Snails are not the problem, I have some, but not many. There are 15 tetras and 3 bristlenose. The tank was running about 10 years before I changed the substrate. That was about 4 months ago now. I am going to try turning the co2 up as exv152 suggested. I have a drop checker but I could never get it to read correctly. I think it might be all the wood. Anyway I'll let you know if it works.
Thanks for the help.