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Topic: PH fish tank (Read 1 time) previous topic - next topic

Drew Davis

Thanks for all the input!! I still have a few questions.


From what I saw it seemed like you could just leave the PH sensor in the tank for long periods of time with out attention. Is that correct? Also, if I use the wiring diagram (link below) could anybody show me how to get the value from the sensors into an integer so I could use the numbers in my program. 

http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Sensors/Biometric/Wiringdiagram.pdf

Also, this is not for fish. It's for algae.

http://www.algaelab.org


Thanks for all of your help!!!!

seanz2003

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From what I saw it seemed like you could just leave the PH sensor in the tank for long periods of time with out attention.

In very clean water, possibly, and even then the chemistry of the probe has a tendency shift over time.  The surface of the bulb needs to be clean for a good measurement. On top of that I'm guessing you'll be growing algae... In my experience, you'll find yourself cleaning it about once a month( probably more in your case) and calibrating every week or so. It depends also on what the alga's tolerances are.

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Also, this is not for fish. It's for algae.
I was gonna say, poor fisshies :(

Drew Davis

Spark fun gives you 3 bottles; 250ml Red Buffer Solution - pH 4.0, 250ml, Yellow Buffer Solution - pH 7.0, 250ml Blue Buffer Solution - pH 10.0. How long do you think that will last? Also do I just leave the sensor in the tank or do i need to extract a sample from the water and place it into the sensor.

Thanks,
Drew Davis

seanz2003

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How long do you think that will last?
I use 20-30ml in a small medicine cup, once a week, so 250ml should easily last at least 10 weeks.
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Also do I just leave the sensor in the tank or do I need to extract a sample from the water and place it into the sensor.

Have you used glass pH electrodes before (the handheld kind, possibly)? If not, I would strongly encourage you to do a google search and research them. Anything left in the tank is going to quickly acquire a nice layer of scum within a few days, therefore requiring frequent cleaning. How much the algae growth affects your reading, I couldn't tell you, maybe not at all. (In my situation, accuracy mattered greatly.) And frequent cleanings run the risk of damaging the sensitive bulb. If it were me, I would get two probes and keep one in the tank and properly store the other. When it is time to take your measurements, place the clean probe in the tank and let it stabilize for a minute, then compare the two readings.

jabbado

#9
Dec 30, 2012, 07:33 am Last Edit: Dec 30, 2012, 07:52 am by jabbado Reason: 1

Also, this is not for fish. It's for algae.

http://www.algaelab.org


Interesting link! Glad you said it was for algae as I was surprised like Delta_G with what fish you were trying to turn into caustic soup  :smiley-eek:

If you look up aquarium controllers a lot of the pH probes are damn expensive. I'm not sure if that's just because they're made to last while continually in the tank, or also because aquarium equipment is often overpriced. Some of the well-known manufacturers recommend cleaning them at least every couple of months. Many people use undiluted white vinegar or lemon juice for this. Even then the probes only last up to 18 months or so.

As for the buffer solutions, since you're only concerned with a pH of 10-11, did you know a borax solution can be used to calibrate near this range? It will produce a buffer solution of around pH 9.2, so this method requires a controller that will allow calibration using arbitrary buffers. That Sparkfun kit doesn't do that.

EDIT:
I just did some searching and apparently these probes are pretty popular for the price:
http://www.bulkreefsupply.com/brs-brand-ph-probe.html

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