My first sump build! I have a few questions

Hello everyone. I started my first sump build but I have a few questions regarding flow rates etc. I'm building a 5.5"gallon sump for my 20gallon tank.

I am planning to build the DIY over flow in the link below that is all out of PVC piping.
http://www.aquariumlife.net/projects/diy-overflow/120.asp

The instructions say to us 3/4" piping. How do I calculate the water flow to find a suitable pump for the return. If I use 3/4" piping for the overflow, and the top of my tank is about 3 1/4 feet from the ground, how can I calculate the GPH? I've been looking at the Magdrive 3 pump to use for the return. Does the piping size on the return matter as well? Can I add a valve to the return to control the flow of the magdrive 3? And if I added the valve, do I just simply observe the flow and adjust as I start it up?

Should I use rigid pvc piping for the return and over flow from the tank to the sump? 90degree bends or no? Or should I use flexible tubing?

Also, I was wondering where exactly to drill holes on the outlet and return of the piping to create the siphon break in case of power outage.

Thanks in advance!

 

I am always looking to cut a few dollars out of my build budgets. But with overflows- one area I will not skimp - like lighting and skimming - a lot can go wrong when inferior designs are implemented.

The issue I see with this is that it relies on a power source to operate.

If you lose power on the vacuum pump or powerhead - your vacuum is lost. Once your power starts up again - you can easily have a flooded floor and a burnt out return pump and hopefully not a fire.

For your size tank - an overflow box would be something like 50-60 dollars.

I personally prefer Eshopps U-Tube style overflows. Been using them for nearly a year on my 120DT (2 of them working together) and have had ZERO issues after numerous power outages, water changes, and coral feedings.

To calculate your return pump, you should find out what the pump you are looking at will produce at the given head height. A lot of people have head heights of about 4.5' on average. For a Mag3 at 4.5 feet with NO fittings/turns/etc - you will be moving around 300 GPH. This would be more than sufficient for your 25.5 or so gallon system IMO.

Even the smallest Eshopps overflow box can handle this much flow with no problem.

Just be sure to put a valve between the output of the pump and the return nozzle on your return piping this way you can easily control the flow rate going to your overflow box.

If you have a return nozzle, the best thing to do to break the syphon is to keep the nozzle as close to the surface as possible. This way, in your 20 gallon tank with 5 gallon sump - you would only have a gallon or so of overflow. Be sure that your sump has enough auxillary capacity to handle the overflow when the power is turned off. Keeping the nozzle close to the surface will also give you good surface agitation IMO.

Drilling holes in the return plumbing is only a false sense of security. It does not take much for corailline or algae or a small snail to clog one (or all) of the syphon breaks - rendering the backup plan ineffective.

 

ocean man,I dont understand where you say the op needs a vaccuum pump.Also,I have used this type of overflow and could not get it to lose suction with multiple power outages.I was very impressed with the pvc overflow and when I build my next sump,it will have the same thing.

 

Thanks for the info. yes I was looking at the Eshopps and CPR overflows. They're about 60-70 bucks @ 300GPH. Not a bad price but I was hoping to have the fun of building something myself. About having the pump on the overflow, I thought the pump was just to suck the air out to prime the siphon? I did not know that it needs to be continuously working on the siphon. I'm not too sure.

I'm not too sure on the design either. I thought you just need airline tubing to prime the siphon. But once it started going, you could remove the tubing and cap it off?

 

I extrapolated that information from the OP's own link.

"Step 6 (If you have a powerhead) - Attach the aquarium air hose to the inlet of the powerhead to create a vaccuum. This vaccuum will automatically prime the overflow and it will begin operating.

Step 6 (If you don't have a powerhead) - Attach the aquarium air hose to a on/off valve. Open the valve up and suck on the end of the valve until you see water in the air line hose. When you see water in the air line hose that means the overflow is fully primed and should be operating. While maintaining suction on the hose, close the valve."


Have you had an opportunity to look at the diagram in the link? There is an external vacuum/prime line extending off of the top of the PVC. This relies on either a vacuum pump or powerhead. Both of these methods rely on power. If the power goes out and syphon is lost - flood will ensue. Simple as that.

Even worse is allowing at $1.00 check valve determine the fate of a $1000.00 saltwater system. Those check valves are prone to failure. Also, even the nature of the installation, being DIY AND involving water - there is no "Factory Seal" in the pipes when you drill and glue/tap the barbed fitting. This is why I use actual fittings which are designed to a standard in my plumbings systems which I rely so heavily on to be watertight and reliable.

That is not to say that a handy individual can tap and set a threaded connection - just far to easy to mess this one up IMO.

Build your own canopy - build the baffles in your sump, do all the DIY-ing that brings content to your heart. Just know full well that this is not the most elegant/reliable solution to an overflow available. And in a hobby where even a 20 gallon tank can easily run over $1000.00 by the time all is said and done - I'd sooner spend the $60 on an overflow I KNOW will work, then spend $20.00 and four hours on something that bit me in the butt a few months down the line - only to wish that I had spent that little bit more on a proper overflow.

The other major downside to this design is that you have no way of knowing (without a flexible camera) whether the inside of the overflow was nearly clogged, or was accumulating air bubbles.

With the clear U-tubes of the Eshopps overflow - you can tell both the cleanliness and efficiency of flow in the blink of an eye.

I assure you that my goal is not to discourage you from endeavoring in your own projects - there is little more rewarding in life.

But what I can say with confidence is I would not be able to sleep at night with even the potential of only 20 gallons of dirty saltwater on my floor . . . . let alone the 150 gallons of my system now.

 

This is correct, you do not need a full-time vacuum pump - but you need to maintain the prime in a potentially open system. All it would take is the SLIGHTEST pinhole leak in the on/off gang valve/check valve and everything is shot. Where is the failsafe in that?

Again, I totally agree with you on the joys of "DIY"!!!! But there is something to be said in paying for someone else to research and make the expensive/messy mistakes so that you do not have to.

There are plenty of opportunities in this hobby to DIY - IMHO - this is not one of them for a DT.

Perhaps if you really have your heart set on the DIY of the overflow - still go ahead and buy a premade (Eshopps or eq.) and still do the DIY. This way you have redundant backup if one or the other fails.

If this was for a refugium or isolated feed and you main system can handle the feed if the DIY fails - then I'd say go for it.

If not, you have been informed. . . . at the end of the day, you need to do what makes you happiest.

 

Thanks again for the info guys. Yeah I guess I will go for the CPR or eshoppes overflow. They do look a lot nicer. If I decide to go with these overflows, do they come with the tubing or do I still have to buy it?

I'm still not sure on what sized tubing/piping to go with for the outlet, and return line. Rigid pvc lines, or flexible tubing? If I decide to go with PVC lines, do I need to calculate 90 degree elbows in the GPH?

 

why not put an over flow in the tank itself and drill it? it is the safest way, and the least expensive IMHO. reason why? less pipes, there fore less pump size, runs cooler (smaller pump), less to look at, and certainly less to go wrong. Or run a HOB skimmer/refugium. every change in water flow (elbows) adds head presure on the pump side- that is to say- the more length and elbows the less output from your pump you will have..

 

If you can, drill baby drill. HOB Overflows can (and sometimes usually do at some degree) fail and can cause flooding. Internet overflows only depend on gravity and not a siphon so there is more comfort of reliability there. I really wish I set up my tank with an internal, but I spent the $$ and got a really good overflow. So far so good.

 

Thank you guys. Drilling is out of the question for me though. I wouldnt want to take it down and get it taken to a shop to be drilled. I'm thinking of getting the Magdrive 2 and the Eshopps Nano overflow @ 200gph. Do you guys think this will be a sufficient combo?