The only substrate system that I know of that contains significant amounts of macronutrients (nitrates, phosphates, and potassium) is ADA's Aquasoil/Powersand combination. It can cause issues when first set up, even with CO2
supplementation, unless frequent (twice weekly) 25-50% water changes are performed for the first two to four weeks. Green water is the most likely result if water changes are not performed, as the substrate releases healthy amounts of nitrates and phosphates, especially the Powersand. After about a month it will mediate its release of these nutrients and is a joy to work with.
I wouldn't worry too much about not having CO2
with ADA's substrates unless you also have high lighting (3+ watts per gallon). High light will cause no end of algae woes unless CO2
is supplemented. Excel may help for a while, but in my experience it is no substitute for actual CO2