Alk Swing @ Night

[JimWelsh]

Sorry to resurrect this old thread, but I've recently developed a way to do semi-continuous alkalinity monitoring of my tank, and get that data input into my Apex controller.

Here is a graph of the total alkalinity of my 210 gallon tank over two days' time. I include my Amp_3 data, too, because that shows the photoperiod of the tank. As a reminder: I currently dose RHF 2-Part Recipe #1, 110 mL each day, in 1 mL increments spread evenly over the 24 hours in each day.

Isn't the strong correlation between the photoperiod and the Alk demand interesting? Makes me want to start controlling the dosing based on the Alkalinity monitor input, which would be really easy to do, now that my Apex has real-time alkalinity data to use.

 

[fab]

how? How ?? HOW???
Please...

 

[JimWelsh]

Science! That's how! I'll be bringing a prototype to MACNA to show to interested aquarium equipment / controller manufacturers.

 

[fab]

Ain't science just wonderful!

Would you give us a peek at the level of performance of what your method offers, please, without giving up anything that you need to protect as proprietary?

What does semi-continuously mean? Is it periodic sampling?
Is there a probe in the water continuously or semi-continuously?

Is your method hands free?.
Can it be done unattended?

Are you planning on licensing your method or your technology? Is there anything we can do to help you?

 

[JimWelsh]

Would you give us a peek at the level of performance of what your method offers, please, without giving up anything that you need to protect as proprietary?

I thought that was what I just did. What else would you like to know about the performance that that chart doesn't tell you?

Are you planning on licensing your method or your technology? Is there anything we can do to help you?

I sure hope I am able to sell the IP behind this. What you can do to help is to go to your favorite aquarium equipment / controller manufacturer and demand that they negotiate with me!

 

[glb]

Using diluted limewater in my ATO has eliminated the problem of alk going too low at night. The intermittent smaller doses has done the trick.

 

[fab]

I thought that was what I just did. What else would you like to know about the performance that that chart doesn't tell you?

Touché, the chart is great! What kind of accuracy should your method provide and what kind of repeatability. How much of an integration time interval is required, if any? Does the method provide a continuous readout?

I sure hope I am able to sell the IP behind this. What you can do to help is to go to your favorite aquarium equipment / controller manufacturer and demand that they negotiate with me!

I will gladly start with a post on the Neptune Systems forum if I have your go ahead. Have you begun talks with anyone, yet?
fab

 

[GainesvilleReef]

Jim,
This is so interesting. It also means that since I test alk in the morning, I am reading the peak. The best time may be at lights out. But based on my consumption I can make a useful guess at what my swing may be.

 

[WindeyD]

I use an apex and BRS doser to spread my doses out and still there are fluctuations depending on the time of day. I would say that as long as your corals seem happy and the Alk doesn't swing too dramatically then you are probably ok; sometimes I create more problems by tinkering too much

 

[JimWelsh]

Regarding accuracy, find below the results of a recent calibration test I did. I created four aqueous standards with 2.5, 3.0, 3,5, and 4.0 meq/L alkalinity. I used the average of four tests of both the 2.5 and the 4.0 standards to adjust the slope and bias of the device, and then ran 10 replicates of each of the four standards. The numbers above and to the left of each set of data points are the mean and uncertainty (2 * SD) of that set of data points, and the numbers below and to the right are the individual values for each set of 10 controls.

Each analysis takes appx. 5 minutes to complete. The device outputs a signal that emulates a pH probe, e.g., if the result is an alkalinity of 8.12 dKH, then the device outputs a signal with the same voltage a pH probe would have if the pH was 8.12. It outputs the signal for the last test performed, until the next test is done. Tests can be scheduled from as frequently as every 5 minutes (uses a lot of reagent, though), to once an hour, once a day -- whatever the user wants.

 

[JimWelsh]

@fab, I just saw your edits above.

Yes, it is automatic and unattended. It samples periodically. It uses a single reagent, and needs access to RO/DI, and either a drain or a waste bucket/container that is emptied as needed. The sample tube stays in the tank/sump.

 

[Randy Holmes-Farley]

FWIW, this was going to be the sort of thing the Mindstream would be really good at, if it ever hits the market.

 

[JimWelsh]

FWIW, this was going to be the sort of thing the Mindstream would be really good at, if it ever hits the market.

Well, that appears to be one very big "if", and Mindstream would have no provision for interfacing with any controllers.

 

[Randy Holmes-Farley]

true.

 

[hawkinsrgk]

Way to go Jim. Hope it turns out to be a big hit

Sorry to high jack, but since you are talking to companies you may want to talk to Red Sea. Your potassium test kit mod really helps to see the endpoint a lot better

 

[fab]

Will your method, device, be extendable to other reagents and tests?

 

[JimWelsh]

Way to go Jim. Hope it turns out to be a big hit

Sorry to high jack, but since you are talking to companies you may want to talk to Red Sea. Your potassium test kit mod really helps to see the endpoint a lot better

Thank you. I'm glad you like it!

 

[JimWelsh]

Will your method, device, be extendable to other reagents and tests?

Perhaps, eventually. I've experimented with both Ca and Mg methods with this hardware, but have not developed refined, workable methods yet. I have decided to focus on alkalinity only for this incarnation.

 

[Nibejeebies]

Interesting . While I'm not at this level of reefing I'm following along... Why?...
Science!

 

[FranklinDattein]

On the topic of Alk monitor, a couple of guys in Asia developed a piece of equipment that claims to do it:
https://www.facebook.com/groups/1768033033431949/

The technique doesn't look like rocket science and I hope a more affordable and smaller versions come to market, soon.