50 gal or 45 Hex?

I'm looking to add a new tank to my 20gal long and spec tank..
I really like those Hex tanks any opinions thanks , also it will be a Discus only Tank.
Should I buy new or used ?
I live right down the rd from the largest Fish store I ever seen , Fishy Business Fl.
I purchased 2 neons and a guppy to start my 20long on 7/5/16 " Petsmart"
Today the guppy was belly up fat dead .
Been out of the hobby for 20 years so I need tips guys help .
Feel like the people at Petco r stupid and don't give a .
i

 

I don't have much experience with discus but I would get the 50 gallon so that you have more room for more fish. Also, I would check your parameters to make sure none of them were off. I would personally get a new tank unless you personally know the person with the used tank and know what has been in it and what condition it is in. Did you a new guppy? Also, I have had many bad experiences with the people who work at pet stores so I mainly don't listen to them.

 

dimensions of the tank? I'd probably opt for whatever is longer.

 

You should get at least 6 neons because they're schooling fish

 

Hello and welcome.
Since you are doing a fish in cycle, I would suggest that you use Tetra Safe Start+(TSS+) and Prime to help cycle and condition the water. Neons are one fish I would never use to cycle a tank, they are not hardy enough to endure a cycle.
If I were you, my main focus would be to concentrate on the cycle. I think the Discus would appreciate the 50 gallon, if you can go up to a 75, that would be better. Make sure that you have the API Master Test Kit, about 27$ on Amazon, a lot cheaper than the local fish store (lfs).

 

By the way, nice looking tank, and really really like the gravel mix that you got going on...love the color.

 

Thanks for the tips

 

Aqueon QuietFlow 55 runs 24 hrs per day , 20 gal long with live plants.
I was in the Hobby 25 years ago and had the Tank, so I decided to start it up .
I've got 7 Neon Tetras and want to a a few more community fish .
I love all the tips and comments here so any help is better than none.
And the Pet-smart Aquarium workers are hit and miss with knowledge .
aren't smart at all