mv Microcomputer

[Rafty]

Hi All

I am very new to this awesome hobby. I have a 500G salt water tank plumbed to a further 500G external tanks. Within the sump there is a protein skimmer, UV steriliser and nitrogen reactor. I have an MV Computer measuring ORP which turns on the ozone pump when ORP is < 400. The issue I am having is the the MV Computer always reads above 400, typically around 430-450. This level never drops below 400 (i.e. ozone never turns on). The probe has been replaced and when measured against calibration fluid, it is spot on.

When I measure the nitrates and phosphates, they are close to 0. So the question I have is, is it possible for the ORP to be consistently above 400 without the ozone kicking? The installer said not and that the ozone should typically fire up on a daily basis.

What am I missing?

 

[bertoni]

[welcome]

ORP is a complicated topic, and I wouldn't worry much about a 430 mV reading, personally. Are the animals in the tank doing well? How long has the tank been running?

 

[Vinny Kreyling]

Not To Worry mine is up there too.

 

[Rafty]

Tank is fairly new, about 8 months. Animals look healthy only issue has been stringy algae growth. When I told installer about high ORP he said in general the ozone should run 8 hrs a day at 20% which I did until a new probe arrived. When I did this there was far less algae growth so I thought it was making a difference. Now with the new replacement probe, it is back up over 449 so ozone not running at all.

 

[bertoni]

Hmm, that's interesting. If the ozone was helping, I'd be tempted to run it again, and see how the ORP responds. Maybe some day off, that'd be an interesting experiment.I'd probably shut down the ORP if it rose higher than 470 mV or so, for now.

 

[Genetics]

What happens to the mv if you put your probe in a vinegar solution for 30 min? What happens to your ORP when you feed your tank?

 

[Rafty]

I have not tried vinegar but when I put it into the skimmer slurry it rapidly falls. When I feed I drops very slightly 450>430. Never below 400. What should it do in vinegar?


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[Rafty]

Okay so I gather the vinegar is to clean the probe.

So just to clarify this was a new probe. No mention to clean prior to use. Soaked in vinegar and the cleaned with cotton bud. After that rinsed with R0 water and the placed back in sump water. ORP slowly dropped from 430 to 330 over about 2hrs at which time I reconnected ozone.

So for now this seems to be more realist ORP measurement. Will update after a few more days of observation.

Unfortunately installed never recommend the Apex controller so I only have an aqua medic my controller with no logs.


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[bertoni]

I'd give it some time to break in. ORP probes often take a while to equilibrate with a new environment.

 

[tkeracer619]

I'd give it some time to break in. ORP probes often take a while to equilibrate with a new environment.

This.

 

[Genetics]

Usually it takes up to a week for ORP probes to settle. However, when I received mine it wasn’t until I gave it a soak in vinegar Before it fell enough to actually make sense.

 

[Rafty]

The probe was weeks old and not settling. After the vinegar cleaning two days ago, ORP now sits around 400 with ozone cycling on and off over the course of the day so seems to have sorted things out. I just hope it is not reading too low and overdosing the ozone.


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[bertoni]

Is the ozone turning on now? If so, you could leave it off for a few days to see how the ORP responds.