just a few basic q's from a total novice: Due to an ill fish ( possible fish TI need to redo my setup. I have read the articles on the forum....these fish were resuces and I am learning as I go

Tank size: 6' x 3.5' x 1.5 ' how many gallons is this?

Substrate: I think I will use a medium sized quartz the recommended amount seems to vary from 1 -3 inches what is appropriate?

Filtration: I don't think I can pull off the reverse flow ug, and I currntly have the basic hang in type with carbon filter cartridges a double and a single-waste size is a problem so if I remove the strainer baskets at the bottom of the tubes will these still work? There has been a lot of discussion about canister type with bio beads- do I need to upgrade?

I calculate your tank to be around 230 US gallons which certainly is a nice size.

Substrate really is a matter of personal choice. One to 2 inches seems okay. Just remember that going quite deep with gravel may mean waste gets trapped deep down so you will have to be used to gravel vac to its full when cleaning. Make sure you push the vac right into the gravel to remove all that deep dirt.

They don't sell this type of filters here in the UK, however, from the hob filters that I have read about, your tank could be quite unfiltered if you just use those. I would strongly advise you to use canister filters on a tank that size.Maybe you could tell us exactly what filters you have installed

on any tank over 200 gallons i beleive one or two canister filters and a sump would be what you need to properly filter your tank.

fluval and eheim make arguably the best in canister filters and sumps are rather easy to make and install.