Revenge of the Algae

It’s day three of the algae treatment of my pond. The data are not that encouraging if you were rooting for algaecide as a quick fix for my swampy green problem. Here are the results:

Visible spectra of pond water over 3 days

The absorption spectrum looks fairly consistent over the three days. We have had temperature fluctuations of about 10-15 degrees in addition to rain, so there are many variables that can impact subtle variations in the shape of the spectrum. The water has not altered from its turbid, green characteristics, and the spectra support the claim that little has changed in terms of algae content.

Fluorescence spectra (excitation wavelength of 405 nm) of pond water over 3 days. The spectra have been normalized by setting the height of the peak at 405 nm to 1.

The fluorescence spectra are displayed slightly differently from the previous articles in that they have been normalized. Assuming that the excitation peak stays roughly the same regardless of conditions, normalizing the spectra allows for a better comparison of the peak at 690 nm. It looks like there was a big change between days 1 and 2; however there is little change, and possibly an increase, in the peak from day 2 to day 3.

The instructions on the algaecide bottle say to repeat the treatment every 3 days until the pond has cleared. I will do one more treatment of 15 mL and if I do not see any meaningful change in the water quality, I will bite the bullet and replace the water.

Attack of the Algae Part 2

Yesterday I started an algae control protocol for my garden pond and decided to monitor the progress with spectroscopy. I’m simply measuring the absorbance and fluorescence (405 nm excitation) of the pond water using a Vernier Spectravis spectrophotometer. Here are the results, compared with yesterday’s spectra.

Fluorescence spectra (ex. 405 nm) of garden pond water following treatment of the pond with algaecide.
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Killing two problems with one spectrometer

I’ve got two problems. First, my ornamental garden pond is filled with algae. In the past, I have simply emptied it out and refilled, but I’m tired of doing that, and I also suspect there are some tadpoles growing in the pond and I’d like to let them do their thing, if possible.

Second, COVID has shut down summer research at my school, and I’m in need of a science project to keep my mind in the game. Since I work mostly with instrumentation design, I brought much of my lab home with me during the transition to on-line learning this semester. One of the instruments I brought back was a Vernier Labquest with the SpectroVis Plus spectrophotometer/fluorimeter.

With most of New York having recently entered Phase II of our return to normal – whatever normal will look like – my wife and I have been spending our stimulus checks at the local garden supply store. One of their products is an algaecide that “works fast”. That got me thinking; I don’t know “fast” means in the algaecide’s promotional language, but I need to clean up this pond and I can use the spectrometer to help me measure how fast is fast.

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Adventures in PCB milling – journey begins

This is a short post to show off my first attempt at PCB milling. I’m a member of the Chicago Innovation Exchange.   Well, I was, but now it’s no longer CIE but the Polsky Center, or maybe the Polsky Echange North, I’m not sure, but that’s what happens when someone invests $35 million in your incubator; you change your name.  The center provides me access to a pretty swanky fab lab equipped with (among other things) an X-carve CNC mill. I recently completed my training on the machine and I wanted to put my skills to the test.

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A Vernier Go!Link package for Mathematica

The Go! Link from Vernier Software & Technology (Vernier), is a USB adapter for their proprietary sensors which also provides some basic features such as a buffer, sensor auto-identification and raw voltage reading conversion. Vernier provides a software development kit which allows programmers to use Go! devices in their own systems. Since Wolfram’s Mathematica software became available on the Raspberry Pi, I have been thinking about how one can build a flexible sensor system using Vernier’s products and based on the inexpensive computer and the powerful data analysis and visualization tools of Mathematica. This project isn’t new, and my earlier attempts were highlighted on the Raspberry Pi blog and I recently announced a previous version of this software package. What I’m presenting now is a more user-friendly system that makes data collection easy through the device driver framework incorporated into Mathematica.

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