ULM does not necessarily equate to bare bones inexpensive equipment. I think having tanks with different levels of cost associated with the setup would be good. Carbon dosing or biopellets coupled with ozone on a reactor can maintain a very nice system with low maintenance. Depending on the corals kept kalk in the ATO may be able to maintain levels or adding a couple of dosing pumps to automate 2-part dosing works well. Matching the bio-load to the export mechanisms present will be important.