Why is it necessary to filter lime water?
The limewater is filtered so that the undissolved particles of calcium hydroxide do not make the limewater solution cloudy even before it is used to test for carbon dioxide gas. By filtering it, the limewater solution is made clear and colorless, which makes it easier to notice it becoming cloudier when carbon dioxide gas is bubbled through it.
Do you need to use the Keurig water filters in your Keurig coffee maker if your water is already filtered?
Why would you have sediment at the bottom of your pool even after you run your DE filter and use Bacqaucil?
No it's not a bad thing, as long as the filter is not too strong. If the filter is too strong it could make it difficult for the fish to swim around. It is also not usually necessary to use a filter with a betta, as long as the water is changed about once weekly. A filter would probably lengthen this time, but would NOT eliminate it.