Hi,
Just to throw my two pence worth in...
Good call on the Synodontis, he will look really cute but muller your neons when the lights go out. Learnt that the hard way. I'd suggest using Cardinal Tetras though instead of Neons. They take the higher temperature better and personally the colouring is far more striking IMO.
I too used pool filter sand but it is a nightmare to clean easily and effectivly. Now joined the BB club! Other members on here suggested using terrascotta plant pots, which work really well and the plants will thrive. I have just really planted on my driftwood and that looks just as good.
I know I am going to get slated for this but...I do not age my water the pH is stable at 7.2 and never changes. All my pipe work is plastic and I have a gas heater so water does not sit in a boiler. All the water her is desalinised (which is just the same as passing it through a giant RO unit. Minirals are added after this process and it remains constant.
I do use a UV sterilizer (opinions on this will vary) but personally, if you get the flow rate from you canister to the unit correct then it does help. I change the bulb everey 6 months as it will start to degrade over time. I have never had any fungus/bacterial problems since using it.
Jim