Conductivity meter as a evaporated water replenisher controller

In theory, water level in the main tank is stable when sump is used.
But if something block the overflow (some slug, anemone, etc) water
level will rise and automatic RO replenisher based on a float will
add some RO water lowering salnity below desired value...
This makes float systems unreliable - or I am missing something here.

The other kind of evaporated water replenishin control is conductivity
meter which monitors salnity by calculating resistance between electrodes.
How reliable are these meters in a long term? How are they built and
what is their required maintenance? Is there a risk of false readings
similar to false reading of the float based system?

The trick it to protect your drain line from the display tank so that can never
happen. Teeth on the overflow box will restrict access to anything large enough
to cause problems. Screen works as well, the plastic mesh as is used to block
leaves from getting trapped in the rain gutters.

That being said, my beautiful Banana Wrasse somehow found a way all the way down
into my refugium two weeks ago, which left me slack jawed. I did catch it very
easily (again amazed) and return him gently to the main tank. He acted
absolutely perfect on the ride up to the tank, and simply grazed about at peace
as if it was nothing. Maybe he was just super full of food and extremely
content. <grin>

Marc


Pszemol wrote:

> In theory, water level in the main tank is stable when sump is used.
> But if something block the overflow (some slug, anemone, etc) water
> level will rise and automatic RO replenisher based on a float will
> add some RO water lowering salnity below desired value...
> This makes float systems unreliable - or I am missing something here.
>
> The other kind of evaporated water replenishin control is conductivity
> meter which monitors salnity by calculating resistance between electrodes.
> How reliable are these meters in a long term? How are they built and
> what is their required maintenance? Is there a risk of false readings
> similar to false reading of the float based system?

--
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Rather than me explain go here;


http://www.coleparmer.com/techinfo/t...tivity% 5Ffaq
%2Ehtm&Title=Conductivity
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"Pszemol" <> wrote in message news:...
: In theory, water level in the main tank is stable when sump is used.
: But if something block the overflow (some slug, anemone, etc) water
: level will rise and automatic RO replenisher based on a float will
: add some RO water lowering salnity below desired value...
: This makes float systems unreliable - or I am missing something here.
:
: The other kind of evaporated water replenishin control is conductivity
: meter which monitors salnity by calculating resistance between electrodes.
: How reliable are these meters in a long term? How are they built and
: what is their required maintenance? Is there a risk of false readings
: similar to false reading of the float based system?

Thanks Boomer, this is good link - I will try to comprehend
what is written )

"Boomer" <wcwing_nospam_@chartermi.net> wrote in message news:...
> Rather than me explain go here;
>
>
> http://www.coleparmer.com/techinfo/t...e=Conductivity
> --
> Boomer
>
> Want to talk chemistry ? The Reef Chemistry Forum
> http://www.reefcentral.com/vbulletin/index.php
>
> Want to See More ?
> Please Join Our Growing Membership
> www.coralrealm.com
>
> If You See Me Running You Better Catch-Up
> "Pszemol" <> wrote in message news:...
> : In theory, water level in the main tank is stable when sump is used.
> : But if something block the overflow (some slug, anemone, etc) water
> : level will rise and automatic RO replenisher based on a float will
> : add some RO water lowering salnity below desired value...
> : This makes float systems unreliable - or I am missing something here.
> :
> : The other kind of evaporated water replenishin control is conductivity
> : meter which monitors salnity by calculating resistance between electrodes.
> : How reliable are these meters in a long term? How are they built and
> : what is their required maintenance? Is there a risk of false readings
> : similar to false reading of the float based system?
>
>

hi.
Boomer give you a good link about some of the concept in the field. I just
want to make a couple comments.

Hobbyist conductivity monitor is not cheap. Just the probe itself can run
into hundreds of dollars. The monitor is around $500 and up. This is only
hobbyist gears. For professional gadget, you will be paying more. It is
much cheaper for a simple float switch.

When properly protected, there is very little probability that a monitor
will go wrong. Things like air bubble (or improperly seated
electrode/probe) and foreigh object is the main cause of the monitor error
and failure. Most of these are microprocessor controlled, so they are very
reliable.

The accuracy and resolution of the monitor must be good enough for the
saltwater application. I guess you just have to pick the right monitor, and
weight the cost and see if it is what you want to do instead monitoring the
water level.

bye -ck-

and lets add some more Chief.

The unit must be able to measure at least 60,000 uS or 60 mS, as NSW is 53, 000us/53mS
and it must have auto temp correction. Such toys are a few hundred dollars USA. The link I
gave is a good place to buy one and the cheapest one their page is about $400, for just a
hand held, not a controller. A controller is another issue and the cheapest one is around
$500 w/ probe on their website.

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"Chief Ephor" <> wrote in message
news:...
: hi.
: Boomer give you a good link about some of the concept in the field. I just
: want to make a couple comments.
:
: Hobbyist conductivity monitor is not cheap. Just the probe itself can run
: into hundreds of dollars. The monitor is around $500 and up. This is only
: hobbyist gears. For professional gadget, you will be paying more. It is
: much cheaper for a simple float switch.
:
: When properly protected, there is very little probability that a monitor
: will go wrong. Things like air bubble (or improperly seated
: electrode/probe) and foreigh object is the main cause of the monitor error
: and failure. Most of these are microprocessor controlled, so they are very
: reliable.
:
: The accuracy and resolution of the monitor must be good enough for the
: saltwater application. I guess you just have to pick the right monitor, and
: weight the cost and see if it is what you want to do instead monitoring the
: water level.
:
: bye -ck-
:
:

I guess a float has to be good enough in that case )))))

Have you seen float level sensors with analog reading for sale?
Not only one level on/off, but analog something like in
the a car fuel tank... the sensor controlling the fuel gauge.

With that kind of device you could build a controller which
will have a way to see the speed of water level going down/up.
So with some inteligence built in it can detect water changes
or water flow restricted by the anemone/slug...
Compared to steady evaporation, water level drop in such
"emergency" will be much faster and easy to detect.

"Boomer" <wcwing_nospam_@chartermi.net> wrote in message news:...
> and lets add some more Chief.
>
> The unit must be able to measure at least 60,000 uS or 60 mS, as NSW is 53, 000us/53mS
> and it must have auto temp correction. Such toys are a few hundred dollars USA. The link I
> gave is a good place to buy one and the cheapest one their page is about $400, for just a
> hand held, not a controller. A controller is another issue and the cheapest one is around
> $500 w/ probe on their website.
>
> --
> Boomer
>
> Want to talk chemistry ? The Reef Chemistry Forum
> http://www.reefcentral.com/vbulletin/index.php
>
> Want to See More ?
> Please Join Our Growing Membership
> www.coralrealm.com
>
> If You See Me Running You Better Catch-Up
> "Chief Ephor" <> wrote in message
> news:...
> : hi.
> : Boomer give you a good link about some of the concept in the field. I just
> : want to make a couple comments.
> :
> : Hobbyist conductivity monitor is not cheap. Just the probe itself can run
> : into hundreds of dollars. The monitor is around $500 and up. This is only
> : hobbyist gears. For professional gadget, you will be paying more. It is
> : much cheaper for a simple float switch.
> :
> : When properly protected, there is very little probability that a monitor
> : will go wrong. Things like air bubble (or improperly seated
> : electrode/probe) and foreigh object is the main cause of the monitor error
> : and failure. Most of these are microprocessor controlled, so they are very
> : reliable.
> :
> : The accuracy and resolution of the monitor must be good enough for the
> : saltwater application. I guess you just have to pick the right monitor, and
> : weight the cost and see if it is what you want to do instead monitoring the
> : water level.
> :
> : bye -ck-
> :
> :
>
>

hi.
Hey, Boomer, I send you a message on RC, and you never replied... what's up?


I never see anything that Pszemol has in mind. There are some electronic
water level controller that have a latch logic build-in, but that is not
comparable to the level of "intelligence" that you expected. Almost all
controller that I see only work in the simple test logic (on when water
level is below this, off when it is below that...). Anything more
complicated (e.g., involve PLC or microprocessor) will jack up the price by
a couple hundred. Furthermore, do you really need to keep the history of
the water level? Unless you are using a buck-surge device, most of the time
the water level is pretty much monotonic...
bye -ck-

"Chief Ephor" <> wrote in message news:...
> I never see anything that Pszemol has in mind. There are some electronic
> water level controller that have a latch logic build-in, but that is not
> comparable to the level of "intelligence" that you expected. Almost all
> controller that I see only work in the simple test logic (on when water
> level is below this, off when it is below that...). Anything more
> complicated (e.g., involve PLC or microprocessor) will jack up the price by
> a couple hundred. Furthermore, do you really need to keep the history of
> the water level? Unless you are using a buck-surge device, most of the time
> the water level is pretty much monotonic...

I was thinking about keeping the history for decision making like
"start pouring DI water if the water level dropped too quickly?".
This would make the system smarter and allow distinguish evaporation
from a water change or other things like leaks etc.
The price does not matter so much - you have similar devices for
CO2/pH monitoring and they have some circuitry to prevent emergency
dosing when pH probe fails or something similar happens.

Chief, I most surely did reply and just deleted the return-reply the other day

--
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"Chief Ephor" <> wrote in message
news:...
: hi.
: Hey, Boomer, I send you a message on RC, and you never replied... what's up?
:
:
: I never see anything that Pszemol has in mind. There are some electronic
: water level controller that have a latch logic build-in, but that is not
: comparable to the level of "intelligence" that you expected. Almost all
: controller that I see only work in the simple test logic (on when water
: level is below this, off when it is below that...). Anything more
: complicated (e.g., involve PLC or microprocessor) will jack up the price by
: a couple hundred. Furthermore, do you really need to keep the history of
: the water level? Unless you are using a buck-surge device, most of the time
: the water level is pretty much monotonic...
: bye -ck-
:
: