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No error, of course, Davy. You talk about qualities, I mean quantities, and only quantities include errors in measurement. 😉
I think we talk at cross-purposes in this topic, let’s drop it.
[quote=”Davy” post=3305]After kati ani water is charged by carbon dioxide.[/quote]Sure, but which situation is clarified by this circumstance? Have you read the postings before? If so you’re responding nonsense.
I quote only this statement, because it seems too difficult to quote multiple statements:
[quote=”Stefanie” post=3154][…] How can this be if “it violates some electrochemical laws”?[/quote]
It generally is an error of measurement, not passing a criticism on someone. I’ve calibrated dozens of pH-meters several times, and if you ever find two ore more pH-meters which show the same values of a water solution though carefully calibrated before I will congratulate you.
One pH-step increases the acid concentration to the power of ten, this is significant especially at lower pH-values. If your measured values do not conform, it’s an error of measurement.I’ve appended a more detailed view of pH and corresponding EC, if youe measure a lower value of EC at a given pH, your given equipment, either the pH-meter or the conductometer, went wrong.
[quote=”David” post=3149][…] manage to have very low pH around 2.72- 3 with conductivity like 12 to 20 µS/cm.[/quote]Never ever, I’m sorry! It’ not possible to gain very low conductivity at very low pH, this would violate some electrochemical laws. I think your analyzers went wrong.
Try to measure the output of an cation exchanger; its pH will be very low, about 2.7 or lower, depending on the used tapwaters cation concentration, and its EC will skyrocket to 500 µS/cm and much more. This is because the acid ions H3O+ have their part in conductivity, the higher the concentration, the higher the conductivity.
I measured different humins in an oversaturated concentration and compared the data to a pure H3O+-curve which is caculable from electrochemical laws (named DHO here, blue curve).
A probe, which differs from the pure curve, contributes to conductivity in addition.
[quote=”bartian” post=3147]Increase in conductivity isn’t directly a bad thing[/quote]Of course, but this is a summary parameter and nobody knows in detail, which components are causing the boost. I’m not sure whether the increase is a higher NaCl-concentration or a cumulation of “bad things”.
I would neither use walnut shells nor catappa nor oak leaf because these plants increase the electrical conductivity more than the “old” tips to lower pH like peat or alder.
I cannot measure tannins but pH and EC. Walnut a.s.o. can reduce pH to 5, peat and alder to 3.5 without boosting the EC.
On the other hand leaf is looking very nice, a difficult decision… 🙂
[quote=”helene” post=2079]Right now I dont have any questions, except how do you really get the glass clean enough 🙂 ??? [/quote]Your flashlight will show your success of cleaning the glasses. 🙂
A very interesting method to take photos is placing the flashlight onto the cover glass. You have to trigger the flash using a kind of flashlight commander. I’ve tried the SU 800 Speedlight Commander with Speedlight SB 600 on my Nikon DX-40 with standard lens and Marumi Close-up +4, manually setting up aperture a.s.o.
These breeding males of P. ornaticauda are lightenend from above:
All those filtering products to sterilize water using UV-LEds are marketing gags trying to soothe the aquarists consciences, I think. Nevertheless an interesting idea, so I tried to figure out something about killing bacteria with Diodes.
First of all, UV is not equal UV. Only UV with wavelength lower than 300 nm is able to destroy bacterial DNA. The second point is: those (innovative) deep UV-LEDs are still under development, very expensive and hardly commercially available.
One of the leading manufacturers of UVC-LEDs, Crystal IS, announces its industrial manufactured use in 2015, specifically for sterilization applications in healthcare, of course. Until this point in time low-cost deep UV-LEDs will keep an exorbitant price, please take a look at the list of links. I gulped as I discovered the prize of my favorite LED (265 nm, 1 mW): 288 € (384 US$), not soldered, of course. :cheer:
The AquaEL Sterilizer UV-C AS-3W (three watts?) is on sale for 25 €, less than 10 % of a 1 mW LEDs’ prize; I consider it improbable that this application includes a UVC-LED with an wavelength below 300 nm as required.List of sources (partially in German)
- Wasserentkeimung mit UV: Potenziale von LEDs
http://www.optence.de/veranstaltungen/datein-zu-veranstaltungen/events/optence-veranstaltungen/vortraege-uv-led/wasserentkeimung_heraeus.pdf - Crystal IS Datasheet
http://www.cisuvc.com/content/datasheets/files/Crystal_IS-TO-39_datasheet-DS02-20130703w.pdf - Crystal IS claims record performance from UV-C LEDs
http://ledsmagazine.com/news/10/3/19 - Roithner Lasertechnik PRICE LIST 01/2013
http://www.roithner-laser.com/pricelist.pdf - Strahlungsquellen der Zukunft: AlGaN UV-LEDs
https://www.fh-muenster.de/fb1/downloads/personal/juestel/juestel/AlGaN______UV-LEDs_MatthiasMueller_.pdf - Photobiologie und Magnetobiologie, 2 (Photokilling und UV-Schäden)
http://www.uni-marburg.de/fb17/fachgebiete/pflanzenphysio/lehre/vmgraviphotomagneto/vl2 - Abwasserdesinfektion durch UV-Bestrahlung
http://www.mb.hs-wismar.de/~pfeiffer/Pfeiffer2003/Lehrmaterial_Vorlesungsscripte/Sonstiges/UVdesS.pdf
Water changes depend on evaporation, plant and algae growth. Measuring a conductivity of about 50 µS/cm or more brings me to start my ion exchanger, too.
Sometimes this means filling up the tank with demineralized water twice a month, sometimes however changing water up to 30% and cleaning the tank at the same time is necessary.However I prefer to let the tanks alone as long as possible.
- Wasserentkeimung mit UV: Potenziale von LEDs
