# Forum Home Renovation Water Saving Garden Ideas  Has anyone installed one of these?

## gsouth

http://www.silvanh2o.com.au/products...hp?category=11 
The frogmouth filter.
The concept is that it only need one connection to the water tank to provide both the inlet and the overflow. 
I have installed mine however I am getting quite a bit of water still flowing to the stormwater - I estimate this at about 20%..... Looking inside the filter it's not apparent where the water is coming from..... 
Cheers
G

----------


## Danny

For legal reasons, l will not comment directly on the Frogmouth but offer the following:
Downpipe *internal* mesh filtering systems are either one of two types; *1*. Mesh filter(s) across the total flow path to stormwater. The debris is then: (*a*) diverted to the ground or (*b*) held in a capture chamber for later removal. As most filters lose at least 10% of the water yield to self clean and transfer debris, a lot of water can be diverted to the ground by (*a*).  *2*. A deflecting mesh system that is not across the total flow path to stormwater whereby water flows through the mesh but debris is able to be diverted to stormwater. Again, water is sacrificed to self clean the mesh and transfer debris. 
The Frogmouth is a type 2 system.
A 10% water loss has long been considered the optimum for self cleaning filters but is rarely achieved and manufacturers rarely state yield efficiency. One  previously widely available product did claim a 30% yield on some literature but the claim was never printed on the product packaging to the best of my knowledge. 
An overseas diverter called *Rainthief* claims a 90% yield and diverts debris to stormwater while the hi-tech Australian *Supadiverta* claims 97+%. This is achieved by a scavenge system for the filter flush.
The University of Warwick has a good article on rainwater harvesting which includes various downpipe filter types and expected yield; if you google; University of Warwick  DRWH Technology-Filters and separators, you should bring it up. 
Varying designs impact on efficiency and the Supadiverta website gives interesting researched filter design details. 
It is strongly arguable that verified yield claims should be mandatory with these devices.

----------

