I can't get hot water always or pressure, I think my water filters have something to do with it, I've gotten rid of them and I have more cold pressure, I have gravity flow, I clean the pipes out, any other suggestions

There shouldn't be any air in a gravity flow system. If you're looking for more pressure and volume why not install a booster pump? This would have your storage tank act as a well. Your installation would go from the tank to a check valve to a pump and then to a bladder tank and from there in your unit. More questions?> I'm as close as a click. Cheers, Tom