Originally Posted by hoppycalif
It looks like the wood pieces rest on top of the substrate. That is an invitation for hydrogen sulfide to form under each of them, leading to very bad smells, and toxic problems for the plant roots. We need to sit pieces of hardscape directly on the bottom tank glass, with the substrate surrounding them, not sitting under the wood.
Thanks for the warning Hoppycalif. I've never had a problem with that in the past, even in an El Natural setup, but perhaps it had something to do with the substrate type and plant species I was running. My concern was always making sure I DIDN'T set the driftwood on the glass (anaerobic concerns with the wood itself), and was always told that keeping it on top allowed for the plant roots to access the areas beneath. I'm using a fired clay (Flourite) for substrate in this setup (does that matter?). I'll let it play out a while after the system is up and running and see if a problem arises.
Is there something specific I ought to watch for (bubbles coming up from that area, changes in water chemistry...)? Or is this more serious than that?