Reef crystals at $59 a 200 gal box how can u go wrong onley problem I have is keeping my alk high I'm always dosing to raise.

reefers best and tunze

Assuming you meant for reef tanks?

I use H2Ocean for my reefs, and IO for my FO tanks. I voted for the H2Ocean because I think you're referring to your reef tank.

Someone once told me you're not supposed to be able to buy the boxes as those are intended for store use and have lower levels. Any truth to this? I seem to recall testing lower when I was sold a box but can't remember now.