The only potential problem I can see is your "dry dosing" turning to "mush dosing"
The longer it sits in there the more likely this will be a problem - one of the reasons I'm trying one of the smaller units first. I'll just have to wait and see. The unit does have an air inlet for an air pump to ventilate it but I can't quite see myself going this route.
put it near a strong current in the tank so the powder (I'm assuming you are using it to dry dose) has the best chance of dissolving fast
I'll put it right by the outlet of my filter which has a very strong current so that should cover this.
Thanks for the feedback. My biggest concern at this point is that it seems so simple yet noone seems to have done it. I'm always suspicious when something seems to easy - time will tell.