Esc,
Good, now can talk about important things.
Sisters live in NM, rain fall is same as MI.
Yet, they need 5,000 gal tank to make it through the 5 months with little rain.
Here in MI 2,500 gal tank is fine, maybe little smaller. Rain more consistent.
To sterilize the Rainwater UV and Ozone are the better choices.
UV bulb can fail and must be replaced each year, not a cheap bulb.
Ozone is more expensive up front, yet should work for years, as in decades.
UV draws 3x the power of Ozone, further enhancing the Ozone choice.
Ozone can be bubbled into a tank sterilizing the whole tank, not possible with UV.
Other uses for Ozone. Only needs to be on while its raining.
One big tank or many little ones?
I considered 55gal tanks, then realized how many needed 45 for 2500 gal, 90 for 5,000 gal. Realized the fittings would cost more than the one big tank! Example:
http://cgi.ebay.com/2500-Gallon-Poly-Fresh-Water-ONLY-Storage-Tank-Tanks_W0QQitemZ120313239938QQcmdZ
ViewItemQQptZBI_Farm_Supplies?_trksid=p3286.m20.l1116
$865. Do not like to put all my eggs into one basket, so will use two 2500 gal for sisters house. Also cheaper than one 5,000 gal tank? Go figure.
First flush.
Not found a device I like, either cost or design. Attempted my own design, not like them either. Have long list of requirements. Still looking/designing.
Self cleaning gutters.
Found ALL self cleaning gutters do NOT work, what a disappointment. (they can have limited success under certain conditions). Designed my own very happy with (as a design).
Hope this was helpful.
Have fun,
Scott.