I was wondering if i could convert my 30 gallon into a sump for my 100 gallon.
You can use your 30 gal
for a sump. I converted one for my 210 and it worked great. I had to get some lexan from the lhs, cut it to the right dimensions and silicone it to the aquarium. The hard part was finding the pvc
bulkheads to connect the drain hose from the overflow to the sump. I've later noticed that marine stores carries and over abundance of these pvc
fittings that would work great. A 30 gal
is also a very good size to incorporate a skimmer into it, plus have room for heaters and your main pump.
How much would it cost to get a 100 gallon? $1500? Its hard finding parts for the 100 gallon on the internet.
This part you lost me on. Are you talking sump or aquarium?
Another good sorce of info on making sump and fuges out of lexan only is below. A good read to say the least.