I picked up a used mag 5 pump for cheap and i wanna set up a 30G sump to my 55G tank. A few questions...I heard the rule of thumb is that you want turn your tank over 10X an hour through the sump. with a mag 5 at 4' that puts me at like 300 gph i think...not quite the recommended "550". What are the benefits of doing a full 10x an hour, or rather what would be bad about only turning it over ~6 times an hour?
Thats not quite right.
You want the tank to FLOW at least 10x per hour. Even 30x per hour is fine for a lot of corals. Lots of room here to adjust the tank flow.
You want 3x - 5x the tank volume through the sump per hour.
With a 55g tank, you would want between 550 - 1600gph flowing around inside - OR a combination of some flowing around inside and some of it going through the sump. Trying to push all that through your sump is going to make the sump look like the Colorado river during spring thaw. You'll have water rushing through there so fast that micro bubbles will go right past your baffles and end up back in the tank. Not good.
The Mag 5 is going to push about 510 GPH at 3 feet of head. You really only want about 150 - 250 GPH going through the sump. The Mag 5 can still be used. Just put a Tee in the main line that shoots the water back up to the tank. This is your return line. On the Tee, put a 90 and point it back down into the sump. Put a ball valve on the main return line. Now you can adjust the water going back into the tank by opening/closing the ball valve.
But wait a second.......... :frustrat: Thats somewhere around 200 GPH through the sump. You still need between 300gph - 1300gph flowing through the tank. WTF? :shock:
The difference is made up with powerheads in the tank. You can't push all that water through the sump. So, you run the sump at 3x - 5x the tank volume per hour and you make up the difference in the tank with powerheads. :Cheers:
Also, I think I'm gonna buy the EShopps PF-800 Overflow Box.
Eshopps PF-800 Overflow Box, Up to 100G, Single Intake
power outages are common at my place and of course i want to avoid floods. This overflow is good at restarting its own siphon ya?
I heard somewhere that you want to produce flow "close" to the overflow's max flow rating. Would only putting 300 gph through it not keep a good siphon? or would i be better off with the pf-300?
Thanks in advance.
Screw that man.
DRILL IT!!!
For that mag 5 return pump - let's always assume it'll be pushing the rated 300gph at 3 feet of head. In all reality, it'll probably be pushing much less than that due to pipe friction loss and any elbows or other fittings in the line. So we'll assume it's still pushing 300 gph and that will give us a nice safety margin.
Okay, so you need a bulk head and drain line that will flow 300gph. Here ya go. Scroll down the page and note the size bulk had needed to flow 300gph.
Bulkhead Flow Rate Art
Looks to me like you need a 1" bulk head.
Now go here
Buy flexible pvc pipe at FlexPVC.com PVC pipe, hose, & pvc fittings online @ wholesale discount prices (flexable) and buy a black ABS heavy duty bulk head - 1" size. The bulk head details will tell you what size hole saw you need. I've purchased 3 of these bulk heads. The numbers are accurate when they tell you what size hole to drill. I bought a hole saw exactly 1 millimeter larger than recommended.
Go here for your hole saw:
welcome to richontools.com and buy a diamond coated hole saw.
You can't drill the hole all the way up at the top of the tank, so you still need an internal overfow box with teeth inside the tank. You'll be drilling the hole about 2 or 3 inches below the top rim. Drill your hole, install the bulk head with the rubber gasket in the OUTSIDE of the tank. Snug it up hand tight and then go 1/4 turn tighter with a big pair of channel locks. It's sealed now. Don't mess with it.
Go to here and buy one of these internal overflow boxes. If you don't know which one to get - just call them. They will help you. Depends on if your bulk head is in a corner or in the middle of the tank. Couple different variables to think about when drilling the hole.
Internal Overflow Boxes
Silicone the overflow box inside the tank so the teeth are all the way up against the top rim of your tank. That will make the water level in your tank about 1/2 inch -- 3/4 inch below the top rim.
Scared to drill a hole in a tank? Don't be. It's EASY. Scroll through my tank build thread here. Page 10 shows bulk head installation. There's a TON of videos on youtube that will show you how to drill al hole in a glass tank with a diamond coated hole saw.
https://www.livingreefs.com/rcpilot-29g-frag-tank-t21142p10.html
Good luck!! :Cheers: :mrgreen:
