As always, thank you for your great suggestions. I will relocatine my powerheads to see if I can eliminate any possible dead areas or areas of poor flow in the tank. I actually do use a good protein skimmer (I should have mentioned that in the earlier email), but I will try adding a couple of airstones into the sump to add additional oxygenation. (It is my understanding that placing airstones directly into the main tank is not good for male seahorses? Do you agree?) Since this is a 30" tall tank, maybe the lower depths are not getting enough oxygenation? If so, then I hope that dropping in a couple of airstones as well as moving the powerheads will help.
The pregnant erectus is still in the 5 gallon bucket as of Monday night and still looking fine. But I am going to try to acclimate him right now (for the third time) while adding the airstones and adjusting the flow as you suggest.
Many thanks again for your quick and helpful responses! You help is most appreciated:)