A few stupid questions about drip systems advice needed.

I am planning on building a drip system since I have 30 3 gal. buckets but have a few stupid questions and any advice and info would be appreciated.

1. To get a proper return flow how much higher do I need to have the pots to the res?
2. what size hose should the return hose be and where should the placement of the return hose be in the res container? in the bottom?
3. can I fill the hole 3 gal. bucket with clay rocks or should I do some kind of pot within the bucket or dose it not matter.
4. and lastly water pump size if I constantly water 18 pots in a 4x6 foot space? but would like to be able to expand to 27 pots in a 4x9 foot space.

thanks in advance.

Its simple gravity, The highest the water will be in the res, is at the height of the bottom of the lowest pots return line hole, if that makes since. The bottom of the bucket is best for the return line. The lower the return line the less water is gonna be in the bottom of the bucket for the roots to sit in. And it will happen. The return hose can be as large as u want it but i would say at least a quarter inch. You could fill the bucket with hydroton but its a huge waste, just get a net pot to sit in the bucket. There is no need for constant water. You risk overwatering, and its wasteful. You just need to keep the roots wet and not dry out. Thats where the hydroton kicks in. It withholds water really well so you can water once every 2 to 3 hours or longer for lets say 5 mins a time. Mine personally is set at once every 3 hours for 5 mins but I am going to set that back to 4 mins. And mine do fine. Altho you will run into a hundred different opinions. The pump your gonna need to talk to a hydro store for. Altho I no it would take a large res and powerful pump for 27 pots.

I have seen some drip systems for sale online that state the buckets only have to be 2 inches higher then the return hose in the res. It states all you have to do is place a 2x4 under the buckets... I thought that sounded strange since the levels are almost identical so I thought I would ask.

Much thanks