Backyard Aquaponics
A place to discuss aquaponics

Planning on using a 500 gallon fiberglass spa as a FT for tilapia. Don't have the GB's available now, so just trying to get a good scope on the size of the filter bed I would need for appx 20 fish 3-5" and hopefully future babies. Also, suggestions on the cheapest, easiest way to keep them happy. Can I use a small pump and just pump into a split 55gallon barrel with scoria in it. Thinking about using a 12/24 volt system with solar/battery. I have an additional AC/DC backup close by in my AP FT, that can be a backup. Thoughts? I may add additional GB's for AP off this large FT in future, but right now just trying to get these Hawaiians going.

One of the reasons I like AP especially for BYAP systems is because it is so simple.

Your system (in RAS terms) is tiny but designing it will pretty much take the same work as a large one. For RAS Timmons "recirculating aquaculture" is probably your best starting point.