[KoiCop]

Hello koibooii . . .

I think you missed Steve's point, so please let me try to rephase it.

If the existing filter is already bio-converting all the ammonia passing through it at a flow rate of X, then doubling the filter size will not bio-convert any additional ammonia -- it's already converting all of it that passes through it, and you can't convert it twice - whereas increasing the flow rate will reduce the ambient ammonia level in the pond since more ammonia will be bio-converted per hour.

If the existing UV is is already killing all the unicellular algae that passes through it at a flow rate of X, then doubling the UV's power will not kill any more algae -- it's already killing all of it that passes through it, and you can't kill it twice - whereas increasing the flow rate will reduce the ambient algae level in the pond since more algae will be getting killed per hour.

That's why Steve pointed out that increasing the flow rate will achieve both objectives at the same time -- whereas doubling the filter size &/or the UV power will gain nothing. Make sense?