ocean rock

Hi all, I have an Ocean rock in my 105L 60% planted tank. Been in there for 2 months, my loach loves it, however i'm seeing a lot of debris in it. I have 2 sponge filters in the aquarium perfect parameters, but I really want to clean it. I get there's good bacteria in it, but my media and...

I've attached a photo of the kind of rock I have in my tank, would this affect the water hardness in any way? only other things I have in my tank is plants and a cave and some smooth pebbles. My water hardness is normally around 20. I've been trying to find a type of cory which will be suitable...

I am in the process of setting up a 55 gallon cichlid tank and I have recently purchased around 25kg of ocean rock and 16kg of coral sand. can anyone tell me if this will raise my ph too high? I am planning to keep lake malawi cichlids so I will need a ph of around 7.8-8.6