With the help of Randy Holmes-Farley, I have made a 14 dKH solution of sodium hydroxide with which I can compare my alkalinity test kit results. As it happens, while attempting to keep my tanks at 10.5 dKH, at least according to the API kit that I have now, I have really been keeping them at about 12 dKH. From now on, each time that I change to a new Alkalinity test kit, I will first test a sample of the comparison solution that I have made with that new kit, and compare that result to the known alkalinity of 14 dKH, and then write that on the test kit so that I won't forget it. [smilie=sleepy.gif] Today when I tested the 14 dKH "standard", it tested about 12.3 with the API kit. That is 13.8% less than what it really was - 14.
14/12.3 = 1.<u>138</u>
(I have used API for 6 years, so have got sort of a feel for the different shades of blue that you get, and so am guesstimating the 3/10. If it is really 2/10, or 4/10, I am off by less than 1% either way, so it is not critical in my estimation. I am trying to get more accurate readings without having to become a chemist.)
Since I am shooting for 10.5 dKH, I will want a reading of about 9.2 on this test kit.
1.138x /1.138 = 10.5/1.138
x = 9.23
I purchased a 500ml bottle of sodium hydroxide 1.0N on eBay for about $25. I mixed 5ml of this solution with 995ml of fresh ro/di water that has nothing added to it - I almost used my topoff water that I always add Prime to. This solution now is a known alkalinity of 14 dKH, barring any variation in measurements. I did the best that I could with what I have. I know that I will be able to get a much more accurate reading than I have been getting! Thanks to Mr. Holmes-Farley for all of his hard work at Reef2Reef!
If anyone would like some of this, I am glad to mix up some extra. Let me know that you would like some, and come by with a clean 500ml bottle and we'll fix you up! That amount should be plenty to last for several years. I can't make this available to everyone in the club, but the first 50 can have a bottle.
Thanks for looking!
14/12.3 = 1.<u>138</u>
(I have used API for 6 years, so have got sort of a feel for the different shades of blue that you get, and so am guesstimating the 3/10. If it is really 2/10, or 4/10, I am off by less than 1% either way, so it is not critical in my estimation. I am trying to get more accurate readings without having to become a chemist.)
Since I am shooting for 10.5 dKH, I will want a reading of about 9.2 on this test kit.
1.138x /1.138 = 10.5/1.138
x = 9.23
I purchased a 500ml bottle of sodium hydroxide 1.0N on eBay for about $25. I mixed 5ml of this solution with 995ml of fresh ro/di water that has nothing added to it - I almost used my topoff water that I always add Prime to. This solution now is a known alkalinity of 14 dKH, barring any variation in measurements. I did the best that I could with what I have. I know that I will be able to get a much more accurate reading than I have been getting! Thanks to Mr. Holmes-Farley for all of his hard work at Reef2Reef!
If anyone would like some of this, I am glad to mix up some extra. Let me know that you would like some, and come by with a clean 500ml bottle and we'll fix you up! That amount should be plenty to last for several years. I can't make this available to everyone in the club, but the first 50 can have a bottle.
Thanks for looking!