I was not
lecturing, I was merely pointing out that taking your own opinion on sand over what is needed for your fish is silly.
We all start some where, and always get it wrong to start with, that what started me on the getting more tanks as I over stocked and over stocked
I also tried to give you some further background knowledge on the fish, which yes is lecturing but in the manner of teaching you something.
Its fine to say "they need sand or mud", but knowing why they need it is always much better, as when you tell someone it should be sand and they "why?" you have a full answer, rather than "Just because!"
As for LFS a large number give VERY bad advice, but I know a few near me that do give good advice, as long as you ask the right people in the store.
Ive seen and heard a lot of bad advice in the past, even down to a staff member telling a customer it was fine to keep guppies with a figure of eight puffer in fresh water!?
And there have been many times when Ive told the customer what they had just been told was wrong, sometimes to even be told myself "What do you know? this guy works here!" so yeah its a losing battle most the time with getting the right information.
If I upset you I am sorry I dont mean to cause offense, but saying you wouldnt have sand because you dont like it really, in my opinion, is silly
the welfare of the fish is the first concern.
But as we can see you have decided to add sand
having patches of sand is ok, but it will be hard to make it look nice as well as keeping the fish happy too, it would be far simpler and easier for you to exchange the gravel for sand totally. Also remember to thoroughly wash your sand before adding it to your tank, as the sediments in the sand can brake your filters and also cloud the water, if you dont prep the sand properly.