| Good Job. You hit on the most overlooked aspect of veggie filters. If you do not remove vegetative matter from the system, there is not net export of nutrients. With no net export, there is no benefit. You really need to remove vegetative matter before it dies or turns brown because, by that time, a lot of the nutrients have already been released back to the system.
If determined to use a veggie filter, I think water hyacinth is the best option because:
* water hyacinth float up off the bottom so there is minimal trapping of debris and clean-up is easier;
* they do not need a substrate;
* they are easy to remove without making a mess - just grab a double handfull and toss them on the compost pile;
* they are more efficient at scavenging nutrients than most aquatic plants;
* they may not look good in nutrient-poor water, but they still grow;
* they do best in full sun but will still grow in mostly shade.
A veggie filter does one thing that a biofilter cannot do - remove phosphate. Green water and string algae can usually grab some ammonia before it gets to the biofilter and can also utilize nitrate, but they cannot flourish without phosphate.
-steve hopkins |