It's really starting to come together. Nice to see the photo updates. It's already looking great.
Will you have UV to control green water or hoping the bio filter and biofilm will starve the algae from nutrients?
Are you able to bury the bottom drain Lines? To protect as well as hide them. If a tap valve gets broken, the pond would completely drain (?).
Also if air is essential then you can add a second air pump sharing the same line for redundancy. If one pump fails, the overall air volume drops so its immediately apparent but air supply continues until you repair. It doesn't look like air will be critical unless you have high stocking rates and the main fish is air breathing.
I forget to reply to one of your previous comments about 30kg bottom drain covers. Flat covers are easily influenced by water currents so a fish swimming past would move them. The trick is to attach a weighted column to underside of cover which extends vertically down into the drain pipe so it can't flip over or move sideways more than the drain width.
Will you have UV to control green water or hoping the bio filter and biofilm will starve the algae from nutrients?
Are you able to bury the bottom drain Lines? To protect as well as hide them. If a tap valve gets broken, the pond would completely drain (?).
Also if air is essential then you can add a second air pump sharing the same line for redundancy. If one pump fails, the overall air volume drops so its immediately apparent but air supply continues until you repair. It doesn't look like air will be critical unless you have high stocking rates and the main fish is air breathing.
I forget to reply to one of your previous comments about 30kg bottom drain covers. Flat covers are easily influenced by water currents so a fish swimming past would move them. The trick is to attach a weighted column to underside of cover which extends vertically down into the drain pipe so it can't flip over or move sideways more than the drain width.