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New tank overflow advice

Hockeynut

NJRC Member
What’s everyone’s opinion, do you think 3/4” will flow 800 gph?
I know most charts say no but what I have found in the past is that that gate valve is usually mostly shut such as Dave said.
opinions please
 

DangerDave

NJRC Member
I think that’s too small. What if you lose your syphon? You should size it to gravity fed for emergencies, because emergency. And the backup should be the same size.
 

motortrendz

NJRC Member
I would go 1in. I made the mistake of only having 1 3/4 full syphon drain on my frag tank and it's not really enough. And it's my fault I was lazy, and didnt wanna wait. My 1in bulkhead bit was dead so I drilled it for a 3/4 bc it was still a good bit. Wish I waited.
 

Hockeynut

NJRC Member
I think that’s too small. What if you lose your syphon? You should size it to gravity fed for emergencies, because emergency. And the backup should be the same size.
Sorry I miss wrote, I mean gravity, like in a Herbie. I have two 3/4” fully submerged pipes that go to a T to a 1-1/4” gate valve I also have one 3/4” pipe to adjust the flow and another 3/4 for emergency. And want to flow about 800 gph.
 

DangerDave

NJRC Member
right but if you get get a clogged pipe, will the emergency pipe support the entire flow without a syphon? I think that is the question.
 

Hockeynut

NJRC Member
right but if you get get a clogged pipe, will the emergency pipe support the entire flow without a syphon? I think that is the question.
It is highly unlikely for 4 pipes to clog simultaneously, but let’s say the gate valve clogs, the adjustment pipe which has no restrictions and the emergency with no restrictions combined should easily carry 800 gph
wouldn’t you think?
 
If you can get a velocity in the pipe it is easier to figure out but assume you have a velocity of 4ft/s (this might be a bit a bit on the optimistic side it is probably lower) since we are talking gravity. A 3/4" schedule 40 PVC flows ~5.5 gpm.
 
just sold a marine depot elite large i was going to use on my 150. i never got to use it but build quality was very good. work of art really. couldnt tell you about performance but not a bad option @around 100$ with a coupon.

i was worried it might have a waterfall sound some claim on certain different brands, never found out if it did
 
Looking into ordering the overflow soon that will be going on the 180 penisula I am working to get up soon. . What flow rate do you all recommend. I was thinking the 2400 GPH would be best for my application , is this too much? , Or do you think the 1800 GPH would flow enough? I figure that the 2400 can be throttled back if needed to reduce flow where as the 1800 would only allow 10x max water turnover . Something I am missing here or is my logic correct ? Thanks guys / gals
 
I think 3-5x is a better tank turnover rate, and getting the extra flow from the power heads imo. This gives your fug more time to do its job and you don't need such a powerful pump running 24/7.
Is the returns going to be next to the overflow or on the opposite side?
 

diana a

Staff member
NJRC Member
Moderator
the 1800 is for systems up to 200g. There is a 2400 for systems up to 300g
 

Hockeynut

NJRC Member
Is this the size you ran on your 180 ?
Yes more then enough, and dead silent, love this company. They make great products.
has three 1-1/2” drains way more than enough.
I ran one full under water with a gate valve. one at water level with a drip. And third as a emergency. Worked perfect
At 1800 gph your gonna be ripping water through that sump it better be a biggun
I would probably run it a little slower myself.
 
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Salted

NJRC Member
Happy to have run across this thread. My 75 is not drillable and I've been wanting to upgrade to a sump from my canister filter. I also want a fuge as I'm having a hard time getting my nitrates down. I went an ordered this; Marine Depot Overflow Box OF-800 - Marine Depot. I also bought a 20l with the petco $1/g sale last week. Adding it all up though now that I need a baffle kit for the sump, a return pump and an in sump skimmer it looks like this will be a several hundred dollar project. I'm probably going to keep running my reef octopus hob skimmer while I wait for a deal on a used skimmer. I can still set it up and lose my canister and start a refugium.
 

DangerDave

NJRC Member
Happy to have run across this thread. My 75 is not drillable and I've been wanting to upgrade to a sump from my canister filter. I also want a fuge as I'm having a hard time getting my nitrates down. I went an ordered this; Marine Depot Overflow Box OF-800 - Marine Depot. I also bought a 20l with the petco $1/g sale last week. Adding it all up though now that I need a baffle kit for the sump, a return pump and an in sump skimmer it looks like this will be a several hundred dollar project. I'm probably going to keep running my reef octopus hob skimmer while I wait for a deal on a used skimmer. I can still set it up and lose my canister and start a refugium.

I had a similar unit. I replaced it with a diy version made with 1 inch pvc that had much more flow and included a bypass for possible clogs (long story, but it all flowed to an algae scrubber), It worked great for a decade, but even with an aqua lifter running 24/7 to maintain syphon it always was in the back of my mind for failure.
 
Happy to have run across this thread. My 75 is not drillable and I've been wanting to upgrade to a sump from my canister filter. I also want a fuge as I'm having a hard time getting my nitrates down. I went an ordered this; Marine Depot Overflow Box OF-800 - Marine Depot. I also bought a 20l with the petco $1/g sale last week. Adding it all up though now that I need a baffle kit for the sump, a return pump and an in sump skimmer it looks like this will be a several hundred dollar project. I'm probably going to keep running my reef octopus hob skimmer while I wait for a deal on a used skimmer. I can still set it up and lose my canister and start a refugium.
are you sure you can't drill it? I'd check side panels, those are usually not tempered.

as far as baffles, I found some 10g tanks I cut up and used. I have a lot of glass left over. you are welcome to a few pieces if you like.

as far as return pump goes, I would get a jebao or just whatever. flow in sump shouldn't be very fast anyway. you can get away with as little as 225 gph. they used to sell some $20 pumps at Petco. imagitarium 300 gph I think. that would probably be fine.

look around for a used ASM skimmer. I've bought a g2 and g3 very cheap. g2 would be more than enough for you
 
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