how long for crushed coral to start buffering?

[Mystix212]

why

In the standard tank (You dont fit this category), crushed coral as a substrate will make the pH higher without taking up room in the filtration system. This means more room for media.

 

[the_deeb]

It is not a good idea to use distilled water in your tank. By definition, distilled water has essentially no kH.

Thanks for the info. I'm actually not using distilled water. It turns out that my tap water unfortunately has a KH of 0. I think the main reason my pH has dropped recently is because I removed my W/D filter. The lack of surface agitation has resulted in more dissolved CO2 for my plants (which was the goal) but has consequently caused a drop in pH. Adding a bubbler would defeat the goal of increasing CO2.

Mystix - I agree that using crushed coral as a substrate would allow me to add a lot more, but it wouldn't work at all with my aquascape. I'm currently using black Estes sand.

The crushed coral comes in pretty small grains so I've used it to fill in all the gaps between my biomax in my filters, so it's not really taking up room. Plus, doesn't crushed coral have a pretty high surface area? It seems that it would make pretty good biomedia by itself.