Thanks for the reply�s. I did purchase a YSI ProSolo DO/T which is an optical unit. Bill Cody and Matt Morgan both provided some input on YSI and my research brought me to this conclusion. The Pro Solo is YSI �s latest handheld DO Meter and claims to be relatively easy to operate with quick response. I believe this to de a good decision but the cost was significant- but the benefit should help me to monitor my water quality and avoid a fish kill.
Thanks,
Al Allison