Septic Tank/Plumbing Troubles...

My DH and I need some advice on our septic tank/plumbing problems. We have searched the net to no avail for information pertaining to our problem. Most people seem to hire someone to deal with these problems.

Our toilets were not flushing properly and the septic tank was backing up into the downstairs bathtub. We got a snake and cleared out the blockage or so we thought. A few days later it happened again and the toilets began to flush poorly again. We then replaced the corroded section of the vent pipe and had the septic tank pumped out. We snaked the system again and it seemed to be working again. Within a few days it was worse again. Today, we got a snake again and were able to snake the system to the point where the snake came into the septic tank. The toilets seem to be working again and flowing into the septic tank well. We don't know what else to do if it happens again. We want to handle this problem ourselves.

Any advice would be greatly appreciated.

Thanks.