Ask The Engineer About Gutter Guards And Cisterns
It makes sense to choose a rain gutter cover that will clarify the rain water and exclude the highest percent of tree debris. There are several basic types of gutter guards and gutter covers. However, if there is substantial tree debris, there's only one design that makes sense.
You can also check various best gutter protectors online.
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First let's rule out basic gutter screens-they simply admit too much debris into the gutter. Try them out if you like but the problem is that you'll have a lot of gunk to clean from the cistern-it's not worth the risk since you've already spent thousands of dollars having the cistern installed.
Then there's the fine mesh they claim made from surgical stainless steel that lets practically nothing into the gutter. Yes they will keep your gutters as clean as possible and in turn your cistern will stay clean.
However, you'll want to consider that debris will accumulate on top of the mesh and not be visible from the ground. Things will be fine for a year or two until the debris literally collects in sufficient quantity to form a barrier to the water getting through the mesh.
This means someone has to clean off the top of the mesh and that may not be easy if you take a moment to ask:
1. How can you tell where is the debris collecting?
2. How are you going to remove the debris from the ground with a brush?
3. How do you know if you've removed a sufficient amount of debris to allow the water to get through the screen.