Breden. how did you go looking at tanks, find anything that you liked look at putting a divider in, I get my big tank next week, as soon as it arrives i wil post pics to show everyone what i mean
When/If you get a canister filter get one with a decent flow rate
With the amount of waste they produce I am looking at one that pumps at 1850lts per hour and that is for a 160lt tank. A 1500lph would do the job but my turts (murray short neck) like to swim against the current. Also the filter has an ajustable flow rate and 6 stage filtration. All this for only $189.
I used to have an ehiem but the flow rate was really weak and not worth being used with turts. The fish tank now uses it
Why not as a cheaper more affordible method get your turtles say an aquaculture tub? you can get quite large ones! also it would be quite easy to turn say a 60L plastic container into one big filter using biolballs and a bit of plumbing stuff.
a turtle tank is pretty much the same as a fish tank filtration wise and uses the same sortof bactieral setup. you just need to make sure that the amount of bacterial filtration you have is sufficient to process all the turtle waste from poo->Ammonia->Nitrite->Nitrate.
also a 3ft tank would be tini for a turtle that gets nearly 1ft in diameter! also not sure if espansa is still on aps very often but espansa breeds the maquarie turtles that max out at like 23cm.