Is there really a big different between test kits?

[PeterEde]

I had been using ReaSea Foundation and Multi test kits.
I started dosing Randy's ALK/Calc along with Reef Anabolics.
My daily doses for Alk and Calc were around 10-11mls per day for 8.5dKh/420ppm.

I have since purchased Hanna ALK/Calc testers and have had to drop the dosing to 4-5 mls per day. Alk at 8.5dKh and Calc still coming down, now measuring 450ppm initial Hanna measured was at 480.

So why the big drop in mls required for dosing?

 

[blaxsun]

Yes, there can be - mainly due to the user component, age (etc.) of reagents - you name it. Sometimes the coloration is hard to determine visually by us mere humans as well.