Quote Originally Posted by Mr Cob View Post
quote from Sea-Lab:

No. 28 Automatic Replenisher
Manufactured by Sea-Lab
Sea-Lab Formula 28 is a mixture of naturally occurring buffer compounds that maintains natural ocean concentrations of calcium, strontium, and all 15 essential trace elements. Calcium and strontium are well recognized nutrients, but trace elements are not as well understood. They are, however, vitally necessary to marine life in the aquarium. Paradoxically, these same elements so essential to life, are also highly toxic. The trick is to tread the fine line between trace element starvation and trace element toxicity. Formula 28 is the first formula available to hobbyists and professionals that creates and maintains this fine balance. As elements are depleted from solution, Formula 28 delivers exactly equivalent amounts to replace them. Formula 28 stabilizes acid/alkaline balance (pH), and also prevents toxic ammonia buildup.

Instructions for Use:
Since Formula 28 is fully buffered, this is a constant supply of essential trace elements and no possibility of toxic overload, so dosage and application are extremely uncritical. The blocks can be placed in any location where there is a moderate current. When the blocks are mostly dissolved, add a similar number as recommended in the dosage.
I don't know exactly where this description came from but it is different than the advice you'll get if call the manufacturer directly. This is a Hiatt product (www.hdltd.com) and you can contact the owner (Snake) directly and he'll talk your ear off telling you about how to use them. The blocks are calcium chloride plus trace elements. So it won't do anything for your alkalinity and you need to do regular water changes to keep your water from getting out of whack, just as you would with any other unbalanced calcium chloride additive. Also you are supposed to protect them from any current or they will dissolve too fast. Snake always recommended people bury the small ones in the sandbed to protect them from any current. It's a good product if used correctly and a bad product if not used correctly.