A couple of ORP questions??

[koidud]

It sounds like I would like to purchase an ORP meter. A couple of questions . Where do I get one and what types should I look at. Also in regards to adding chemicals to pond for treatment,what numbers am I looking for with the meter. Thanks for the information so far it's been great.

[MCA]

One good source for koi pond drop kits and meters is good old AquaticEcosystems (Aquatic Eco-Systems - Aquatic Supplies for over 25 years.). Of course some dealers near you may stock them.

Personally, I like the Pinpoint meter because you can calibrate it yourself using packets of cleaning/calibration fluid. And with a retail cost of just over $100, it will not break the bank.

If you using an oxidizer such as PP to "burn" off parasites, you want to raise the ORP level to 500-550mV range for at least 4 hours. That one of the huge problems of just calculating some ppm level of PP. There is no way to know if a calculated dose got the ORP level to the right level...or was not hot enough or was too hot.

[cmungo]

Quote: Originally Posted by JasPR If you want to understand ORP do not read the internet! Several years ago I created a pond index value chart that showed in some ponds with a certain temperatures, oxygen levels and pH that a reading of 300 mV was excellent. And that in other ponds, a reading of 380mv was really needed to be the 'same' as the the 300 mV in the first pond. JR

JR,

Can you post the chart for us now?

[JasPR]

Hi, it is unfortunately three-four pages of charts! I'll see if I can get an abbreviated version up? JR

[koidud]

Hi All: Just purchased orp meter $103.00. Also ordered solution to keep probe in $12.50. Didn't get calibration solution,was told it was already calibrated. The calibration fluid is $25.00 for 1 quart.If I remember right She informed me calibration should be done about every 18 months. I well probably buy it later. Purchased from aquadic eco systems. She is sending me a cataloge and guarantees me that I well buy someting else after reading it.

[MCA]

JR's ponts about ORP has to understood in the context of ph, temp..etc. are spot on.

If all things remain the same and ph drops....ORP goes up. Why, because electrons pass more easily in acid than in base. That is why the liquid or gel in a battery is an acid...not a base.

So if all things are the same and your ORP is creaping up...your ph may be creaping down. check the ph, temp, and DO

[cmungo]

Quote: Originally Posted by MCA JR's ponts about ORP has to understood in the context of ph, temp..etc. are spot on. If all things remain the same and ph drops....ORP goes up. Why, because electrons pass more easily in acid than in base. That is why the liquid or gel in a battery is an acid...not a base. So if all things are the same and your ORP is creaping up...your ph may be creaping down. check the ph, temp, and DO

This is why JR's chart would be helpful. If your reading varied then you should check your ph, do, and temp and have something to compare it to.

I hope JR can figure out a way to condense and post it for us.

[Brutuscz]

Ok, I understand the orp being important in the context of oxygen, ph, etc.
Now a hypothetical question for JR. If I normally read 350 on my orp meter. Then see a change to say, 320. Is this a good indicator that it is time for a water change? I want to do water changes when they are neccessary...can an orp change help me know when they are due? ...and if so, what change will be considered significant? thanks again.

[JasPR]

yes, a trend downward in ORP observed at the same time of day means the oxidative potential ( oxidative 'reserve' really) of your water is dropping. Organics would be the number one reason, increased bacteria behavior and loss of oxygen would be the next. And acids building in the water and resulting alkaline reserve exhaustion/pH slipping would be the third reason.

But the real benefit of high ORP is a conformation that your system is designed well, in balance and not overstocked.
If you chart your decline in ORP with water change schedule you will get a good sense of how far you move from ideal base line readings between those water changes. The same can be done with alkaline reserve and nitrate readings. JR

[Brutuscz]

Great JR, thanks for the useful information. It gives me something new to study when the season commences.