Overflow GPH for 125 tank w/ 40 gallon sump?

[mikebusc]

Hello all and thanks for all the help I've been reading about so far. I've been out of the hobby for nearly 20 years now and I really didn't know a great deal at that time. I'm SLOWLY getting back into it now and I've been doing a lot of research for my new setup (which will be a mixed reef) and have used this forum a great deal. This is my first question so far. I purchased a 125 gallon Top Fin (will build my own stand though) and will be using a 40 gallon breeder for a sump. I have the Modular Marine low profile overflow which is rated at 1600 GPH. Is that too much? Overkill/ Or does it not matter? Does it have more to do with the return pump(s)? I haven't purchased the pumps yet as well as the skimmer etc. I did get a refugium kit to use in my 40 breeder.
I'd rather not have to try to return the 1600 if possible unless someone out there thinks it could be a potential problem. Thanks in advance and I'm sure I'll be back for more!

 

[griss]

The overflow is rated for up to 1600 gph. And, since it’s a through the glass design, it will function fine with water flow from 0-1600 gph

If it were a HOB overflow, it would be a different story.

Bottom line, you should be fine with any return pump up to 1600 gph.

 

[mikebusc]

Great! Thanks so much. I'm going to start building the stand soon as well as drilling the back of tank (Ugh). I'll still be doing a lot of research. Trying to cover as many bases as possible to save from failure.

 

[reefing102]

Welcome back to the hobby!

I’d I can make a recommendation, if you’ve never drilled a tank, perhaps buy a small 10 or 20 gallon tank to practice on. Also make sure that 120 isn’t tempered glass (not likely but you never know).

 

[T Diddy]

Hello all and thanks for all the help I've been reading about so far. I've been out of the hobby for nearly 20 years now and I really didn't know a great deal at that time. I'm SLOWLY getting back into it now and I've been doing a lot of research for my new setup (which will be a mixed reef) and have used this forum a great deal. This is my first question so far. I purchased a 125 gallon Top Fin (will build my own stand though) and will be using a 40 gallon breeder for a sump. I have the Modular Marine low profile overflow which is rated at 1600 GPH. Is that too much? Overkill/ Or does it not matter? Does it have more to do with the return pump(s)? I haven't purchased the pumps yet as well as the skimmer etc. I did get a refugium kit to use in my 40 breeder.
I'd rather not have to try to return the 1600 if possible unless someone out there thinks it could be a potential problem. Thanks in advance and I'm sure I'll be back for more!

In the olden times, we used to insist that the main pump be capable of turning over the volume of the tank at least 4-5 times per hour. So, after taking the pump head pressure into consideration, a 500 gph pump isn’t going to be enough. Pumps usually have a head-pressure graph available to determine water flow, but I’d say you’re safe with virtually any 800 gph pump. Obviously you can go higher, but I personally never go higher than the amount of water that one overflow can handle… if a snail or some other obstruction finds its way into the pipe, a 1600 gph pump is going to ruin your day.

 

[mikebusc]

Welcome back to the hobby!

I’d I can make a recommendation, if you’ve never drilled a tank, perhaps buy a small 10 or 20 gallon tank to practice on. Also make sure that 120 isn’t tempered glass (not likely but you never know).

I've watched a few videos on it and I feel pretty confident. I've read that this tank (it's a 125) is only tempered on the bottom but I'll do the polarized sunglass check on it. I'm an electrical contractor and I do various types of drilling so I think I'll be good.

 

[mikebusc]

In the olden times, we used to insist that the main pump be capable of turning over the volume of the tank at least 4-5 times per hour. So, after taking the pump head pressure into consideration, a 500 gph pump isn’t going to be enough. Pumps usually have a head-pressure graph available to determine water flow, but I’d say you’re safe with virtually any 800 gph pump. Obviously you can go higher, but I personally never go higher than the amount of water that one overflow can handle… if a snail or some other obstruction finds its way into the pipe, a 1600 gph pump is going to ruin your day.

Thanks for the info!

 

[mikebusc]

Just a general question about this forum......if I have more questions, most likely will, should I start a new thread if it's a different topic?

 

[Misled]

You can do it anyway you want. Most like to start a build thread so your progress can be kept in one place.

 

[mikebusc]

Ok thanks. My next step is with the position of my overflow before I actually drill. Is it always best to mount this dead center? Tank is 72" long. The overflow is 16" wide. Not sure why I'd want it off to one side at the back or even on the short side but just wanted to know my options. I've always assumed center was best. And am I just gluing PVC into the bulkhead openings for my drains?

 

[T Diddy]

Ok thanks. My next step is with the position of my overflow before I actually drill. Is it always best to mount this dead center? Tank is 72" long. The overflow is 16" wide. Not sure why I'd want it off to one side at the back or even on the short side but just wanted to know my options. I've always assumed center was best. And am I just gluing PVC into the bulkhead openings for my drains?

You’re going to want to get some bulkhead fittings to make sure that you have a good seal. They’re available in slip fit or threaded configurations

 

[T Diddy]

I just received some of these from saltwateraquarium.com …if using a 1” schedule 40 , you’ll drill a hole 1.75” to accommodate the bulkhead. Hand tighten only…don’t wrench it or they’ll crack.

 

[mikebusc]

Yes I have the fittings, they came with the overflow. Looks just like the one you're showing. Thanks for that. I guess I should have said does the PVC glue right into the "fittings". So I'm assuming that's a yes?
What do you think about the placement of the overflow? Stay away from the left or right side of the back and the short sides and just go with dead center?

 

[T Diddy]

Yes I have the fittings, they came with the overflow. Looks just like the one you're showing. Thanks for that. I guess I should have said does the PVC glue right into the "fittings". So I'm assuming that's a yes?
What do you think about the placement of the overflow? Stay away from the left or right side of the back and the short sides and just go with dead center?

Yep, you can glue the pvc in the bulkhead fitting. With the style of overflow that you’re going with, I’d probably go with center…it’s personal preference, really. I’m currently rebuilding my tank and going for a cave look, so I wouldn’t do the center overflow on it. Mine is predrilled through the bottom on the left and right corners.

 

[wvned]

The bulkhead fittings are probably ABS. You use a transition cement. It's available at Home Depot.
Drilling a tank isnt hard. Its a grinding process and not a cutting one. Press carefully very lightly or it will break out badly on the back.

 

[mikebusc]

The bulkhead fittings are probably ABS. You use a transition cement. It's available at Home Depot.
Drilling a tank isnt hard. Its a grinding process and not a cutting one. Press carefully very lightly or it will break out badly on the back.

Will do. Thank you!

 

[mikebusc]

Yep, you can glue the pvc in the bulkhead fitting. With the style of overflow that you’re going with, I’d probably go with center…it’s personal preference, really. I’m currently rebuilding my tank and going for a cave look, so I wouldn’t do the center overflow on it. Mine is predrilled through the bottom on the left and right corners.

Thanks for the reply. I'd like to see a pic of that cave look once you have it. Sounds interesting.

 

[griss]

I drilled my current tank 40BR, and put the eShopps overflow center. It would have driven my type A nuts having it off center or on one side.

 

[mikebusc]

I drilled my current tank 40BR, and put the eShopps overflow center. It would have driven my type A nuts having it off center or on one side.

Yes, I think I'm agreeing with you the more I think of it.

 

[jason2459]

I've got a 120 now with a 40 breeder sump and a centered external overflow I think is rated for 1600gph too. I would never push an overflow to its limit. I think I have about 800-900gph going through mine.

I had a Jebao DCT 15000 and currently a Jebao EP-10000. Nothing wrong with the DCT and can use it as a backup. I got the EP cheap. Based on head height (actual height, horizontals, pipe diameter, fittings, etc) I put the pump at a certain percentage and then dialed in the main overflow with a gate valve.