Recent content by DaveOB

Very odd that. At the time I wasn't convinced by the pool test strip so I also did a test with the liquid pool test. 5 drops of some purple-ish reagent ( I think it is called phenol red ) and it turned a mid to dark orange color which matched the bottom of the printed color chart of 7.2 pH. I...

Hi Borek The carrier solution ( CS ) was made with 200ml distilled water and 100ml hydrochloric acid. The result was about pH 7.2 In the test tube it is then 13ml of the CS, and then 0.5ml ( or more ) of the Borate Solution ( pH around 8 ). I am not able to measure the pH of the combined...

OK. I think I have some progress now. I checked the pH of the 1000ppm borate solution ( B ) with the pool test strips and it is above 8. So I made a 'carrier solution' ( CS ) of 200ml distilled water and 100ml of hydrochloric acid. The curcumin extract ( CU ) is 40ml acetone + 1...

Hi Borek I am using this : http://bildr.org/2012/01/adjd-s311_arduino/ and : http://netram.co.za/1339-5mm-triple-output-led-rgb-common-cathode.html I have a 4 x 4 electrical box with 2 pvc electrical pipe ( conduit ) in a cross shape ( intersecting ). A 15mm glass test tube fits almost...

Borek - you hit the nail on the head - the reaction I was seeing was not rosocyanine. Just watched the video on this page : video and about 60 seconds into the video, the author adds curcumin to both an acid and a base ( both with no borates ). The acid remains the yellow curcumin...

ok. the light bulb just came on -- now I think it is starting to make sense ! When I first tested, and added curcumin reagent to water with borate solution ( no castic soda ), I saw a flash of red ( assuming rosocyanine ) which disappeared within about half a second. Google told me that...

OK. I have managed to get a reaction, but the results are nowhere near what I was expecting. Background : I have a color sensor and RGB LED attached to an Arduino board and the results displayed on an LCD. The test tube is positioned between the LED and the color sensor in a light tight...

Hi Borek Thanks for the explanation - appreciated. Told you I was "New to chemistry". :) OK. So looks like my control solution and b1 and b2 dilutions ( ? ) are as I calculated ( 1000ppm, 8ppm, 40ppm respectively ) even though I should learn the correct way to get to the right answer, do you...

Hi Borek Thanks for the reply. I will try and explain my ( possibly / probably incorrect ) logic. The 'control solution' of 5000ml water, 44 g Borax power and 22ml hydrochloric acid. My thinking was that if this creates a 1000ppm solution, and I then take 1ml of that 1000ppm solution and add...

Hi all New to chemistry and needing some advice please. I am busy with a DIY project for my home pool. I have assembled an RGB LED and a color sensor to read the color of water in a test tube. Firstly I am using this to better read the color of the DPD 1 tablet color in the water that...