Salifert test question

[Mikenroe]

Need help with recognizing what color to stop at. I recently bought the Salifert test. However the alk instructions say to stop when the color changes to red/orange or pink, whichever comes first. When I use the check solution and follow the procedure of testing, stopping when I've reached what the bottle says the dkh is for the bottle. I see a purple color at 6.7 where as if I go to what they say the color should be. I get 7.3. Same with my water. I tested and when I see the same color as it was for the checker solution at 6.7 I get 7.8 where as if I go to what they say the color should be. I get 8.3. I have no clue to what the color should be. Can anyone explain it to me. I wish there was a digital reader that is accurate.

 

[Ron Reefman]

You are asking a lot of an aquarium test kit. Buy a different brand kit and you will get a different reading. Close to the same, but different. Even kits by the same manufacturer will give different readings. Our club did a group test where we all were using the same water and the results were all over the place. Most where grouped around a central point, but some where off the mark more than I'd like to believe. Was that the test kit's fault or the operator? Good question.

Exact numbers from your tank are less important than stability in whatever the number is. People run tanks with alk from 6.5dKH to 11.0dKH. Stability is the key issue.

 

[Fish Keeper82]

I wish there was a digital reader that is accurate.

You could try a Hanna checker that's a digital readout. I use red sea alk pro test kit. I like it better than the Salifert. Red sea has instructional videos that help out.

 

[thegrun]

If you are stopping at the first sign of color change you need to add more regent (usually one more drop will give you a complete color change to the proper color and test reading result). You should expect a variance with home test kits of somewhere between 5% and 10%.

 

[reefgeezer]

To calibrate you eye, try a test and keep adding reagent until the color no longer changes. That is the color you are looking for.

 

[MrZoa]

kh salifert one point more

 

[vegaskid11]

I get a more pronounced color change (and more accuracy) when using half the standard measurements of each part of the test. It's in the instructions how to do this. Basically, half the water, half the dye and double the reading you get on the chart. This method will generally give you a slight change at one drop before and then a very noticeable shift on that last drop. Works great for me.

 

[Mikenroe]

All great answers, thank you! However does anyone no if the color should be a red/orange or pink for the Salifert? Or is it more purplish. If I keep adding the reagent drop by drop there is a point where it will change to that orang/red or pink color but that's usually about after I a add 5 more ppm of the reagent. I know stability is key but isn't the right parameters. If I add x amount of buffer to raise kh thinking my levels are lower and now I have add to much. Or are these all I relative and I should just trust when the color changes and stay with same testing strategy every time I test. Maybe I'm being paranoid, but I've never tried to really keep levels really stable before as I only had LPS, Softies, and NPS corals. Now I'm getting and adding SPS corals. Thanks again for any advice.

 

[Dan_P]

All great answers, thank you! However does anyone no if the color should be a red/orange or pink for the Salifert? Or is it more purplish. If I keep adding the reagent drop by drop there is a point where it will change to that orang/red or pink color but that's usually about after I a add 5 more ppm of the reagent. I know stability is key but isn't the right parameters. If I add x amount of buffer to raise kh thinking my levels are lower and now I have add to much. Or are these all I relative and I should just trust when the color changes and stay with same testing strategy every time I test. Maybe I'm being paranoid, but I've never tried to really keep levels really stable before as I only had LPS, Softies, and NPS corals. Now I'm getting and adding SPS corals. Thanks again for any advice.

I would call the color pink/red at the end point. There is a definite purple/violet color just before it changes over to the reddish color. The intermediate purplish color can last a few drops. It can be subtle.

Your pursuit of accurracy is great, and yes, you are being a tiny bit paranoid. If the level of accurracy you are trying to achieve was needed to keep SPS, there would not be a reef hobby.

 

[Mark426]

I have used Salifert for years to measure all my parameters (Hannna for PO4). I choose to keep my tank at 8.5 dKH. When using the kit, I keep adding until the color changes to a pinkish orange (no hint of purple). Thats when I call the test done. I can run the test 5 times and be within .2-.3 every time. So, is my tank truly at 8.0, 8.5 or 9.0? Who knows and it really doesn't matter as long as you're not at the extreme ends of acceptable parameters. Just use the same color indicator every time. Stability....right?
Mark

edit: Once in a every 20-30 tests I will get a result that is way off. Retest and its right where I expected. I have yet to figure out what causes this. Not worried about it.

 

[billdogg]

I have used Salifert for years to measure all my parameters (Hannna for PO4). I choose to keep my tank at 8.5 dKH. When using the kit, I keep adding until the color changes to a pinkish orange (no hint of purple). Thats when I call the test done. I can run the test 5 times and be within .2-.3 every time. So, is my tank truly at 8.0, 8.5 or 9.0? Who knows and it really doesn't matter as long as you're not at the extreme ends of acceptable parameters. Just use the same color indicator every time. Stability....right?
Mark

edit: Once in a every 20-30 tests I will get a result that is way off. Retest and its right where I expected. I have yet to figure out what causes this. Not worried about it.

That is exactly how I do it as well (- the Hanna checker) The actual number is nowhere near as important as the repeatability of the test as long as you are someplace in the "acceptable" range.