Okay thank you. I might try to quickly drill another hole. The no mechanical filtration is new to me, but I'm also fairly new to the hobby. I thought it was pretty much a must have. Would you replace bio balls with something else or take them out entirely? Flooding is something that I am concerned about. The second the pump stops it starts a siphon down so that's something I have to figure out. Thank you for your help
The flooding when the pumps stop is what
@Subsea was talking about previously. You need to make sure that if/when the pumps stop - like during a power outage, which will always happen when you're not home - that the water that drains back doesn't overflow the sump. I would seek Subsea's advice here, he's a well respected reefer and an engineer by trade.
You can install a check valve on your lines, which prevents water from draining backwards. However, many people hate check valves either because they've failed and caused a whole other problem, or because they need to be cleaned/maintained in order to prevent their failure.
Me personally, I would take out the bioballs. The problem with them is that even with the mechanical pads above them, they can accumulate detritus, which at some point is going to produce nitrate. Excess nitrate can fuel unwanted algae growth, but is otherwise fine for most fish and animals like turtles. If you want to keep corals, then excess nitrate can be a problem for them. Most reefers no longer use a wet/dry, trickle style filter loaded with bioballs (which is I believe what you have), we rely on the rocks and sand in the tank (plus good flow) to be the tank's main biofilter.
There is definitely a contingency of reefers here at R2R that don't use mechanical filtration, plus I know Josh from
World Wide Corals does not use any mechanical filtration at all. They see the material that mechanical filtration traps as food for corals and other creatures. Many of these reefers say that there is a healthy layer of mulm and build up in their sumps, but they consider that beneficial. I know one member here that when he started a new tank, he scooped all the mulm and crud from his old sump and added it to the new sump.
That said, I'm sure the vast majority of reefers use something for mechanical filtration. My point is that there's always more than one way to go about something, I would suggest not getting too hung up on things that you "absolutely must have to be successful". A protein skimmer would be another example of this. A skimmer is a fine tool, but far from a necessity to be successful.
Sorry for the long reply! I'm sure Subsea and others will be able to help with your plumbing questions.