Coral Gravel To Sand

[bzeng21]

hi, recently aquired a tank from a mate which he tried to house a few marine fish. it has coral sand/gravel at the bottom.

recently i added some tropical fresh water fish such as tetras, guppies, bristlenose and coolie loaches into his old tank without changing the coral gravel.
the plants and fish have been in it for a month now and are quite healthy but i've heard that coral can degenerate and increase the PH which can be bad for my fishes.

just wanna confirm this, if it is harmful then i'll probably change it to normal sand.

thank u

 

[Ian H]

i know it alters the ph but dont know which way or how much!!

best bet would be to get a test kit to find out the ph of your water, you never know it may be alright!