5.8 is good, my 30g is at 4.9 and dropping. started at 7.5 and AS plus CO2 have reduced it to 4.9 in 4-5 weeks. i dont do many water changes though (no fish or shrimp) so it really doesnt matter right now. never seen plants grow so well (eriocaulons, rotalas UG, HC etc). shrimp and even some stowaway hydras dont seem to mind at all. i will up the ph with water changes once i plan on adding fish but for now no ill effects. KH is 1. not changing water more as i want to see how low it goes and how the snails and plants react.