I have a Antec 900 with all the fans on high will this drain the power and would it be ok to knock them down to low

Only you can answer this.
 
How are your temps looking?  If your temps are ok then of course you could.

There is no way it will drain the power on your computer. Turning the fans to high only adds about 5-10 watts each.

I have all my fans except the exhaust on medium (exhaust on high) and have my q6600 OCed to 3.5ghz. Temps are very acceptable and the noise level is still well below my former vacuum cleaner (aka athlon 2500).  
 
point being, it may not be necessary to run all your fans on high.

I have the Antec 900 with all the standard fans, and an added Thermaltake 120mm side fan. I run them all on the lowest settings and the system is very quite, while my temperatures are just fine. (E6300 overclocked to 3GHz, 8800 GTS overclocked to 600 core/2000 memory). I've run the fans on medium and high before, the system ran a little cooler, but the system went from being nice and quiet to sounding more like a jet engine!

I have the Antec 900 with stock fans except for my lapped  zalman 9700, my fans are on high.  MY CPU is the 5000 Black Box OC to 3.2 Ghz nad my temps are  @ 30 C @ idle and after 2 hours of Prime 95 temps never went over 40 C.  You shouldn't have to worry about temps.  Check thru your BIOS or Speed Fan to get an idea.