Betty,
You really need to circulate when adding chemicals. I can't help any more on the DE filter issue because I have sand and no experience with DE filters. I'm kind of surprised there isn't a 'bypass' or 'recirculate' position on the valve. An option for circulating without filtering would be to go the the 'waste' mode and dump the waste line back into the pool if you can do that. Don't know if you have hard plumbing on the waste line that would prevent you from doing this.
Al

BTW...consider building an ARK.