pepetj

I found this interesting design for DIY PVC overflow to feed Wet/Dry sump filters. Credits to Necromancer at Oscarfishlover.com who posted the pic I attach here without permission (he would likely grant it though).

Note that the T going into the sump must be above the level of the U shape inside the tank. The air check valve is to make easier draining trapped air to restore water siphon.

He published the following table in which the PVC diameter is correlated with the pump/powerhead needed, I assume this is the upper limit.


3/4" = 330 GPH
1" = 600 gph
1 1/4" = 910 gph
1 1/2" = 1,300 gph
1 3/4" = 1,800 gph
2" = 2,350 gph
2 1/4" = 2,960 gph
2 1/2" = 3,650 gph
2 3/4 = 4,450 gph
3" = 5,280 gph

Pepe
Santo Domingo

Attached Images

overflow1.jpg (39.8 KB, 572 views)

pepetj

I built one with 1/2" PVC and it works wonderfully. I am building another one since I am going to run two tanks with the same Wet/Dry sump filter.

My PVC pipe overflow is quite short in length since the tanks I'm placing them are both 13" high, and placed at 10-3/4" from the floor.

I'm using two Powerheads rated at 185GPH each (one per tank); of course only one is powered-on at the moment.

Promise to post pics once the second unit is finished.

Pepe
Santo Domingo

aabaltz

does it keep constant syphon, or does it need to be restarted if pump loses power....maybe this will be the overflow that i use.

pepetj

It keeps the siphon in stall and re-starts without problems.

Pepe
Santo Domingo

sirdarksol

The one part of this that I'm not getting is the "vent" I would think that any opening in the system would allow water to drain out of it.

Peterpiper

Not if it is higher than the water level in the tank, plus the water running to the sump would make a slight vacume and want to pull air in.

JRunyon21

I am currently undergoing an install of a 75 gallon in my house right now. All I have are the tank and some stand plans lol. The next step is an overflow. I am very cheap(75g - $40 on ebay, stand - $30 from 2x6's) and would like to make a cheap overflow. This setup looks great but I do not know what size PVC to go with nor would I know how large of a pump I would need. As stated before this will be a 75 gallon tank with a 20 gallon SUMP. The SUMP is a bit undersized but this will be a freshwater/brackishwater setup and it is merely a place to hide things I do not want in the tank.

I understand the pump should be sized under the PVC gph so you do not drain the SUMP. Bascially what I'm asking is, what is a good turnover ratio for a 75 gallon tank? 300gph? 500gph? 1000gph?

pepetj

I believe 300GPH to be on the lower safe side for 75gal tank, keep in mind you will loose GPH with increased height, so if yo are pulling your water say 2-1/2feet upwards, look at the chart that comes with the powerhead/water pump to check the estimated GPH you will end up getting.

The 300GPH info I got from my Pro Clear Aquatic Systems model 75 Wet/Dry filter. A 10gal volume in the sump area should do it, which usually is achieved using a 20gal tank in a DIY wet/dry sump filter.

Pepe
Santo Domingo

aabaltz

where to get one of those little check valves?

sirdarksol

They sell them at nearly every fish store. They are normally used to prevent a siphon if an air pump gives out.

aabaltz

i built one also using the half inch pvc, and a lees check valve from petco... i set it up in a 5 gal bucket in my bathtub under the faucet for waster supply, when air is initially removed from pvc syphon works beautifully, but when i shut off water and bucket drains down to height of inlet, then wait for water to stop( pump or electrical failure simulation) then turn the water back on, the syphon does not continue. what gives?

pepetj

I built two and mine stay in stall and restart right away.

Is your check valve placed in a way that no air goes inside the PVC? It looks like your assembly is not airtight.

I used PVC cement to seal everything. If you go with it be careful to let it cure for two hours at least before using it, and even then, the volatile gases trapped inside are nasty (now you know I breathed those disgusting fumes for not waiting as I should have... LOL).

I am replacing the 1/2" for 3/4" (ended up interconnecting two 30gal tanks) and using a 360GPH pump there.

Pepe
Santo Domingo

aabaltz

fisrt i dry fit everything, then once i was happy with the design i cemented all the fittings and pipes together letting them cure over nite, then i drilled the hole for the check valve, put aquarium safe caulk around the bottom of the check valve, then put it into its hole and put more caulk around the bottom where the check valve meets the pvc, and let that sit overnight to cure. when testing, i hung the setup over the side of the bucket, then filled the bucket w/ water to the point where water could run into the system, sucked out the air to get the syphon going, the turned the faucet on a slow steady stream and watched the water flow through.the whole system seems to work wonderfully after the initial start. after watching it for about a minute, i shut off the water from the faucet. as the water came to a trickling halt, i went away for about 5 min, then came back to restart the water. the water would flow but not nearly as fast,( air in the system) so i would have to bleed it out, then it would work fine again. After thinking about the whole setup last night i came up with a new plan, and tried it again this morning. I realised that yesterday i overlooked something. when i was running the faucet in the bathtub, the syphon system worked great, by my flaw was that there was too much water running in the bucket and the water was going over the top of the overflow ( when i get my new pump, with the adjustable gph this will be solved) so even though the system worked fine, when the water flow was shut off, the water level would decrease to the bottom of the inlet, and as it lowered passed the top part of the overflow air was brought into the system. keeping the top of the inlet above water is the key(in my opinion) so basically i think that i wsa just in a rush and overlooked some things. live and learn.

pepetj

Thanks for posting your experience, that's helpful info.

There's a way around adjustable powerheads, which I use wiht powerheads that aren't: I left the venturi hole open, so water can flow out; I place a plastic ball valve, which I close and then open it mid-way, if the tank water level goes way up the intake of the PVC overflow and/or the water inside the sump goes down too fast, I close the ball valve a bit and then some if needed. On the other hand if the tank water levels go down the intake PVC overflow and/or the sump is getting too much water, I open it a bit more.

That's how I adjust the working range of my non-adjustable powerhead in the Wet/Dry sump filter I'm using the PVC overflows (two tanks using the same Wet/Dry sump).

Pepe
Santo Domingo

JRunyon21

Keep the top of the inlet above water? Now I am confused. I was planning on putting mine together in a few days and this just threw me off. I'm probably just getting confused with the terminology but if inlet/intake is above water then how would water get in the system?

pepetj

The idea is to have the inlet submerged very close to surface level to prevent water spills during powerhead/water pump power outages.

I keep the outlet (return from the powerhead) slightly above water level so it doesn't siphon any water back into the sump.

Pepe
Santo Domingo

≈ D ≈

Dark_Rider2k3

I tried making something like this and seems like i'm not getting a good siphon. When I try and suck out the air, the water tickles out. does this mean that I don't have it airtight or what?

sirdarksol

Okay, so I'd just like some verification here, because I'm thinking of making one:
The inside part, of course, is set at the desired water level.
The vent is above the water level, but does it have to be below the part of the setup that goes over the back of the aquarium?

pepetj

The vent (open ended section) that extends after the T section should go a bit higher than the superior inverted U. The vent is used to let air in so water keeps flowing through the output, in the T, that goes to the (usually wider) hose that brings the water into the trail in the Wet/Dry.

Also, through the vent aperture, I use a turkey blaster to put water in the assembly in order to start the siphon as air is driven out though the air check-valve.

I ended up placing a ball valve at the end of each T so I can shut-down or even regulate water flow if needed be (I'm setting two adjacent tanks with the same Wet-Dry sump filter). I painted the PVC assembly part that goes inside the tank with black epoxy spray paint, I'm waiting for the Epoxy paint to cure to get the system running.

Pepe
Santo Domingo

JRunyon21

I need some help with the PVC Sump I plan to build. I am a bit confused on where to put the intake in reference to the top of my tank. I do not want my water level below the trim at the top of my tank. I also have read that the placement of the T going to the SUMP plays a big role on my water level as well. Anyone have any ideas of how I am supposed to keep the water level where I want it?

GreenMan13

Either the inlet or the T will determine the water level. Which one depends on how your inlet is set up.

If the Inlet is set up like in the image with inlet higher then the T then the inlet will determine the water level. When the power goes off the water will drain through the inlet and then lower inside the pipe to the level of the T. You need to make sure the pipes are water tight so water can only get into the pipe through the inlet from the tank though.

If the inlet is lower then the T then the T will determine the water level. This is due to the water level will keep getting siphoned into the pipe till the water level is equal to the T height.

Basically the higher of the two will be the height of the water level. You do want to make sure that if the pipe gets cloged that the amount the sump pumps back into the tank will not over flow the main tank though.

roman

i am interested in making one of these myself for a 180gal/wet/dry tank, i have seen a few vararations of this and i'm wondering what the reason for the vent tube? this has been a very helpful forum

pepetj

Vent tube allows air to go out as water goes down to the sump, through the T section, without braking the siphon. To start it, I just add water with a turkey blaster until it reaches the output T; once that is achieved, I either suck some air (until water comes in) from the air check-valve with my mouth or with a vacuum pump (ToM Aqua Lifter Water and Air pump).

Pepe
Santo Domingo