QUOTE(bluecoat @ Apr 6 2014, 04:19 PM)
Do you means depend on how dirty of substrate to determine age of soil since you say depend on filter system ? Ur crs tank got fish ? I find worn in my tank . Thinking if got small fish can eat worm. But the fish shall not eat shrimp
Nope, if your filter system is powerful like using high powered canister filter , the soil properties will be filter out faster and depleted resulting
in buffering power depleted faster.
for example , in one of my tank , i use UGF combine with canister filter , the shrimp soil i use the buffering power only last 1yrs++,
where else another tank with UGF & sponge filter only, it last 2yrs++.
Fish, follow the rule, if shrimplet size fit the fish mouth, it will eat them. So get the smallest fish you can, like guppy/swordtail baby.