Continuing our series of posts on Rainwater Harvesting 101, today we will look at the importance of calming the rainwater as it enters your tank. This is a very simple step to include in your system and improve the quality of the water that you end up taking to the end use.
After pre-filtration, the rainwater entering your tank will have very small pieces of sediment that remain. These particles tend to either float to the top of the water surface or sink to the bottom of the storage tank. The ones that sink to the bottom of the tank create a biofilm, which is easiest to describe as a healthy "ecosystem" within the tank in which bad bacteria is typically consumed by the biofilm. So, this biofilm plays a big role in your water's health so it is best to keep it intact right? That is where the smoothing inlet comes into play.
By use of...
the smoothing inlet, the rainwater is directed upwards and away from the bottom of the tank as it enters
Think of a fishbowl for a moment. If you have a fishbowl with a low water level and you suddenly dump a large amount of volume into it, it will typically stir up the water and cloud up the water with whatever has settled on the bottom of the tank. This is what we want to avoid doing when the rainwater enters the storage tank. By directing the water upward and away from the floor of the tank, we are not disturbing the biofilm. This also prevents the sediment from being stirred up and floating around when your pump or hose bib is attempting to draw water out for use. This process also has the added advantage of introducing oxygen into the tank.
For most applications, we use the WISY stainless steel Smoothing Inlets (available in 4" or 8") for the ease of installation, the long-term durability of the component, and the fact that it takes up very minimal space in the tank. For smaller applications (for example: using a downspout filter), we recommend using two 90-degree elbows to make a "candy cane". Both ways are acceptable as long as you direct water up and away from the floor of the tank.
Next post: Floating Filters