I'm a ways away but if a canister filter will work for you I have one you can have it can easily support 40 gallons, also have a small Protein skimmer that suctions to the glass inside wall of tank, I have no idea how many gallons it can support or any info about it, just know it works and in a...
the exact Qty as if you were to count them all in numerical order your last number will be how many are in the display. An for the frag tank it would be as many as you need to keep the frags happy and free of any issues so it would be as many as you can count when you can see them all...
still have I know someone looking for one like that, Pm me what you want to trade for it or what your interested in especially if its equipment related if you still have
I know I am a LIttle far out but If you have not already gotten one due to this being a youngster your trying to get into our hobby I have a 20L on stand I would be willing to let go for you and your son pm me if Petco didn't work out