Electroplating systems and methods with increased metal ion concentrations

An electroplating method comprising:

• adding a metal-ion-containing starting solution to a catholyte to increase a metal ion concentration in the catholyte to a first metal ion concentration;
• measuring the metal ion concentration in the catholyte while metal ions electroplate onto a substrate, wherein the catholyte reaches a second metal ion concentration that is less than the first metal ion concentration;
• adding a portion of an anolyte directly to the catholyte when the catholyte reaches the second metal ion concentration, wherein the addition of the portion of the anolyte increases the metal ion concentration in the catholyte to a third metal ion concentration that is greater than the first metal ion concentration;
• measuring a catholyte pH in the catholyte;
• detecting the catholyte pH is less than 2;
• and
• adding a second portion of the anolyte directly to the catholyte upon detecting the catholyte pH is less than 2.