controller will only follow what the probe tells it to do, and the calibration of the probe drifts much more than a pH prober over the same time period. I'had one running for over two years and it is a piece of equipment that is alway suspect. Its a Red Sea 200mV unit. On the good side the meter stopped working after 8 months and RS replaced it no questions asked. Good customer service.

[mikeguerrero]

Bob and easttn,

I greatly appreciate you guys chimming in and giving your view on +/- MV.

I've made my decision to purchase the Milwaukee ORP controller for it's price, slight deviation that doesn't make the difference from 1 to 5 millivolts.

But most important is how they treated me customer service, that is, when I called to inquire.

After I was done talking about the ORP controller, I began speaking about my PH probe and how I had trouble calibrating it, he offered me a new probe if a simple calibration method at home doesn't work.

To those that followed this short thread; +/- in accuracy of just 1 to 5 doesn't constitute one being better than the other.

Just that you get a good probe or a probe that can be replaced when it goes bad.

The milwaukee probe will be connected to a Sander ozone at 50 mg/hr.

I just need to see what place has the best prices on these two units, anyone want to guide me to their favorite online LFS?

Thanks,

Mike G