In case the pond exceeds the length and width from one model, we always advise to use a bigger model. The small models will not always cover the complete pond whereby a part of the pond will not be treated against algae. This will lead to a flow of living algal cells to the treated area of the pond thereby leading to less results with the LG Sonic® devices.
In some ponds a bigger model can also be advise to you although the ponds’ measurements lie within the range of one model. This can be a result of a high biomass of fish or plants, a high concentration of nutrients (nitrates, phosphates) or a high water flow within the water reservoir.