Many things are going to play a part in your decision , how deep is the mix ? , how much airflow do you need?, did you want to stay at 12-24v or bump to 110v-240v ect , are you going to run timers , how loud does it need to be (urban), how much are you willing to spend ?
Without knowing the above, but having done similar , i might be able to suggest a few thoughts ......
a) a mid-high volume air pump that i have used are in the nebulizer's for asthmatics, these have to be mounted well or they can be loud
b) their are many battery operated air pumps for fish in esky's or transport tanks for live fish like
Link
c) Foam markers on spray rigs also use a decent pressure 12v air pump
also in the effort of keeping costs down ..... do you really need a battery? , or could running directly off solar while light shines be sufficient time for aeration ?
would mean a lot less cost inputs not needing timers , battery monitors and charge controllers , would only need a regulator.. with the exception of a) as i have only seen 110v-240v models
if any of the above options are to pricey , have you considered a paddle wheel aerator like they use in fish farms ? cheap , reliable and easily obtainable .... just food for thought