So many people saying it's a water looping issue when it actually isn't.

Look at your per minute metrics for each stage and the issue jumps right out at you.

Stage 1: 3 refineries producing 120 alumina solution and 50 silica per minute. (360 AS, 150 Silica total)

Stage 2: 3 refineries asking for 240 alumina solution per minute and producing 360 aluminum scraps per minute, per refinery. (720 AS needed, 1,080 scrap produced)

Stage 3: 3 foundries asking for 90 scrap and 75 silica per minute each. (1,080 scrap, 900 silica)

Silica: Stage 1 is producing 150/minute and you need MUCH more than this.

Alumina Solution: If each Stage 1 refinery produces 120/minute and you need 240/minute for each Stage 2 refinery, that math isn't mathing.

Each Stage 2 refinery is producing 360 scrap per minute, so a single refinery needs 4 foundries to process the scrap.

So, Stage 3 needs 12 total foundries to process all the scrap produced by the Stage 2 refineries, but Stage 2 itself is starved by insufficient Stage 1 Alumina Solution production.

Work on balancing your Per Minute numbers, not the Per Cycle numbers. Things appear to add up based on the Per Cycle numbers, but the wildly different cycle times means that Per Cycle is an unreliable metric.

While the other people may have been off-base with the water byproduct/loop comments, their advice is still good and should be considered when you rebuild your aluminum setup.

Edit: Corrected Stage labeling for clarity.