I think roger hit it on the head with you burning through filters faster and increasing the overall cost. Water in tampa area is dirt cheap so if you are worried about water cost I am a little worried lol. But from a science perspective, reclaimed water may have less chlorine in it and thus may not burn through your carbon block as fast, which could save money as sediment filters are cheap. However, if the organics are a higher level than your carbon block might have the same exhaustion. To be honest the few cents or maybe dollars you save is not worth it unless your tank is pretty large.