Excess foaming of nickel sulphamate

A. Yes, you probably have too much anti-pit. Probably. But you didn't mention the actual formulation, the surface tension, what you are trying to do with it, etc. Most people on their 100th attempt still use proprietary processes, rather than trying to formulate their own baths. That way they get help from a tech service person who is on their 1000th attempt :-)

A. If you are using SNAP or a similar product and are trying to use anything but mild air agitation, you will get foam. If you are using SNAP did you add the recommended amount? Did you check it with either a ring test or a stag. SNAP A/M is SNAP Air/Mechanical. This is a low foaming formulation. This requires a "stag" to check the amount of the wetting agent. A ring test will NOT work. Anti Pit is just that. You use the minimum amount that avoids pitting. This will vary from part to part. If you are using home brew, good luck. It is not worth the frustration.

A. This is your first time to plate Nickel, yes?
Nickel platers need a few priceless tools:
1. Hull Cell, over-the-side model if possible
2. "Stag" = Stalagnometer, available thru Ace Glass, you have to ask for it, its not in their catalogue.
3. Separatory Funnel. Most Ni brighteners, not all, can be extracted into M.E.K. and titrated.
4. 200X microscope to inspect the hull cells and sample coupons
5. Bend tool. Make a tool that you can bend sample coupons over different diameter dowel pins to fine tune your bath organics for deposit stress.
50-100 microinches of Sulfamate Ni should make it thru a 75 mil bend radius easy without cracking.

...and you thought it was as simple as following a data sheet?

Skilled use of these tools will get you on your way

A. Sounds like too much surfactant and the wrong type! I am not conversant with SNAP, but make sure you are using a surfactant that is compatible with your plating system. For instance, do not use a surfactant that is designed for mechanical agitation in an air agitated bath or you will disappear in a bubble bath! If you are a novice to electroplating, I would strongly suggest you get your bath from a reputable supply house who can tailor the chemistry to your needs.