Sulfamate nickel plating bath problem with growths

The Sulfamate Nickel How-To Guide
by David Crotty, PhD & Robert Probert

Q. I need some advice regarding a sulfamate nickel plating bath. We are having problems with growths. Growths are visible to the eye and are sharp, irregular and appearing on our goods.
Bath parameters:
41 °C
pH 3.9-4.1
nickel concentration 62.5 g/l
boric acid concentration 38.2 g/l
bath mixing by flow
we use sodium lauryl sulfate as a wetting agent

When problems occurred, we cleaned the bath with activated carbon (overnight) and filtered it. Organic additives were then added and the bath was checked again. We then performed selective cleaning. However, we are still unable to resolve the problems. We have tried all possible solutions that we could think of (improving the cleaning of goods, replacing the PP filter cartridge, or washing the anode basket and PP bag).

The bath is used for electroplating.

Thank you in advance for your advice.