Concentrations of 5X Tris Borate EDTA (TBE) buffer or greater may precipitate due to the nature of the product. This precipitation is a result of nucleation of salt crystals by dust particles or other insoluble materials. In some cases, we recommend heating the buffer to ~ 50°C to re-dissolve the TBE into solution. Alternately, to avoid precipitation of high concentration TBE buffers, after the solution is prepared, you can filter it through a 0.2 µm cellulose acetate or cellulose nitrate filter. These treatments have no deleterious effect on the buffering properties of TBE.