Ion-specifc electrode array: control ALL water parameters

Thanks for the info Yogre, that's exactly what I was asking for. Being able to save the NH4 probe would probably let me leave out K too, which would simplify things some. Or, I could always leave that as an option for those who are interested.

I spent a few hours today going over papers on electrode designs and I feel very good about having adequate designs with low enough detection limits for everything but Sr. One paper last year reported good results with a 18-crown-6 ether, but there were some odd interferences. I might be able to improve it by adding a lipophilic group to the ether, but I'm really trying to avoid as much synthesis as I can. There's a dibenzo version available, but it's already used as an Sn++ ionophore. Does anyone know what the typical Sn concentration is? (might be OK if it's low enough)

Do most folks out there measure Sr, or want to?
 
Just saw your post Boomer... yeah I figured K was probably important on its own. After all there are several biological processes that rely on it (nerves don't fire without it). So it figures... So is Sr++ important or not? I know I've seen supplements for it.
 
I think its an excellent idea especially if it functions on a PHD (push here dummy) level for most of us who are not chemists. I don't really think a $1000 price point is to unreasonable, especially for those with larger systems. Heck, I have over 1/2 that amount in my controller and all I do is moniter temp/ph/salinity and turn my lights on and off.. As has been said, many people have spent $100+ on single probes, Marketing might even be enhances if it could be designed to work with one of the controllers on the market. Adding simple and already available systems like wifi to have in touch with a computer or cell phone might also be nice. Personally, I'm horrible about testing because its a PITA, and anything that does that sort of thing would peek my interest. If I could do it while sitting on the lazy boy with my laptop, even better.
 
khaosinc said:
Personally, I'm horrible about testing because its a PITA, and anything that does that sort of thing would peek my interest. If I could do it while sitting on the lazy boy with my laptop, even better.
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Well, yes that's exactly what I was trying to say. I'd like to be sitting in my big black rocker in front of my reef and be informed that I need to dose something, in which case I would probably put my beer down and do it.

Thanks khaos for distilling that for me.

Foxy, there are a LOT of us for whom weekly measurements/titrations are a PITA and we would like to be relieved from that.
 
khaosinc said:
. Adding simple and already available systems like wifi to have in touch with a computer or cell phone might also be nice. Personally, I'm horrible about testing because its a PITA, and anything that does that sort of thing would peek my interest. If I could do it while sitting on the lazy boy with my laptop, even better.
Click to expand...

Actually, that was my very first thought. I originally approached the guys at profilux (because it's already quite complete) about making a module for thier system, but they weren't that interested. I wasn't about to be daunted, so I figured I would bring it here (my original post was in the DIY section). It would be fantastic to have it do everything (lights, pumps, heaters, ATO, the whole ball of wax) and as you say, have it accessible over bluetooth/wifi but that's better saved as a separate project for a later date. I will certainly do that to my own system when I'm done.

I love the idea of saying "I wonder how my tank is doing?" and logging on to its web page to take look from 3000 miles away.
 
Does anyone know what the typical Sn concentration is? (might be OK if it's low enough)


0.00001 - 0.00005 ppm or 4.2 pmol/kg :) And most reef tanks have about 500 - 1,000 x that. In NSW it is usually in the +IV oxidation state as SnO(OH)3- or Sn(OH)<sub>4</sub><sup>0</sup> (ion-pair) .

Do most folks out there measure Sr, or want to?


Most no, but there is a test kit for it for this hobby.

So is Sr++ important or not? I know I've seen supplements for it.

IMHO people are wasting their money. But then again some just want to measure it, as they have been led to believe they need it. There is not one article on this planet that says they (corals) NEED it. However, there are animals that do. But some are going to be asking you for a Sr++ probe anyway :) Most reef tanks seem to have about normal Sr++ levels.

A short course on it.

Strontium and the Reef Aquarium
http://www.advancedaquarist.com/issues/nov2003/chem.htm
 
One more cool thing would be to data-log all of the info and have it show you graphs, so that you could look at trends. You could look for things like temp, pH or ORP changing during the day or night. You, could also have it figure out the proper amount to dose, so that you don't over- or under-shoot.

If you added data on how much you fed your tank, and have it look for trends in NO3/PO4, ORP and such you could try to predict the maximum amount you could feed your system. That's something you could do with test kits too, but it would be far from simple because bacterial and/or macroalgae growth rates would change in response and there would be a huge delays between all those. I also thought about having my skimmer cup empty into a container on a scale, and put an optical turbidity sensor in it to measure my skimmer production over time and tune it for me. I wonder if anyone has tried all that? Maybe its asking too much.

In case you haven't noticed, I tend to digress.
 
A perfectly valid concern. If it were used only as a meter to advise on dosing. If automated, it could be given safegaurds. Limit dosing amounts and such, lots of crosschecks can be built into the software. In that case, you can revert to test kits.
 
elijaher said:
One thing scarce me about high tech gear. If it fail your system crash.
Click to expand...

Low tech gear can take out your system too.

Your auto-topoff goofs up and you have a salinity crash as well as water all over your house.

Appropriate safeguards are key.
 
As a side interest, there is no way to come up with probes that can detect for example phosphate down to 0.005 ppm or copper down to say 10 ppb? Wishful thinking, I guess. :lol:
 
HighlandReefer said:
As a side interest, there is no way to come up with probes that can detect for example phosphate down to 0.005 ppm or copper down to say 10 ppb? Wishful thinking, I guess. :lol:
Click to expand...

0.005ppm is 5ppb so for both your are talking low ppb levels. As far as I've seen the answer is no, the detection limits even for the best probes are ppm level.

There are techniques that can do this (ICP-AES for example), but they cost hundreds of thousands of dollars.
 
the detection limits even for the best probes are ppm level.


But photometers go down to ~ 0.01 ppm. So, how low could a probe go ? I do not know of anybody off hand that makes a PO4 probe. In seawater the avg near the surface is .13 - 0.04 µmol/kg PO4 ---. or, 0.012 - 0.0038 ppm. It can get higher or lower depending.



Cliff

There are ISE probes that test CU++ down to 0.0006 ppm or 0.6 ppb. How well it works in seawater is another issue. High Cl-, which seawater has BIG time @ 19,000 ppm is not good at all :) High Cl- is the major interference ion.
 
Boomer said:
I do not know of anybody off hand that makes a PO4 probe. In seawater the avg near the surface is .13 - 0.04 µmol/kg PO4 ---. or, 0.012 - 0.0038 ppm. It can get higher or lower depending.
Click to expand...

Indeed, there are no commercial PO4 probes. There is a design that can do it however, even if its not commercial yet (invented last year), and measures down to 10ppb. So if your level's below this, then there is little you can do in any event at a reasonable price. The ability for this probe to get similar performance in seawater isn't known and depends on my ability to correct for Cl interference, just like the Cu probe you mentioned. In any even it can serve as a warning if your PO4 levels start getting high, which is (I think) what most folks really want out of a phosphate test, just like with nitrate.

I love it when people report 0 nitrate... no such thing, just call it undetectable.
 
I say zero nitrate all the time. :) Every number given as a test result comes with a ± range attached to it, so, as a mathematician, I see no difference between saying 10 ppm or 0 ppm. They're both ranges. :)
 
bertoni said:
I say zero nitrate all the time. :) Every number given as a test result comes with a ± range attached to it, so, as a mathematician, I see no difference between saying 10 ppm or 0 ppm. They're both ranges. :)
Click to expand...

OK now I'm really confused. As a biologist I see an enormous difference between 10 ppm and 0 ppm.

Methinks my ale-addled brain (it is father's day after all) is not seeing your jest!

Cheers!

OOOOOps just read Foxy's post again, now I understand... got to quit PUI! LOL!

Anyway... I see the point, I don't really care about the absolute value for PO4, how does my tank look?

I have no detectable PO4 right now and I'm overrun with GHA. Dosing Algaefix, and will probably post in Cliff's Algaefix thread soon.
 
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