Hi all
Does nitates effect ORP readings. What would say 25mg/l increase in nitrates
have on ORP readings for the same water sample, all others things being
equal.
Best Regards
Daveb
Posted
by James P on 2/6/2007, in reply to "Nitrates & Orp readings"
Good
morning Dave,
Yes, but
not directly.
ORP reading is NET reading after all individual REDUCTIVE and OXIDATIVE
effects are taken into account. You want the 'winning influence' to be
oxidative. In one sense, you want to see your ponds oxidation levels say
" bring it on"! to the reductive reactions.
Reductive reactions vary but they tend to have a few things in common.
They burn oxygen like its going out of style and they tend to be associated
with organic decomposition of one type or another.
Nitrate is
the final byproduct of ammonia and as such, a rising level of nitrate
means one of two things- a very over active nitrification process ( usually
associated with too many fish in one pond even though the filters can
manage the ammonia output) or decomposition. OR maintenance/feeding issues.
There is
no way to answer your question about the rise in nitrate and a corresponding
drop in ORP. This is because,( and very very few hobbyists can grasp this
so listen up) ORP is not a measurement like temperature or ammomnia reading
. It is a 'moving number' that is only valuable in terms of telling of
a TREND in your water's oxidative potential. And as such, it is also a
relative number. Relative to oxygen, temperature and pH at any given moment.
Having said
that, a general statement can be made- If you have high or rising nirate
level, you will likely have low or declining ORP
The remedies
can be as simple as removing two fish, doing more water changes, slowing
feeding, increase circulation and turn over rate, adding air stones, keeping
the sump cleaner, adding a TT.
Hope this
helped? JR
Posted
by DaveB on 2/6/2007, in reply to "Re: Nitrates & Orp readings"
Thanks
JR
I think I am getting the general idea. Interestingly enough During the
summer here in the UK when the covers come off, waterfall and fractionator
go on, waterchanges go up (due to increased maintenance, lid comes of
trickle tower.The nitrates come down. Unfortunately the feeding rate goes
up. I have only recently applied a ORP meter to the system (280mv) It
will be interesting to see what it is at the hieght of the season.I may
have to consider removing a couple of koi (I will admit I am overstocked).
Unfortunately In my case increasing waterchanges only adds to the blanketweed
problem (high phosphates in source water)
Best Regards
DaveB
Posted
by James P on 2/6/2007, in reply to "Re: Nitrates & Orp readings"
It
will be interesting watching the trend. Just remember that a reading at
55 F and a pH of 7.2 will be different from a reading taken at 68 F and
a pH of 7.8 Yet the ORP readings ( lets make them up) of 270 and 310 mV
even though they are different numbers, can be exactly the same in expressing
how oxidative the water is. I mean EXACTLY the same! In fact, to illustrate
this I have created a table off of Albert Theil's table ( which came from
a German publication) that show at a fixe PH or a fixed temperature what
the corresponding ORP should be to be called 'ideal'.
Armed with
that, you can appreciate that my numbers are useless for your pond assessment
and your ponds numbers are useless on my ponds assessment.
Better to go out every other day , at the same time of day and in the
same part of the pond and collect a reading. Note the temperature and
pH as well. Then create a chart. You will then plot this graph and see
the trend line. It will amaze you how the season and feeding schedule
along with the activation of all life, from koi to microbe, mess with
the trend line.
Posted
by DaveB on 2/6/2007, in reply to "Re: Nitrates & Orp readings"
Jr
........I appreciate what you have said and so have puchased a constant
readout p.H meter. I intend to maintain this at a constant 8.0.I also
have a digital constant readout for temp.So am I correct in thinking that
if I can maintain the ORP levels at what they are now and maintain a constant
p.H then the amount of oraganics would be less.If there is a rise in temp
of 10 deg C
.......I did forget to mention that I have a bubblebead on my skimmer(Which
is where most the waterchanges are carried out) and due to only having
1 bottom drain the waste does take a while to get to the bottom drain.Due
to the above conditions I beleive that an ORP reading of 280 is the best
I will do and therfore expect it to slowly fall.
Best Regards
DaveB
Posted
by James P on 2/6/2007, in reply to "Re: Nitrates & Orp readings"
Dave,
the water temperature, unlike an aquarium setting, is a variable in the
koi pond. This is because oxygen saturation levels will be different and
diectly linked to water temperature ( warm water holding less oxygen than
cooler water).
Unlike text book chemistry, where pH is the main and most powerful variable,
a koi pond will also be HIGHLY dependent on oxygen levels. This is actually
very logical if you consider the amount of oxygen spent in chemcial reactions
carried out during mineralization for instance. Not to mention koi's use
of oxygen and the nitrifier's need/use of oxygen.
So in some
cases, 280 will be a really excellent reading and in others, an average
reading. The good news- its never a bad reading!
JR |