Sump Question

[panda]

Hello all! I have what is probably a dumb question but I can't seem to find the answer.
A little background ... my husband and I have a 75g FOWLR that has been running smoothly for 2 years now, aside from one minor catastrophe when our A/C went out during a record heat wave. Blerg, that was awful.
Anyway, I love the FOWLR but, as was probably inevitable, I've gotten the bug to try some corals and/or anemones. Our 75 does not have the lighting or filtration for that though and, honestly, before I spend the money to upgrade the 75 I want to try something a little smaller to be sure that I like it first. I was thinking a 30-40g with a 10-20g sump or something along those lines.
So, I've started doing some research, particularly about the sump since we've never had one before and I'm a little confused about the flow rate of the overflow box and the return pump. I've been looking at the smallest of the CPR overflow boxes, which is 300 gph. For whatever reason (and maybe I'm just not looking in the right places) I'm finding pumps that are 294 gph, 296 gph, 320 gph, etc. Close but not exactly 300 gph like the overflow. It seems to me if the overflow is 300gph but the pump is only 294 gph then the sump will flood because the overflow is letting water in faster than the pump is taking it back out. And vice versa if the pump has a higher flow rate than the overflow ... the main tank might not flood but the sump would end up emptier than intended.
So, do I just get a larger pump that says it is adjustable and then just try as best as I can to adjust it to the same flow rate as the overflow? Am I over thinking this? I want to do this right and am feeling pretty confident about our ability to handle it but for whatever reason this one thing has me kind of stumped!
Thanks in advance for any advice and sorry this was so long!

 

[snakeblitz33]

Welcome to the Boards! I hope you enjoy your stay!
Are you just experimenting with a smaller system to get your feet wet with a reef system?
A 20g long sump would be perfect for a 40g breeder tank. You could pick up both of them at a $1/g sale at the big box store when they have their sale.
Baffle it with glass as thick as the tank itself, and use aquarium grade silicone or silicone that is not mold and mildew resistant. Design your sump on paper first, before you do it for real. Also, take into account what protein skimmer you are going to use. I personally use an SC65 skimmer on my nano tank, and it's working wonders. Also, consider adding a small section in the sump for a refugium so you can grow macroalgaes to help with nutrient export. A skimmer combined with a fuge and water changes will keep your water really clean for your corals and/or anemones.
I highly recommend using Eshopps brand overflow boxes. They do not require a lift pump to maintain siphon, and I have never had a siphon break on me. Another option is to just get a tank that is already drilled with an internal overflow. You can special order them at your local fish store. In general, it costs around $80 to get an internal overflow, which is pretty much the safest way of going.
To make your question even more complicated, you have to account for head loss! That means that a pump pushing water vertically looses a certain amount of GPH with every foot of vertices! That means a pump that pushes an average of 300gph at 0ft of head will only pump 230gph at 4 foot of head!
The siphon in the external overflow will only siphon out as much water as is being returned. The only problem is if you don't have enough water flow going through the siphon tube. That's why it's necessary to oversize your pump, accounting for head loss and throttle it back a little.
If you get a 40g breeder aquarium for a display tank, you will need:
Eshopps PF Nano 300gph
Mag Drive 3
A mag drive 3 pushes 350gph at 0 foot of head but 257gph at 4 foot of head with 3/4" PVC. An E-shopps PF Nano 300gph can not drain 300gph - that's it's absolute max. The main reason to upsize the pump is to account for head loss and to push enough water through the siphon tube to keep bubbles from building up in the tube and breaking the siphon. Also, it's good to put a ball valve on the PVC to throttle back the flow if you need to. Though, I don't think you would.
All in all, it's better to have a bigger pump than your external overflow so that bubbles won't break your siphon.

 

[geoj]

Hello all! I have what is probably a dumb question but I can't seem to find the answer.

A little background ... my husband and I have a 75g FOWLR that has been running smoothly for 2 years now, aside from one minor catastrophe when our A/C went out during a record heat wave. Blerg, that was awful.

Anyway, I love the FOWLR but, as was probably inevitable, I've gotten the bug to try some corals and/or anemones. Our 75 does not have the lighting or filtration for that though and, honestly, before I spend the money to upgrade the 75 I want to try something a little smaller to be sure that I like it first. I was thinking a 30-40g with a 10-20g sump or something along those lines.

So, I've started doing some research, particularly about the sump since we've never had one before and I'm a little confused about the flow rate of the overflow box and the return pump. I've been looking at the smallest of the CPR overflow boxes, which is 300 gph. For whatever reason (and maybe I'm just not looking in the right places) I'm finding pumps that are 294 gph, 296 gph, 320 gph, etc. Close but not exactly 300 gph like the overflow. It seems to me if the overflow is 300gph but the pump is only 294 gph then the sump will flood because the overflow is letting water in faster than the pump is taking it back out. And vice versa if the pump has a higher flow rate than the overflow ... the main tank might not flood but the sump would end up emptier than intended.

So, do I just get a larger pump that says it is adjustable and then just try as best as I can to adjust it to the same flow rate as the overflow? Am I over thinking this? I want to do this right and am feeling pretty confident about our ability to handle it but for whatever reason this one thing has me kind of stumped!

Thanks in advance for any advice and sorry this was so long!
If You are going to buy a new tank then buy one that is reef ready. That would mean it is drilled in the bottom and has a bulkhead in the tank like my tank or is drilled in the back and has and overflow like a Glassholes overflow.
The pump should put out less gph at the head high of the overflow or the display tank will flood on to the floor. So it is very important to read up on the pump and to know how high the water has to be pumped up to.
My tank

Glassholes overflow

 

[geoj]

The water in the sump is pumped up to the display tank and then drains back. So no more water can leave the display then is pump up in to it.

Siphon overflows are only as good as the siphon. If for some reason the siphon is broke water will not drain to the sump and the display will flood.

 

[geoj]

A drilled overflow will only flood if block by some obstruction. So the larger the overflow pipe vs the pump the less chance of flow blockage flooding the floor.
Then there is when power cuts out or is turned off. All water that is in the lines drain to the sump but is not pumped back. If the sump is ran with to much water in it then when the power is turned off the sump can flood the floor.

 

[flower]

Quote:
Originally Posted by Panda http:///t/389895/sump-question#post_3448986
Hello all! I have what is probably a dumb question but I can't seem to find the answer.
A little background ... my husband and I have a 75g FOWLR that has been running smoothly for 2 years now, aside from one minor catastrophe when our A/C went out during a record heat wave. Blerg, that was awful.
Anyway, I love the FOWLR but, as was probably inevitable, I've gotten the bug to try some corals and/or anemones. Our 75 does not have the lighting or filtration for that though and, honestly, before I spend the money to upgrade the 75 I want to try something a little smaller to be sure that I like it first. I was thinking a 30-40g with a 10-20g sump or something along those lines.
Hi and again...WELCOME!
You don't need any more filtration than what you have on the 75 already. A sump is nice, and I recommend it because it's the best system, but not necessary. The only upgrade you need are the lights. Depending on the type of corals you want to keep will dictate how strong of a new light you need. Your choices...Power compacts, T5 HO, LEDS or Metal Halides.

 

[panda]

Quote:
Originally Posted by SnakeBlitz33 http:///t/389895/sump-question#post_3449010
Welcome to the Boards! I hope you enjoy your stay!
Are you just experimenting with a smaller system to get your feet wet with a reef system?
Sort of, yes. But also, we were already planning to upgrade the 75 to something in the 125-ish range in the next year or two. If we both like the reef we'll probably just leave the 75 as a FOWLR until we are ready to change it out for something larger since we were planning that anyway in the not to distant future. Or if I like the reef and Mr. Panda doesn't (which is a distinct possibility since the current interest in trying a reef is all me) then nothing has changed in the larger system, which he is currently happy with. Plus, we've had to compromise a lot on fish for the 75 because we both like different things, too. With two separate systems I can see how I like the reef system without changing anything about the 75 AND we can both get a few of the fish that we were previously having to compromise on.
Quote:
Originally Posted by GeoJ http:///t/389895/sump-question#post_3449015
If You are going to buy a new tank then buy one that is reef ready.
I know that is what is best as far as being easier and having less of a risk of flood. But I really think I would learn more from having the separate parts the first time. I'm a hands on learner and I really feel like I am going to learn more about the physics of the whole thing with an overflow box. Maybe that's stupid but it feels right to me at the moment. Later, if I decide it was a mistake I can always swap it out for a drilled tank. If we ended up deciding to convert our larger system to reef we would probably do that when we upgrade to larger system anyway as I mentioned above and if we did that we would certainly buy drilled at that point.
Quote:
Originally Posted by GeoJ http:///t/389895/sump-question#post_3449020
The water in the sump is pumped up to the display tank and then drains back. So no more water can leave the display then is pump up in to it.

Siphon overflows are only as good as the siphon. If for some reason the siphon is broke water will not drain to the sump and the display will flood.
This picture really helped me understand it. I mean, I understood it before but this really made it click for me. Thank you.
Quote:
Originally Posted by Flowertrong> http:///t/389895/sump-question#post_3449060
Hi and again...WELCOME!
You don't need any more filtration than what you have on the 75 already. A sump is nice, and I recommend it because it's the best system, but not necessary. The only upgrade you need are the lights. Depending on the type of corals you want to keep will dictate how strong of a new light you need. Your choices...Power compacts, T5 HO, LEDS or Metal Halides.
See above for additional reasons for the second system. They larger system may or may not eventually be upgraded.
I'm thinking something like the second picture at this link for the sump layout: http://www.melevsreef.com/acrylics/sumps/glass/index.html From what I understand, you want your return section to be fairly large because that's where evaporation will show up. But I'd also like a fairly large refugium. It seems like this design with eggcrate as part of the baffle between the return and refugium would accomplish both goals because then the water level is then the same in both sections. Does a design like this seem good?
Thanks everyone for all your advice!

 

[geoj]

Sounds good to me. I also like to know why one way is better then the other and sometimes you have to see it for yourself. Over the years I have been flamed many times for keeping tanks as I do. Yet I can see very clearly, I have debunked many myths that still are propagated today because I check for my self if the information I read is right for me and the way I like to keep my tanks.