Most probably they are just calcium deposits from the (hard) water you used in the wash cycle when developing the negatives.

1. You can use distilled water, you can get it by using on your inserting a filtering equipment that use carbon filters and a descaling agent on your tap water. If you plan to develop regularly or simply by buying distilled water by the gallon if you only develop occasionally.
2. Using a wetting agent will help in the meantime, but be aware they don’t usually have a descaling agent, they are usually made of soap that doesn’t have the additives used in current soap formulations to artificially create bubbles.

There are no magic formulas but some common sense... many film developers have built their own rituals that make them feel better but don’t have a basis in science.

Most probably they are just calcium deposits from the (hard) water you used in the wash cycle when developing the negatives.

1. You can use distilled water, you can get it by using on your inserting a filtering equipment that use carbon filters and a descaling agent on your tap water, it will pay itself for if you plan to develop regularly, but if you simply only plan to develop occasionally you will better off buying distilled water (i.e. low mineralization drinkable water from your grocery store, the cheap one) by the gallon.
2. Using a wetting agent will help in the meantime, but be aware they don’t usually have a descaling agent, they are usually made of soap that doesn’t have the additives used in current soap formulations to artificially create bubbles. If you have a “good water source” it’ll only help to reduce the wash time... even if most of them claim to have anti static properties, if you let your film hang to dry in a place with airborne dust you will get dust on the negative no matter if you use wetting agent or not.

There are no magic formulas but some common sense... many film developers have built their own rituals that make them feel better but most of them aren’t scientifically based.