The Planted Tank Forum - View Single Post - KH Standard / How to
View Single Post
post #14 of (permalink) Old 08-27-2010, 08:41 PM
Planted Tank Enthusiast
KevinC's Avatar
PTrader: (6/100%)
Join Date: May 2004
Location: Oshkosh, WI
Posts: 738
Originally Posted by JimT View Post
Thanks for the advice.

I measured it out again. Still coming up with 5 kh. I do get the blue to be pale greenish at four drops, but it does take 5 to seal the deal and be yellow. I guess the arm and hammer is suspect? It is a new box tho, and any added moisture would give me a lesser amount to the mixture, so a lesser concentrated mixture. I checked the scale, and it has been calibrated recently. I carefully measured the water with plastic disposable eye droppers. I checked the TDS in the mixture, and it came out at 74 ppm (which I suppose would be the most accurate way to measure it). Oh, just checked my conversion chart. It should be 71.6 ppm. It is good to write things out sometime isnít it? That will be a good way to dial it inÖ

The thing is 5 kh is 89.5 ppm. So, I suspect the integrity of the API dropper test (drop size could vary). The room in my lab (not a chemistry lab) that I test in is very well lit with fluorescents, and I do it on white paper for color fidelity. The instructions say the solution should be bright yellow (not pale green). I guess I would have to calibrate my TDS know for sure, whatís going on.

Thanks again
It has to do with resolution of the test kit too. All you can say is the solution is between 4 and 5 dkH (drops) since you aren't using (or able to measure) partial drops. So if the solution is 4.3 it won't turn after 4 drops but will be yellow after 5. Doubling the volume of the test solution will give you 0.5dKH per drop so there is a little more resolution.


72g bowfront planted, CO2, 4x - T5HO, Eheim 2213 and 2217, 2 angels, pristella tetras, blue tetras, betta, albino bristlenose pleco, albino cories. Sword, vals, hygros, ludwigias, java moss and fern, anubias

2g Mac-quarium. Clown gravel, fluorescent plastic plants, and 2 guppies.
KevinC is offline  
For the best viewing experience please update your browser to Google Chrome