Thanks Menagerie! I changed the title.
BillyZ, and the 40g is aquascaped for someone looking down into the tank? That'd be sweeeeet.
For the bulkhead, I'm now using a 90deg elbow with slits to skim the surface. Black pantyhose covers the return outlet. In the sump's plastic canister, there is open celled foam below the filterfloss. Flow rate is up to ~25gph after taking apart the powerhead and putting it back together (? - wasn't dirty but cleaned a little). I've added a prefilter to the return pump since I'm planning on a shrimp clean-up crew in the sump.
Nitrates aren't registering on my test and I think I've seen an increase in algae, so must dose nitrates (I think).
Because of increased water volume I added to the kuhlii loach and oto group. I think they like the company.
Temp increased to 78F with the heater unplugged and sump lights (13w) off. The PH
is submerged -- I guess I'm overheating the thing. Temp before sump was 74F with a 50w heater. Any suggestions? Low RPM fans (low noise is important) above the sump? Would you just buy a proper submersible pump instead of fiddling with a more powerfull powerhead?
injection at the sump is inefficent, and main tank's plants stopped pearling. Returned Hagen bubble ladder to main tank. Water in the sump is almost still. Is this likely due to CO2
absorbed in the return piping?
Thoughts on filtration are especially appreciated. I'm still considering wet/dry, but wonder if its worth the trouble with very low flow rate and a small tank.