duke33;1229164; said:
You are better off bleeding extra air with a T instead of turning the air down. Turning the air down will increase back pressure and shorten life of your rubber valves and diaphrams. This is even more important on larger volume air pumps.
yourockit said:
Yourockit - what are you trying to achive? What depth of water, are you using airstones, air wands or sponges? If airstones, what brand/size bubble? How many will you be running? How much air do you like? If you want high volume - low pressure economical air you can get some excellent diaphram pumps like `The Pump 40`. If you want really high volume you can use Blowers which are noisy and expensive to run.
If you have a fishroom I recommed a large pump on a central ring feed. (2 pumps on same line is good redundancy). Place pump above water level to stop back siphoning If its a large air pump, dont step down diameter and make sure the the ring feed doesnt have any dead ends. A decent diameter (I use 25mm on diaphrams and 40mm on blowers) will act as an air resevoir and allow delivery of equal pressure everywhere. Try to make the silicon airline coming off the ring line all the same length and as short as possible. I dont like to use airstones which need cleaning/replacement and do restrict airflow. On my deeper tanks, I put the airline only halfway down the uplifts since I get enough water movement this way.
If you want a rough guide, I would estimate half a litre/minute air per outlet for 30 cm depth. ie The Pump 40 should be able to do 80 outlets. If you only have one tank and like LOTS of air for water movement and decoration, I would get the biggest "small" airpump you can afford. Obviously, its better to have too much air than not enough.
