Low ORP (below 150) means more filtration is necessary, optimal ORP (300-400) is good for skin quality and 'glow'. One can also tell if one has too much or too little PP in a system by measuring ORP -- high ORP (500+) bad in that case and below 420 means that PP is somewhat deactivated if not completely deactivated.
Growth rates are related to ORP, as are healthy fish. Once the ORP is halfway decent (220+), only a meter will tell you if a change (additional filtration or air, activated carbon, different feeding patterns, more or less KH/clay/whatever) really is doing much.
In the absense of other factors, ORP is usually inversely proportional to temperature... just like oxygen concentration.
Now that your pinpoint ORP meter has reached the end of it's lifespan,
have you decided on what the new one will be? Do all ORP meters need to
be recalibrated regularly and/or need to be placed in solution for a long
period of time before having a usable reading?
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Graham (somewhat sceptical)
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Growth rates are related to ORP, as are healthy fish. Once the ORP
is halfway decent (200+), only a meter will tell you if a change (additional
filtration or air, activated carbon, different feeding patterns, more or
less KH/clay/whatever) really is doing much.
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Roddy Conrad on ORP
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You can look at your pond at ORP values below 240 and guess the ORP
range. If you have no UV lights, but clear water, then the ORP range is
190 or above. If you have clear water but lots of stringy algae, your ORP
reading is in the 190 to 240 range, usually. At least in the zones 5 to
7 climate in the summer months! If you have no green water algae or stringy
algae, then you will need an ORP meter to tell if something you do is improving
the water. Pretty much like Jason summarized, good job, Jason! You read
and understand quickly.
A good ORP meter does a fabulous job helping to decide quickly whether some pond managament practice is helping the water quality.
A pond can have non-detectable ammonia and nitrites, pH in the good range, and have lousy water quality that is bad for fish health. Measuring the ORP of the water picks that up, and allows assessment of improvements.
So ORP meters go way beyond normal test kits in assessing pond water quality just as some folks have been saying for many years here and there. For example the British veternarian, in the article I linked in the Water Gardening thread, does an excellent job of writing it up. And many others, of course. Griff in North Carolina has been using the technology for a while to help others figure out how to fix their ponds.
So please don't say Conrad invented this or that here, I am just using
the wonderful advances others have made to help me move ahead in this interesting
hobby to provide our wet pets an optimum environment.
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Water change after PP or not
When a pond is treated effectively with PP, the ORP reading of the
water is increased to the 400 to 500 range, higher if you overdose for
the actual situation.
Higher ORP readings reflect better water quality, meaning an ideal reading is in the 250 to 400 range, the higher in that range, the healthier the water and the fish. Anywhere in that range prevents both green water algae and stringy algae of all types. See the ORP thread in the pond specifications forum for more information on that subject.
Tap water is poorer in quality than pond water that has been effectively treated with PP. The ORP readings of tap water runs in the 200 to 250 range usually, especially after chlorine removal.
So a water change after PP treatment just makes the water quality poorer by dropping the ORP reading.
While on that subject, I quit using hydrogen peroxide to reverse the residual PP level about 8 months ago. The problem with the peroxide is that it drops the ORP reading to around 200, while adding sodium thiosulfate only reacts with the active form of PP to drop the ORP reading to the perfect level achieved by the that chemistry, namely around a 390 to 410 reading. So I have also dropped peroxide addition in favor of sodium thiosulfate reversal for the same reason as not wanting to make any water changes - namely to maximize the oxidation potential of the water in the absence of strong chemical oxidizers. Meaning after the active PP is reversed by sodium thiosulfate addition. The brown color is removed by my filter system in less than 4 hours anyway, probably the activated carbon is very useful in that process.
There is no concern for the spent form of the PP. After all, koi pellet food manufacturers formulate mananese salts into the food at around 50 PPM to help the biological processes of the koi, and to stimulate koi growth. Several studies on mananese salts added to the water concluded that optimum carp growth occurs at a 100 PPM level, well beyond any level that would be achieved with the various spent forms of PP. So no water change is needed to get rid of spent PP, after all, it is simply a needed trace mineral for the required koi biological processes.
-----*** IMPORTANT NOTES ON INTERESTING PROTOCOL ***-----
Graham, you are probably right that it would take a bunch of small PP doses to clean up all the stuff in the gravel of an Aquascapes pond. And I certainly think that is worth doing at least both fall and spring, but it is a personal decision as all imply. The point of this reply is to explain one way to do that job without any danger to the fish population.
Let me describe a practice that could make even an Aquascapes pond a continual joy, without the normal yearly cleanup problems. This practice is based on the continuous measurement of water quality through ORP meters, and a continual chemical cleanup of the pond with PP powder, with no danger to either the fish or the biofilter.
For the folks who have not read about ORP meters, you may want to separately read the ORP thread in the pond specifications forum, and the links there to a long thread about controlling pond water quality with ORP meters on the water gardening forum discussion board. The basic thing to keep in mind that the ORP reading is a direct measure of pond water pollution. ORP readings below 150 suggest very poor water quality, ORP readings around 180 to 200 reflect a fairly normal pond, readings in the 200 to 250 range indicated good water quality, readings in the 250 to 400 range indicate superb water quality, readings above 420 are achieved only by adding strong oxidants such as PP or ozone, readings in the 450 to 550 range reflect a desired level of active PP to kill parasites, readings above 550 reflect PP overcharges which will kill pond fish if that level is maintained for over two hours. The link to the previous Koivet discussion is:
http://www.koivetforums.com/forums/...=&threadid=1668
The link to "several days" previous discussion of ORP meters and PP dosing on the water gardening board is:
http://watergardening.infopop.net/3...7276#6792927276
I keep my ponds at ORP readings in the 280 to 400 range. To increase the ORP reading from 280 to 410 only takes a 0.25 PPM PP dose in my outdoor koi pond to wipe out any DOC or settled solids. I have done that experiment about 50 times now, and have zeroed in on the dose for my pond to be quite exact. I have a continous ORP reading from an on line ORP meter, which I keep calibrated, on the pond. When the reading drops to 280, I drop in 6 grams of PP powder without bypassing the filter, or any of those complications. That drives the ORP reading within a few minutes to the 410 MV level (+/- 20 MV) dependably. A day later the ORP reading has dropped to 310, another 12 hours later, it is down to about 280. So I just drop in another 6 grams PP powder at the waterfall outlet, where there is really good mixing, to drive it back to the desired 400 level. The ORP meter is within 12 inches of the waterfall, and the 5000 gallon pond system is turned over completely through the filter system every 25 minutes. The reading stabilizes at the 400-420 MV level in about 20 minutes in one complete pond turnover in that particular pond.
Since an ORP reading of 410 is the approximate maximum reading without any remaining live PP in solution, this can safely go through the filter system without destroying the beneficial biofiltation bacteria biofilm. So this practice allows me to run very high ORP readings continuously, without any of the usual complications of PP use. No reversal is needed, the water does not turn brown from a 0.25 PPM dose, the activated carbon in the filter system will remove any active PP within 20 minutes if I make a mistake and give a slight overcharge.
It works for me, it will not work for everyone. It is a practice which keeps a healthy green algae growth on the pond walls, but with sparkling clear water, no crud in the system, no worry about anything "going anerobic" from crud buildup in either the pond or the filter system.
A few of my good ponder friends here and there are trying the practice out in their ponds, but this is the first time I have chosen to describe this new PP practice of mine in a public forum anywhere. I have been discussing it for a few months privately here and there.
The first few times this is attempted, it usually takes around 1 to 2 PPM to drive ORP to the 400 level found in a completely clean pond, and it may take considerably more than 1 to 2 PPM charge to achieve the desired ORP reading in a pond which is comparatively dirty, or with a gravel bottom. By the 4th day (or more!) of the practice, the dose amount should drop to the 0.1 PPM to 0.3 PPM level to drive ORP from the 250 to 280 range to the 350 to 430 range. I actually add 6 grams of PP powder to a 5000 gallon heavily stocked koi pond system about every 1.5 days. That is slightly less than one level teaspoon of the powder. So my dose rate is about 1 gram of PP powder per 1000 gallons every one to two days.
I do use higher levels of PP dose, measured live and on line with ORP meters, if I am trying to kill parasites. Then I stop the flow to the biofilter, drop in just enough PP powder to hit the 480 to 530 ORP range, let it stay at that level for two to three hours, reverse with sodium thiosulfate to an ORP reading of 390 to 420, then valve filtration back in for routine ponding. The activated carbon takes out the brown stain from spent PP in about two hours, so I don't need the peroxide trick. The water always crystal clear, no brown tint, the colors of the koi "jump out at you". They sparkle in the sunlight, my eyes dance to the tune they are playing....I respond to the simple joys of this life with Lizzie and out various pets (koi, goldfish, golden orfes, three talking parrots, two Bouvier des Flanders dogs, various tropical fish aquariums, some lovely, spirited grandchildren, some adult children we actually enjoy....)
Incidentally, with the cleanliness I maintain with the routine 0.25 PPM PP treatment to keep ORP in the 280 to 410 range, getting the ORP reading to the 480 to 530 range to kill parasites takes only about a 1 to 1.5 PPM PP dose in the same pond water maintained so clean. This must be what the British do when they use a 1.5 PPM PP dose to kill parasites in their comparatively clean koi ponds of high end British hobbyists. If they allowed their ponds to get to the level of filthy water an average USA ponder maintains, certainly a 1.5 PPM dose ain't gonna kill no parasite populations......
I like this technology because it eliminates the real dangers of overdosing with PP in the rare case where a ponder drops in that recommended 4 PPM dose to kill parasites and clean water to find they kill a significant percentage of their fish from a PP overdose. I have talked in private to a large collection of individuals who have killed fish with carefully measured 4 PPM charges to carefully measured pond water volumes in the repeat PP dosing practice of every day or every few days to kill out a parasite population. This is a dangerous practice in my opinion. Adding PP to a known level of active PP through the use of ORP meters to measure the PP dose live is a much safer practice. I am certainly not the first one or the only one to use ORP meters in this manner, but it is not a subject that has been explained in words the average ponder can understand. Whether I achieved a satisfactory explanation in these few short words certainly remains to be seen!
Hope this little piece helps someone somewhere make a personal decision about their pond and how to manage it to optimum fish health.
This is a very controversial post, hopefully the thread can stay pleasant!
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Griff
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Why orp???
How many times have we asked our selves what can I do to make it better!!!!!???????
If you have clear water you can not really tell the difference when changes
are made.
With an ORP meter you can measure the differences that some minor changes can make . I have tweaked my system a little here and a little there and have gotten a 100 point increase in orp readings !!!!!!
Plain and simple it takes out the guess work!!!!!!
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Example of how things effect orp readings , I washed off some water
hycins and dumped into pond for the fish to feed on. ORP was in the 320
range and it droped to 85 in a few hours as the bacteria and organic stuff
was being oxidized off. It was back up the next day when the left over
plant material was removed. I did not see the same drop if water hycins
were treated with PP before putting into pond.
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Jason , The orp probe takes about 24-48 hours to settle down when it
is new. After that it takes about an hour for it to settle down after it
has been moved.THE PROBE MUST NOT DRY OUT!!! I keep mine when not in pond
in a storage soultion of one part chlorox and 3 parts water.
Also after several days in pond a week or so it needs to be cleaned . I just stick it in the storage solution over night and then back into the pond the next day.
An orp could be used for a club . The pinpoint with a scientific probe may be a better choice . I do not have any direct experience with the scientific probes.
If you ever use one that is a very good tool to have in the tool box!!!! You will not want to give it back, IMHO.
Place probe in pond as far away from water fall as possible. That will
give you the lowest reading . Work from there.
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Two weeks ago I pulled a muscle in my back and was laid you for a week.
I did not feel like doing my regular pond maintance so I tried Roddys Low
level approach of 8 grams of pp in my pond . I fed it in to pond at several
locations . ORP readings shot up to 465 . I did it again today with 6 grams
and ORP shot up to 420 range .
With my back being out I have not been able to change out the AC that is way over due , Water stayed brown for 6-8 hours. Ac got changed out today .
I am still working no this .
What I do not under stand is that I have been able to consistantly run ORP readings in the 300 range during the summer . Now with the cooler temps. Orp is droping off to the mid 200s during the week. I do have some leaves falling and one area of the system is netted to keep leaves out. I still get a few. It is amasing what a 12-24 leaves in the system will do to water quality.
Note of interest . I added 11 good size fish into my system several weeks back and the extra load droped ORP readings down to 220 range and as the TT,s kicked up with the added load in 3 days orp was back up to 300s.
Ps back is OK now . We now have his and hers heating pads. Wow how sexy!!!!!