Well, nobody jumped on that question.

DKNY suggested using the ultima and UV on a skimmer circuit. Good suggestion, mating the filtering capabilities of the Ultima with a skimmer circuit's water and waste.

MCA suggested bumping up as close to 5000g as you can, providing a good amount of water and space without causing a need to double up equipment cost. More wisdom. Poor wife has to see with a longer vision. Took my wife almost 30 years. Good luck. MCA is right, right, right.

I hope you may have had enough experience with the Ultima to think that an open system would be a good way to filter water. You could use a settlement chamber (or some other simple mechanical filter) and then one or two of several different options after it...aerated mats, fluid beds, showers. These can be DIY as you learn about them (and find deals).

If you get the pond built with adequate depth to keep the water stable and the fish safe you can leave the bottom drain unused as you save up more dough to add filtration to its circuit, running the pond on skimmer and Ultima as you do now. Just get the size, get the bottom drain and the rest will follow soon enough.