I just put other posts up today, we got frustrated 'waiting' for the pressure to even out and put the old filter back in. The pressure seems perfect now and the filter does not make a hissing noise. The filters seemed to be the same size, but the gaskets were shaped a little differently. The old was indented a little, while the new one was flush. We just moved into the house and were only told the replacements were at home depot, when we went this was the only size we saw. Could this difference cause air to flow into the pipes? Or do new filters need more time to absorb water?

Is this a GE whole house filter with an element about as big around as a grapefruit?

Hi thank you for the response... It is a whole house filter, I do not see a brand name on it. It has a blue cap and the casing is grayish platic, with glass on the inside. I think its about the size of a grapfruit. When we had it off, the new filter, which is for GE, was a little wider in diameter, but the same length and so we tried it and it seemed to fit. As soon as we turned a faucet on I could hear the air hissing through the filter. I should note that we did not lubricate the gaskets, would that have made a difference?

If it's a GE filter housing there is a small button on the top, press and hold to vent the housing