Substrate

[danski]

i just used plain play sand from the local home depot..be sure to rinse it good and clear before putting in..i used a 5gal bucket and a little sand at a time and it was clean in no time. by little i mean i didnt just dump the whole bag in and start rinsing, maybe 1/3rd..

 

[Themuleous]

When you say very soft water what KH we taking?

If its over 2 then adding CO2 shouldn't be a problem, I use RO water and have the tank at stable 3KH and add CO2 with no problems, although it helps to do regular water changes.

 

[IceH2O]

When you say very soft water what KH we taking?

If its over 2 then adding CO2 shouldn't be a problem, I use RO water and have the tank at stable 3KH and add CO2 with no problems, although it helps to do regular water changes.

My KH is somewhere between 3 and 3.5

I decided against the onyx sand. If I feel the need to raise my KH I'll just add crushed coral to the canister filter.