Possible tank upgrade

you can order precut sheets of glass and acrylic from glasscages.com i wouldnt reccomend getting it put together by them just have cut it and then ship it but you will need a truck to pick up what you buy from them.

 

For anything under a couple hundred gallons that's not a special shape I'd recommend glass due to the reasons listed previously. There are plenty of great tank manufacturers that will custom make a glass tank for you (Deep Sea Aquatics and LeMar are a couple that are top quality).

For a budget tank you could do Glass Cages, but I only ever use their tanks for refugiums, sumps, etc. because they dont look the greatest.

If you are really set on DIY acrylic then I'd recommend finding a good local (or semi-local) plastics place. Additionally, you could have them bend it so the front corners aren't seams. Lastly, find one that's done tanks before and have them do the seams - not that more costly than the material, cut and bends and it puts the responsibility on them to make sure it looks good and doesn't leak.