Sinking solid versus soluble pouch

Two dry formats, two different problems

A lagoon can present two quite different problems, and they are not solved in the same place. One is an accumulated blanket of settled solids sitting on the floor under six to fifteen feet of water. The other is general organic load carried through the water column, the routine influent burden a maintenance dose is meant to keep on top of. No single format addresses both well, which is why the launch line is two dry products rather than one.

The distinction is physical before it is commercial. Getting organisms to act on a bottom blanket is a delivery problem before it is a biology problem, and the format is the part of the answer that decides whether the organisms ever arrive where the material is.

Where each format ends up

A dense sinking solid is engineered to fall through the water column and release at or within the sludge interface, where an accumulated bottom blanket actually sits. Because only a solid reaches the benthic layer, this is the format for a standing sludge problem. In the SediLogic line that product is SediLogic Core, a dense sinking solid.

A dry water-soluble pouch does the opposite. It dissolves at or near the surface and distributes through the water column much as a liquid would, so it suits maintenance dosing and general organic load in a lagoon whose mixing is adequate to carry organisms down. In the SediLogic line that product is SediLogic Maintain, a dry water-soluble pouch.

Why the formats are not interchangeable

The substitution fails in both directions. A soluble pouch applied over a deep sludge blanket releases its organisms where the water is, not where the material is, and much of the benefit disperses before it can settle. A sinking solid dropped into a lagoon whose problem is really water-column load puts organisms at the floor when the load to be worked on is up in the water. Matching the format to the location of the material is most of the decision, and no amount of concentration compensates for putting organisms in the wrong place.

It is worth being precise about what a sinking solid achieves, because it is easy to oversell. Even a dense solid delivers organisms to the sludge interface rather than driving them deep into a dense anaerobic blanket. Reaching the interface is the realistic target, and penetration of the blanket itself remains an unsolved problem for every format on the market. That is a reason to size and place a solid carefully, not a reason to prefer a pouch that would not reach the interface at all.

Choosing against the specific lagoon

Which format a given lagoon needs is decided against that lagoon, not from a web page. Where the material sits, how deep it sits, and whether the cell is mixed well enough to move organisms down all bear on the choice. So does the rarer case in which a solid cannot be dosed at all, which is the narrow role reserved for SediLogic Liquid; like a pouch, a liquid distributes through the water column rather than reaching a blanket. That selection is what a dosing plan is for: it characterises the lagoon and the duty and hands the sizing to a person before anything ships. No format is right in the abstract, and there is deliberately no dose or price quoted here.