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#1
10/28/2007, 09:04 AM
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ORP and water changes
I just noticed that my ORP drops by almost 100 points when I do a water change. I do not disturb the sandbed, and I use Tropic Marin salt mixed with RODI water from a Spectrapure RODI. The replacement salt water is made up 1 week ahead of time, and is well aerated for that time. The ORP drops from about 420 to about 320. WHY? I have an ETSS 900 skimmer, and do not use ozone. Any input would be greatly appreciated! The water changes are twice monthly, 15% changes on a 180 gal tank.
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#2
10/28/2007, 02:55 PM
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this is normal after water change and after heavy feeding. My drop about 50-75 point.
__________________
"Every friend that I've had, practically, has wanted to borrow money or something and of course, once they borrow money from you, you can't be friends anymore." |
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#5
10/29/2007, 09:40 AM
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I have had mine reading in the 400's before moving the ground probe closer (~4") to it.It was receiving light from the fuge that I think was affecting as well. Now it is in the mid 300's. It is a little more stable now as well.
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Don What have you got to lose? |
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#6
10/29/2007, 01:41 PM
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Thanks for your well intentioned input, but people with large downdraft skimmers often will have ORP's in the 400's with no ozone. I have a laboratory grade ORP probe that is 2 inches from the ground probe of my Aquacontroller 3 Pro. The real question concerns the dip in ORP with water changes, not the readings that I have between water changes. Thanks
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#7
10/29/2007, 03:04 PM
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Quote:
----------------------------------- Hello Everyone, I have a newly setup 240 gallon tank/350 gallon system, it is only about 3 months old. I am monitoring the ORP using the AquaController III pro ORP probe. I have noticed the ORP has been climbing slowly over the past month. The ORP is currently at 475, which based on my research is really high. I just did a 60 gallon water change last night, with RODI water mixed with Red Sea Coral Pro salt. The ORP dropped to around 320 when I added the 60 gallons to my sump, but slowly as the water mixes the ORP rises back up. I am not using any kind of ozone in the system. I am currently running a Korallin Calcium reactor with ARM media. Can you tell me why my ORP is climbing? Is this something to be concerned about? Thanks for the help I appreciate it! Jason Quote:
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#8
10/29/2007, 03:21 PM
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Water changes and ORP come up frequently as a topic. I don't remember any explanations, but the numbers you've give sound fairly normal. Maybe Boomer can help more.
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Jonathan Bertoni |
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#9
10/29/2007, 06:01 PM
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but people with large downdraft skimmers often will have ORP's in the 400's with no ozone.
Nope, it can't ge done  . Maybe in the very, very low 400's but that is about it. 420, no way.ORP probe that is 2 inches from the ground probe of my Aquacontroller 3 Pro. Maybe that 's why. Move it to 1 ' (12") There is to much decoupled voltage, sometimes called "induced voltage", going to that GP. I hope to God you have a GFCI Maybe Boomer can help more. New water is often low in O2 and there is not any heterotrophic activity (bacteria) nor does it have any biological activity or physical factors going on to raise it so the ORP is low. And if the system becomes to overloaded with bacteria and organics it does the opposite and drops. It also removes around the COD and BOD. Despite what one thinks or has been led to believe, the term "oxidation" does not mean something is reacting with O2, it means that some ion has lost an electron. If Fe+1 looses and electron and becomes Fe+2, it is oxidized and it does not make any difference how it go to that state. It may have been reacting with Oxygen and it may not have been it. |
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#10
10/30/2007, 02:03 AM
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Boomer I have to admit i am getting kind of confused here !
 If natural sea water has an ORP of 250 is it healthy using ozone to bring the ORP up to 400-475 ? or what is the healthiest level of ORP you recommend ? whats ORP in nature ? I have done a lot of reading in RC thread but I am admitting I am still confused from this subject, maybe you can throw some light on the subject
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Official 2007 FMAS electrical speaker, flashlight and tape measure giver. |
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#11
10/30/2007, 05:58 AM
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Quote:
http://reefkeeping.com/issues/2006-03/rhf/index.php
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Don What have you got to lose? |
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#12
10/30/2007, 09:19 AM
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Quote:
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#13
10/30/2007, 11:04 AM
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Atah boy Don
Agois, the ocean is around 400, it is fresh mixed seawater that is not.
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If you See Me Running You Better Catch-Up An explosion can be defined as a loud noise, accompanied by the sudden going away of things, from a place where they use to be. |
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#14
10/30/2007, 05:28 PM
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Quote:
now I am a happy man again 
__________________
Official 2007 FMAS electrical speaker, flashlight and tape measure giver. |
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#15
10/30/2007, 05:59 PM
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Ok
__________________
If you See Me Running You Better Catch-Up An explosion can be defined as a loud noise, accompanied by the sudden going away of things, from a place where they use to be. |
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#16
10/31/2007, 01:59 AM
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scooter, freshly mixed salt water generally has an ORP of around 220 mv or so.
So it is no mystery that your ORP will drop when doing a water change. The real thing to watch for is, how fast does it recover after a water change. This is what monitoring ORP is all about. How fast can your tank recover from water changes, feeding, etc. I would not target anything over 400 mv personally. My tank usually takes about 8 hours to recover from a 20% water change. I consider that pretty good. And about 4 hours after feeding.
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#17
10/31/2007, 02:42 AM
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Boomer, I hit 435ish with just my needlewheel skimmer and air being drawn in from outside. No ozone.
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"If at first, the idea is not absurd, then there is no hope for it" -Al Einstein |
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#18
10/31/2007, 11:09 AM
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Your meter is lying to you it can't get that high
Take the probe out and clean it and check with a cal solution or a Quinhydrone test.
__________________
If you See Me Running You Better Catch-Up An explosion can be defined as a loud noise, accompanied by the sudden going away of things, from a place where they use to be. |
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#19
10/31/2007, 01:06 PM
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Quote:
I have switched the same system with the same maintainance schedule and bioload to high-end NW, and my ORP is maintained at a lower level (300 - 330).
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#20
10/31/2007, 01:27 PM
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Sorry Stony I do not buy it to many variables
.I will have to see proof before my own eyes with the same system hooked up to two different skimmers and then switch them back and forth and the readings backed-up buy at least two ORP probes of Lab grade. Every time I have told someone, with these ORP's, to check their probe (cleaning and recal) and probe placement, it sure funny how those high ORP's go right back to where I said they should be in the very high 300's in a good system and a great system very low 400's "maybe".
__________________
If you See Me Running You Better Catch-Up An explosion can be defined as a loud noise, accompanied by the sudden going away of things, from a place where they use to be. |
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#21
10/31/2007, 01:48 PM
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You're in MN, when you coming down to the cities
Minnesotans are soooo skepticalIt's a new probe. I don't think it's lab grade, I got it with an AC3. I asked about calibrating it, and Neptune support indicated that they don't recommend it. I did skim the calibration process forthe AC3, there are two solutions required? Some Quinhydrone dissolved in ph7 solution, and some dissolved in pH10 solution.... I was stupid and got some lab standard 450mv solution, could I mix that with the pH solutions? I'm willing to do this... |
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#23
10/31/2007, 01:55 PM
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Ok to show my ignorance what is ORP?
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#24
10/31/2007, 02:00 PM
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My ORP doesn't drop nearly that much when I do water changes... may be 20 points.... on 20% wc.
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#25
10/31/2007, 02:20 PM
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John you have probe /meter problems....period, can't happen with out oxidizer like ozone. Take the probe out and clean it with a pH 4 cal solution and a Q-Tip. Also take some tank water out and put it plastic container and test it somewhere else in the house away from the tank and all the electronics.
Stony This is the Quinhydrone test and other ORP testing http://www.ph.co.za/orp.html http://www.sensorex.com/support/tech...orp_speed.html http://www.sensorex.com/products/orp...cessories.html and then there is this http://www.coleparmer.com/catalog/pr...u=0547860&pfx= You may want to read this it is all there ORP and the Reef Aquarium http://www.reefkeeping.com/issues/20...ture/index.php See this part ? Figure 1. pH and ORP as a function of time for 6 days in the reef aquarium of Simon Huntington.[ It was to late but I told him to check his probe and clean it and the high ORP drop way down. We have a thread on it somewhere here. Minnesotans are soooo skeptical...........when you coming down to the cities True but I played with ORP probes and some @ $ 250 each for like 35 years to include ozone and other oxidizers . I use to come down there once a month but not anymore. I use to hang-out at Alleygators. Debby, the DJ, is one of my best friends. I also know the owners quite well. |
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