Cosmetics Formulation Development

I'm sorry to ask. We make a toner using the following formula. 8% 5% 2% 3% 1% 2% Zinc 1% Mild preservative 1% The rest is water. % after all mixing use normal But when left There was quite a lot of precipitation at the bottom of the bottle. Must be shaken to dissolve every time. and sometimes these sediments cause a ball up on the surface 1. Should we add other solvents or not? to solve the precipitation problem 2. This precipitation Does this result in less active skin exposure? 3. Should I increase the blending time when mixing the formula? Because we tried it and it's still settling. How should I fix it? 4. Is there any substance in the formula that is difficult to dissolve? I've used more active substances before. but dissolves well Thank you in advance for the answer.

Hello, the zinc used is or not? It's probably because the pH of the formula is too high (probably higher than 7) from using high at 8%, the solution is simple, lower the pH below 6 it will solve the problem is a sediment, the pH can be adjusted soft like 1-3%