Reef Crystals Alakalinity

[jcook54]

I've been having some issues with low alkalinity lately and finally decided to test my salt, Reef Crystals. The alkalinity came in at 5.4 dKH! Since I'm usually quick to suggest a settling issue when other's have low alkalinity in their fresh saltwater I decided to try another bag. So I took 8 cups out of a single bag and the alkalinity came in at 7.0 dKH. I thought maybe there was an issue with the Salifert test kit so I tested both of my tanks and they came back in the acceptable range. So, has anyone had issues with Reef Crystals producing low alkalinity saltwater? The first thing I did was google it and there are all kinds of threads about how RC has high alkalinity and there are one or two that complain about it testing "low" when it's coming in at 9.0 dKH. What gives? Did I literally get a bad batch (from 2 separate bags)?

 

[AquariumSchmo]

For the first bag, did you use the whole thing at once, or just a few cups? I have heard of situations with salt mixes where some of the elements settle at the bottom. If you didn't already, try stirring or shaking the dry salt before taking some out to make saltwater.

Edit: Just re-read your post and noticed you already thought about settling.

 

[Adam]

Two bags from the same box or even several boxes on the same pallet are from the same batch and should have the same lot number. I can't remember if IO puts lot numbers on their boxes though.

 

[jcook54]

Two bags from the same box or even several boxes on the same pallet are from the same batch and should have the same lot number. I can't remember if IO puts lot numbers on their boxes though.

It doesn't look like they do although I could be missing something. I've reached out to their customer service to report the issue and hopefully they'll have me send them a sample. I've saved the salt I was using and am going to try another bag from the same box. I'm assuming results will be the same but maybe it is just some weird settling issue.