Ok cool thanks so where would be a good place to look for suggestions for filtration for the 125 gal
Filtration depends upon the stock you indent to keep. If it were me and I were growing out an arowana in that tank I would want the water quality to be pristine. They will not tollerate poor water conditions. I would suggest building a sump so you can add more media as needed of if you prefer the canister route a pair of FX5's, pair of FX6's or pair Eheim 2262 filters should do it if well maintained.