Contact the guys at RK2 Systems. They work with many livestock distributors, public institutions, and private exibits. I took care of an approx. 3,000 gallon shark tank through the company I worked for for a year or two. All of our equipment was sourced and installed by them. It's not cheap but it looks like they went cheap the first time. All I can tell you is be very honest with the clients you are working with about the cost up front. The maintenance costs will far exceed the equipment costs over time and they need to understand that unless you like working for free. Let them know that they are in for a big bill and if they can't understand that I would get out now. You can't save every poor fish in poor conditions just like you can't rescue every dog in the pound. The 6am phone calls from restaurant managers with leaking tanks that you didn't install get old really quick. Sorry to be a debbiedowner but being in the business had a lot of perks and good times but ultimately ruined the hobby for me for a long time. Good luck.