The STS made by companies is working but is less efficient than if you did your own mix , with your own mix you can have your own concentration in the bottle and not the lightest one.
That said , I have seen growers using it with success .
Colloidal silver works but if less efficient than STS , to be honnest I've seen many fails using colloidal silver and no fail using HOME-MADE STS
The STS recipe is available on the 420 magasine forum or website