ORP Controller for Sulphur Denitrator

[reef_enthusiast]

Hello,

I recently started up my Korallin S-1502 Sulphur Denitrator. I have been doing some reading up on sulphur denitrators and found that the target ORP reading should be -100mV and -250mV.

I was looking into the Milwaukee ORP Controller MIL-SMS510 and the Pinpoint ORP Controller PIN-ORPCON.

My question is if this would work? Reason I ask is I looked up the manuals on the manufacturers' websites and it seems like I can't set the thresholds to negative values. Not unless I read the manuals incorrectly.

Also, if the controller does work, would I just connect another aqualifter connected to the controller and tee off the input with a check valve? That way when the ORP falls out of the -100 to -250mV range the controller would turn on the additional aqualifter and feed more water into the reactor.

Thanks for you help...

 

[Jeremy B.]

Hi,

Unfortunately you can not set those units to negative values, so they will not work for you. I know there is a way to do this with the Milwaukee unit in regards to oxidizing the probe to make it work, however I can not guarantee how well this works.

Here is a link to the information that Milwaukee has on their website in regards to negative orp readings:

http://www.milwaukeetesters.com/pdf/cond_neg_orp_probe.pdf

 

[Jeremy B.]

Update to this....

In speaking with Lou @ American Marine (Pinpoint) we can actually do this with reversing the polarity of the connection inside the unit for the probe. Lou mentioned this is very easy to do, and for instructions to do this just give him a call directly and he can walk you through it.

 

[reef_enthusiast]

Jeremy,

Thanks for the reply. I found a post from a fellow hobbyist on njreefers on how to mod the ORP controller. His mod was done to the probe wiring itself. Here is a link to the post (look for Carlo's post which is 5th post) Carlo's Post or here is a quote from his post on modding the ORP Controller:
TIP: Most ORP monitors/controllers will not read negative ORP values. Since an ORP value is nothing more then a volts reading (mV) there is a little trick you can do. Cut the probe and rewire it backwards (+ to minus, - to plus side) or pickup a couple of BNC connectors and make a "crossover" cable (what I did). With the crossover cable everything reads backwards. Plus values will show up as ZERO (or negative) but the negative ORP reading show up as positive. Now any controller can be used. You just have to remember to think "negative values". With this logic in hand, when the ORP is reading +200 (really negative 200) you want to increase the flow a bit and when the reading is +150 (really minus 150) you want to slow the flow a bit.

I'm also on the fence now of going with a ReefKeeper Lite. I asked on the digital aquatics forums and Scott from DA said that "RKL/RKE only read and control in the positive ORP range. However that will be expanded in future updates. So it is scheduled and on the books!".

Thanks again for your time and help.

Joe

 

[Jeremy B.]

Joe,

That's exactly what Lou from American Marine explained to me. By doing some very minor wiring you can get it to read negative.

 

[reef_enthusiast]

Jeremy,

I have decided to more than likely go with a ReefKeeper Lite instead of the pinpoint.

The question I have for you is do you know how many wires are inside the sheath of the ORP probe? Since I don't have one yet, I wanted to make sure I don't mess up a brand new probe.

If I'm not mistaken there should be 2 wires and I basically have to cut them, "cross" them over, and reconnect them. Is this correct?

Thanks again for your help.

 

[Jeremy B.]

Hi,

I have never had one open, however there should only be two wires in there. If there is a third, it would be a ground that just grounds to the bnc connection on the unit.

You might contact DA on this and ask them directly before cutting into it.

Thanks,
Jeremy

 

[reef_enthusiast]

Jeremy,

Thanks for the reply. I'll post a question on the DA forum.

Thanks again.

 

[HndMafia]

hmm...time to get more equipment...I'm an equipment junkie. Thanks for the ideas guys