There is no need to change all of your tanks to dirt as it does have some draw backs at first. The 5 gallon is fine with ecocomplete it looks great! The smaller tank you could try dirt with a sand cap. Talk to OFL if you are serious about it. She also has a thread for her 55 gallon NPT. But yes, PM her and ask her on how to start an NPT and all that.
No worries. I wont change the current 5g but will read up on NPTs in greater depth. I'll most likely take your advice about setting up the 1.5, probably put some shrimp in there after I move the Doctor out into a bigger tank. Thanks again!