help with turbos

[gharner]

ok. i have 5 hermits, and had 3 turbos in my tank. two of the turbos died. i dont know why. i saw a worm from my live rock eating one of the dead snails. the third is doing great. my cycle is finished and i just did a 35% water change after removing the snails.
water parims:
ammonia- 0
nitrite- 0
nitrate-20ppm
PH- 7.8 ( i believe that it is low because of the large water change, it normally stabalizes pretty quickly)
my hermits are doing great and seem fine. when the snails died they kindof shrivled up and went into their shells. please help me fix this problem.... i dont know why they died.
ps. the third turbo isnt eating too well.

 

[payton 350]

it took me about 6 months before my turbo has lived...sometimes hit or miss with them....what are your calcium levels?....also turbos like cooler water....in the 70s...and ph is low....need all levels to be correct and stable

 

[gharner]

i never tested calcium. how do i raise the ph? i heard that baking soda works? my temp is consistantly 76-68 degrees.