PVC overflow to fast for pump?

[Hawke1974]

Hey guys. I just built a DIY PVC overflow with 3/4 PVC. I'm using a maxi 1200 for the return pump rated at 295 GPH... its really close to the correct ratio... but the over flow is filling a bit to fast... is there a way to slow the over flow down? the inlet on my PVC O.F. is all the way at the bottom of my tank a 75g rectangle.

Here's what I built:

 

[mcgyvr]

yes..
step 1.. throw that piece of crap in the trash.
step 2.. buy a proper overflow or drill the tank.

Thats just an accident waiting to happen.
Guess what happens when a snail or piece of debris partially blocks the overflow?
Guess what happens when the power goes out?
Guess what happens when the flow of the maxijet decreases?

 

[billdogg]

Sorry to be blunt, but I agree with the above post. If you still want a diy overflow, the section in the tank should be as close to the surface as possible, so that when you do lose power, only a small portion of the tank will drain. If I am looking at it correctly, the way you have it now it will drain the entire tank. Even if your sump is big enough, none of your fish (unless you have a lungfish, lol) and most of your corals will not survive more than a very short time without water.

Drilling is still the best option. I have yet to have a gravity drain fail on me. regardless of the type you use, be it Durso, Herbie, beananimal, etc, gravity works, all the time.

 

[rovster]

yes..
step 1.. throw that piece of crap in the trash.
step 2.. buy a proper overflow or drill the tank.

Thats just an accident waiting to happen.
Guess what happens when a snail or piece of debris partially blocks the overflow?
Guess what happens when the power goes out?
Guess what happens when the flow of the maxijet decreases?

Very funny, and so very true!

 

[Rbs07fxstc]

Plus with what you built, there is no surface skimming. And the hole will suck up any fish or whatever gets near it & likely clog & pump will flood your tank. There's nothing wrong with using an ordinary overflow box. I used one for years & didn't have problems. As long as you keep it clean & setup properly they will work problem free.

 

[biglurr54]

I ran two of these overflows in my 29 gallon with a quiet one 2200 return. I had the pump throttled back a bit. I could usually get one overflow to work and the other wouldnt. very rarely would I get both to work properly. It was a mess. You will hate that thing. Do yourself a favor and drill your tank or search the classified adds and find a used overflow. Your design is flawed but it will work but it will empty your tank. If you must use this kind of pvs "Double Siphon" you have to add another elbow in the tank that will send a tube to the surface. Where ever the opening is in the tank is where the water will level out. This is not only an issue wit power failure but that design you have right now will empty your tank into your sump because the flow down will be faster than the pump can return. (think of a garden hose siphoning water out from the bottom of the tank) If you move the inlet to the level you want the tank to be at then it will only suck water when it gets above that level. (move the garden hose to the surface) Try your system out and you will find out with in a few minutes that it wont work.

The PVC overflows work but just barely. You will still occasionally flood and they wont work half the time. if you are going to use them make sure you have 2 in the tank (redundancy) that will both take more than the pump can put out alone. Also a bio ball fits nicely in the intake side of 3/4 elbow to keep snails out.

 

[WillM]

I have two (redundancy) that are similar to that on a FW cichlid tank, but the tee on the outflow side is what determines the level in the tank. Mine is very close to the surface and that keeps it from draining the tank. If you want to use that you will (as someone else mentioned) have to add another elbow and section of pipe on the inflow side. That will help with surface skimming and keep it from draining the tank if you lose power. Also, you are going to want to get a Tom's aqualifter or some other device to hook up to the airline on the top. I can see the check valve, but that $2.49 checkvalve is what is standing between you and wet floors and burnt out return pump. Just an FYI, mine are built correctly exactly to the schematics on MFK and there are two of them for redundancy and they still for no apparent reason have overflowed twice when the power went out. Spend the $100 on a real overflow box and you won't regret it. Or drill it.

 

[mfinn]

yes..
step 1.. throw that piece of crap in the trash.
step 2.. buy a proper overflow or drill the tank.

Thats just an accident waiting to happen.
Guess what happens when a snail or piece of debris partially blocks the overflow?
Guess what happens when the power goes out?
Guess what happens when the flow of the maxijet decreases?

I agree completely.

 

[uncleof6]

Hey guys. I just built a DIY PVC overflow with 3/4 PVC. I'm using a maxi 1200 for the return pump rated at 295 GPH... its really close to the correct ratio... but the over flow is filling a bit to fast... is there a way to slow the over flow down? the inlet on my PVC O.F. is all the way at the bottom of my tank a 75g rectangle.

Here's what I built:

Physics say: the "overflow" cannot drain faster than water is put in the tank. It is not possible. Water out = water in, in all cases. So if you "want" to slow down the drain, you have to slow down the flow into the tank, by restricting the pump output. Physics also say: that if you want this contraption to work properly, the flow must be "laminar", meaning the pipe needs to be < 1/4 full of water, due to the fact that air is entering the system. The more water in the line, the more bizarre the behavior will be—exactly the same as every other open channel drain. (allows air in the line.)

By definition, this device is NOT an overflow. It is a cross/hybrid drain, attempting to utilize over the back siphon tube, with open channel drain. Unfortunately, the "tube" cannot siphon, because air enters the line, so the laminar flow rate for the system as a whole is down to < 50 gph.

For this device to function as an overflow, even remotely, the inlet must be at the surface of the water, so surface skimming occurs. But at the surface, the device will always suck air in through the inlet, thus complicating efforts to get even 25 gph through the drain system. Even at that, the overflow "consists" of the circumference of the inlet, which is horribly ineffective at skimming the surface of a marine system, regardless of the tank size.

How do you fix it? Put the inlet at the surface and adjust the return pump output till water gently flows into the inlet, (Pathetically low flow rate) or as already suggested, throw it in the trash can and buy a real overflow system/drill the tank. (LifeReef not ESHOPPS) These "diy pvc overflows" do not work as advertised, and they never have. The phsyics say they can't. Supporters of this device like to argue this "opinion", however it is not an opinion.

 

[gbru316]

I'll also add that at any sort of head, that maxijet 1200 is pushing nowhere near 295 gph. At 4' of head, you're at 125 gph, max.

As others pointed out: purchase a proper overflow, and add in an appropriate pump.

 

[uncleof6]

I would also add, that though its sounds like we are bashing you around, that is not the intent. The intent is that you receive the proper information, rather than the plethora of mis-information piled higher that Mt. Everest, concerning this type of system, and drain systems in general.

 

[Hawke1974]

Thanks for the replies.

 

[Hawke1974]

Can anyone offer any good DIY projects for a real over flow as I don't have the extra cash for a "Retail Overflow" and my entire tank is Tempered Glass so drilling is out of the question... and I must also add that when I initially purchased the tank, and got it started, I was working with Petco, and Discovered (After the fact) that wasn't the BEST source of info... but none the less I've gotten it started and need to work to correct my mistakes... preferably sooner than later...

 

[Rbs07fxstc]

Well your already on the right path by coming here. There is a DIY section on the forum. I'm sure you could find something. We've all made mistakes & sometimes still making them. It's part of the hobby unfortunately.

 

[mcgyvr]

being blunt again.. If you don't have enough money for a $100 overflow then just get out now.. "reefin' ain't cheap"

stick around.. read a bunch..start that piggy bank and just enjoy others tank pics for now..

 

[Hawke1974]

There's always a way to DIY ... I just need to find THAT way lol ...

For the record I managed to get the thing working, and it's been running for nearly two hours now... obviously a lot more baby sitting until I can get a couple fail safes put together ... But I'm learning, and that's the important part...

In the meantime I think I'm gonna talk to a LFS in the next city over that needs some Website work done, and barter for some parts

 

[dartier]

You are correct there is always a way to DIY ... however if your entire tank is tempered, you are better off buying an overflow. I know they charge ridiculous prices for them around here, but I would check eBay as lots of aquarium stuff can be ordered direct from China these days and the prices tend to be a lot lower.

As well the DIY approach will probably cost more in the long run. When I built my overflows I used Mr. Wilson's design. It still cost me over $100 for the parts.

I built two of these to get 30+ inches of surface skimming. The pics is of 2 units, 1 assembled and 1 in parts. There is 1.5" PVC pipe missing from the parts shown that has cut outs in it and acts as the main structure of the overflow.

I do mostly DIY stuff, but not because it comes out cheaper (or better), it often doesn't, but because I enjoy the process.

Dennis

 

[Hawke1974]

Yeah it has cost me more than I expected to DIY this overflow... but like you, I enjoy the Learning process, and the act of building something by hand that works... I finds highly it enjoyable, and rewarding...

As far as affordability.. I can afford the hobby... I think I'm giving up the R/C thing, as The kids, and I haven't done much with it lately... and put the money into this, at least this way, we can learn something science related together... a great way to bond with them too...

And I never thought to check EBAY... is that Chinese stuff reliable?

 

[BoricuaMojao]

I recently started back into the hobby, so I am perusing the for sale ads and craigslist often. I have seen commercial U-tube overflows, and CPR overflows for as low as $25

Just keep an eye out, they come along every so often. Check if there is a local club, someone is bound to have one in their closet of unused stuff.

 

[dartier]

And I never thought to check EBAY... is that Chinese stuff reliable?

Like everything, it depends. Much of what we buy in the hobby today is made in China anyway (though sold under name brands). There are even a few well known brands that are based in China (E.g. Bubble Magus).

For an overflow, if a plain jane overflow costs $100 and a plain jane one in China costs $35, then it is reasonable. You will however have to vet the different models and brands.

I often see things in stores locally and then find the same item on eBay from China under a different name, but exactly the same.

Dennis