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Bad Inferno
Sat May 05, 2007, 09:17 PM
I know some have been looking at ph measurement....check out the following links...I have not tried any of these...

1. http://www.vernier.com/probes/ea-bta.html

I do not know the shipping costs however at US45.00 it seems great.You would have to have some DIY "in you" to display the result as it outputs 0-5VDC. I got this link from a reef forum.
If anybody enquires about shipping to OZ I would be interested in the costs. This unit connected into a DIY PIC controlelr could control CO2

2. http://stores.ebay.com.au/monitors-direct_PH-Meters_W0QQcolZ4QQdirZ1QQfsubZ1249473QQftidZ2QQtZk m
I did purchase my ph probe from these guy's, although their costs have gone up 40%. The pH electrode has been working great for about 9 months. I got the probe with the connector and is placed inline to my canister inlet. The pH probe with display looks ok, don't know about quality. unfortunately its only for display not CO2 control.


cheers
Bad Inferno
Sat May 05, 2007, 10:10 PM
was thinking about item 1 above..the only measurement I do not make is ORP so I have asked the question on shipping myself...

These vernier unit giving out 0-5VDC and only consuming 7ma means you can fit a 1wire A/D directly into the unit and digitally monitor the values.
DIY
Sun May 06, 2007, 01:18 AM
I'm interested.

I have considered making my own PH amp several times but if the shipping is reasonable this is a much simpler way to go.

if there's a few of us maybe combined shipping could make it worthwhile?
Bad Inferno
Mon May 07, 2007, 08:38 PM
shipping is US35 for one unit and US45 for two....Bit too high for me as I actually already have two ph/orp controllers.
Bald_noggin
Wed May 16, 2007, 01:21 AM
Hmmmm, might have a think about this one for a litle while....
DIY
Wed May 16, 2007, 02:53 AM
I plan on making one soon, will let you know how it goes. It may take me a few weeks as I'll be doing it in my spare time - I plan on having the following features:

. Operate from a single supply, preferably 5v
. Have a gain of around 8.2 to provide a resolution of .01 PH using 10bit adc found on most PIC's @ 5v.
. Calibration adjustment pot's included to reduce need for memory usage on PIC due to programmed calibration routine.
. Work with 1-wire ds2450 as well as PIC, although ds2450 accuracy is only 8bit...
. Simple & cheap to build (hardest part should be making the board)