potassium chloride

Hi reefers, I wonder if anyone can give some advice for source of Potassium Chloride for DIY additive. I recently ordered this powder from amazon (also posted screenshot in case people don't want to click on links), and it shows that it has no other ingredient other than potassium chloride, and...

So when installing new Pinpoint pH probe I didn't notice the electrode was broken and the KCl leaked into my 20g tank. I don't have access to a potassium test kit in a timely matter so I wanted to know if it would be harmful? So far all corals and 2 bta's appear fine. Any info is greatly...

Well, I finally decided to join the crowd especially since I want to grow out some nice sps pieces. After doing some reading on potassium I decided to pick up a test kit. I found Amazon had a Salifert available, so a day later it was in my mailbox. Having ran out of my Reef crystals last...