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View Full Version : Need Input on HOB Sump Design


DiverDude
04-10-2010, 07:03 PM
I've decided to add a HOB sump to my 29Gal bowfront. There are a number of reasons -extra water volume, a place for my new skimmer that won't take up tank space, a place for some form of mechanical filtration, a place for carbon and to put my heater.

I'm going to make it out of 6mm acrylic.

I have a few design issues I'm trying to sort out before I start building though and I'm hoping I can get some input from those here who have been there and done that !

Essentially, this will be a narrow, rectangular box that will be ~16" high x 18" long x 4.5" which will end up with an effective capacity of about 5 Gal. I'm planning on having several removable partitions for floss or sponge; to mount the skimmer on, and hold a carbon bag upright.

My questions centre around pumps and flow rates and managing the water level. The skimmer has a Maxijet 1200 (295 gph) so my thought is that whatever pump I use to pull from the tank, it should have a flow rate beyond that so I can throttle it (ball valve) to control the overall water height in the sump and to keep some flow in the sump so the skimmer doesn't end-up sucking up water it just skimmed.

For the intake, I want to do an overflow tube to skim the surface then come up, over the tank lip, through a ball valve, and empty into the sump (below the waterline to keep it quiet) into something like this sock holder (http://www.jlaquatics.com/product/of-csiha4/CPR+Single+Sump+Inlet+Assembly+(4+Inch).html). I'm thinking 1/2" pipe with a 1/2" to 3/4" adapter with 'teeth' cut into it for the top should be sufficient. Should I go 3/4" ? Ideally, I'd like to keep a powerhead out of the tank so can someone suggest a pump that I could mount on the side of the sump ? Would it be quieter/cheaper/easier to put a powerhead in the tank ?

Once water is in the sump, the skimmer is next: Bubble Magus BMQQ Skimmer (http://www.nuocean.com/bubble-magus-bmqq.html). No big deal here; it'll just sit there and skim. Downstream of that will be a carbon bag and some sponge to trap any microbubbles.

My last question is how to get the water back to the tank. My initial thought had been to heat-bend the acrylic into a waterfall like on an Aquaclear filter or Remora skimmer. I'm second guessing that now and wondering if it would be better (more quiet) to do a bulkhead in the sump and have a pipe empty into the tank below the waterline. The hiccup with that is that I'll raise the waterline in the sump and it'd have to be an inch or 2 taller to accommodate. Thoughts ?

I think I should be fine for a power failure situation (water level in the tank and sump should be roughly equal at all times). Priming may be a bit of fun but I plan to put some kind of removable cap at the top of the intake to pour water down to get it going.

Anything else I'm missing ?

BCOrchidGuy
04-19-2010, 09:52 PM
off the top of my head why not use another maxijet to pull water from the sump back to the main aquarium. Hard to explain but basically you'll siphon water from the aquarium to the sump and back into the aquarium... Or use a maxijet to push water from the main tank to the sump and have it overflow back into the main sump. This wouldn't address your wanting to skim the surface though.

Doug