Hello Viktor, I only had time to skip through the last video. The corrugated pipe is not fit for purpose ? I would be worried about leaves, dead animals, etc creating blockages in that flat blue hose or do you have pre filters?
The corrugated black rib hose floats so one use I have is to use short segments as free floating caves for sub dominant fish. You can increase stocking levels with more use of the water column while still keeping the tanks easy to clean.
Why don't use use a clean tarpaulin on the roof if you want to keep collected rainwater clean? Put the high end of tarpaulin over the central roof cap and weigh everything down with bags of sand. You can remove the tarpaulin for storage if you have long dry seasons. Just a thought, seems criminal to waste perfectly good rainwater while you pay for RO membranes and pumps.
Looking forward to the next video update(s).
Tarp a section of your roof, not the whole roof. Even 20% of a roof for example will provide quite a bit of water.