Measuring Ca Reactor dkh with a Salifert test kit instructions.

[Alabamareef]

Ok I just want to clear this up. To measure the dkh from my Ca reactor using a salifert test kit are these instructions correct:

Mix 1ml Ca reactor effluent with 1 drop of KH-Ind and multiply the result by 4.

Example: my reading, in the 1ml syringe, is 0.26. This translates to a dkh of 11.5

11.5 X 4 = 46

So my Ca reactor effluent dkh is 46

 

[Alabamareef]

Bump

 

[mcarroll]

Where are you getting your instructions? Interesting method.


Not saying what you are doing is incorrect, but all you should have to do is dilute the sample you are testing until it's in-range for your test kit.

Not unlike what I've done in this thread:
https://www.reef2reef.com/forums/re...uring-do-yourself-two-part-concentration.html

I'm guessing, but simply diluting by half might be good enough for a reactor. So...

For Salifert, you normally take a 4mL sample to test your tank water for alkalinity.

To test your reactor effluent, take a 2mL sample and add 2mL of RODI to it to make a total of 4mL in your sample vial. Then test as normal to get your value in ppm, then multiply by two since you diluted by half.

-Matt

 

[Alabamareef]

Ive done that but got no color change. From what I understand if that happens you refill your syring then add the results together with your first value at 15.7, for a full syring. Then if I use another 0.48 I would add 15.7 + 8.0 = 23.7 X 2 = 47.4
So my example would be 47.4 dKH?

 

[Alabamareef]

Oh and I've been all over the internet looking for instruction for a Salifert or Red Sea kit. Even called Red Sea but not a fan of the color change on the RS Alk test kit.

 

[mcarroll]

Again, not saying what you've calculated is incorrect - I am not a chemist. All these test kits just give good approximations anyway, so I suspect there's more than one acceptable way to get at the number you want - but I would dilute the sample again vs using more reagent.

Let's assume your number is at least close and your reactor is putting out 47 dKH.

The Salifert kit is only calibrated up to 15.7 dKH, but its sweet spot where it is most accurate is around 9 dKH.

A 1 mL reactor sample diluted with 1 mL of RODI (2 mL total) gets the reactor sample down to 23.5 dKH.
A second dilution with 2 mL RODI (giving 4 mL total) would bring that to about 11.75 dKH. (Salifert says accuracy suffers a little above 11 dKH.)
I'd probably dilute it one more time (you'll use less reagent and gain a little accuracy) with 8 mL of RODI (16 mL total) that would bring dKH down to about 6.

Take your test sample from that final dilution and you should be able to get a good test using your kit's standard procedure, then multiply your test result by 8 [=((X * 2) * 2) * 2] to account for three dilutions.

Hope this makes sense!

-Matt