Although DGT is a registered Trademark there are unscrupulous companies which flout this and sell unlicensed products under the DGT name. Rather than using our well tested polyacrylamide gels made using a special crosslinker only available from DGT Research, they use agarose, even for multivalent cations and anions, including trace metals. It is well established that agarose gel is charged. In freshwaters, this causes DGT measurements of cations to be overestimated and of anions to be underestimated (see FAQ).