# DIY wet/dry



## cp5041 (Oct 29, 2006)

I'm building my own wet/dry filter and I've had an one before but it kept overflowing my tank. I have a 55 gallon glass aquarium so I have to use an overflow. My question is how should I choose both the overflow box and the return pump without running the risk of overflowing the tank or sump. Or sucking the sump dry??????


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## trreherd (Aug 7, 2006)

I think a single bulkhead will drain 600 gallons an hour so you should get a pump that does about that-I think if you pump is not pumping fast enuff and your sump is overflowing you can use a ball valve to slow the flow so the pump can keep up


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## porksnorkel (Oct 6, 2006)

gotta have a ball valve on the intake side anyways in case u lose power or the pump seizes or something like that. 55g of water makes a very big mess.


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## fish_4_all (Nov 13, 2006)

Agreed, best solution is a check valve for the sump, when it gets to apoint the valve can either slow or stop the flow and the pumps can catch up, it could also be rigged so that it increases flow when needed.


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## caferacermike (Oct 3, 2006)

Y'all are not thinking correctly.

It doesn't matter what size the return pump is as long as it is not rated MORE than the overflow box. You do not need any checkvalves or ball valves.

I'm a pipe fitter, trust me on this one.

Run your overflow box wide open to the wet dry. You might want to run it in one size larger pipe, as in, if your bulkhead is 1" upsize your pipe to 1 1/4". It will run quieter. Typically you will run your return line about half your suction line. Where your return line bends back over the tank drill a small hole in the elbow just under the water line. 

Now I want you to think about something. Your overflow box can ONLY work as fast as your return pump replaces the water. Period. Your water line in your tank will be dictated by the heigth of the overflow teeth. If your pump quits working it quits putting water back in the tank. You will only siphon about another 1/4" of tank water before the teeth are ABOVE the waterline. No magic happens here. One the teeth are above the waterline no more water can magically end up on the floor. It will not continue sucking 600g of water out of your tank. However, that hole you drilled in your return 90 will break suction just as soon as it is exposed to air. Generally as soon as the overflow box loses suction the return bend 90 also breaks suction. Of course this amount can vary due to placement of the hole. Drilling the hole will break any back siphon when it is exposed. Of course you may need to tinker with it a few times to adjust everything. Never just set it up and walk away, thinking it will work. Test it several times by unplugging the kit. Keep in mind that 99% of the overflow boxes will hold their suction in the tubing. So as soon as power is restored the pump will refill the tank to the appropriate heigth, at this point the cycle will begin anew. If for some reason after installing everythign you decide your return pump is to large you can add a ball valve on teh RETURN side to slow it down. Never add the valves to the suction side as it can cause a pump to run dry.

Let's review.

A properly set up overflow will only back siphon about a total of 1/2" of tank water from the display (for insurance purposes when I choose my sump I multiply my tanks lengthxwidth by whatever I need my sumps depth+2". The 2" is equuivalent to 2" of my tank draining back). Thereby your animals will not be in a dry tank. Your sump will increase about 4" in depth. If chosen wisely this is not a problem. If not chosen correctly (as in to small) you will end up with a few gallons on the floor. When the pump restarts it will fill the tank back up tothe overflow line and the cycle will restart.


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## porksnorkel (Oct 6, 2006)

good post mike. now forgive my ignorance, but is it possible that not everyone has the overflow wall in their tank? just a pipe sucking from the bottom? this woulod of course drain the entire tank via gravity, in the event of pump failure. also i'm wondering what would happen if the seal on an overflow wall failed and is this common? would it be good insurance for someone who isn't confident in their set up to just add a check ball in the suction side?

another question...if u drill a hole in the pressure side of the system at the elbow, won't water be forced out of that hole and all over the nearest wall?


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## caferacermike (Oct 3, 2006)

Drill the hole so it points down in the tank...Simple enough.

I don't know anyone silly enough to run a suction tube for a wetdry to the bottom of their tank. If so, bully for them, they get what they deserve. Anyone using only a utube for suction is just asking for problems, check valve or no. There is no one way to make them equal out. Just spend the $50 for an overflow box. BTW, I never once mentioned in my reply that this was advice for an internal overflow. My advice was for a HOT overflow. If for any reason someone was to attempt using only a Utube for suction then it should be cut no more than 1" below the surface and or at least have a hole drilled in it near the surface so that when exposed it breaks the siphon. However, when the pump kicks back on, NOTHING will restart the suction and your sump will overfill your tank causing serious damage to surrounding areas.

Your other question, if a seal should fail in a built in overflow. I've had this happen. Just like anything else, when enough water leaks out it cannot overflow the teeth, thereby ending the troubles. However your sump will dry and you could eat your pump.

Check valves are not adised by myself in your basic wet/dry set up. they fail. To many people would bet the farm on them and anything could cause it not to close properly. Also good luck finding one that would not be a serious restriction in the assembly. I install 12" backflows weekly. I'm pretty familar with check valves. If you could find a PVC swing check that is gravity fed you might have a decent product but I haven't seen any good ones. Spring checks are the only "sure fire" check valve.

A properly set up system needs only a 3/32 hole drilled just below the water line to break a back siphon.


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## fish_4_all (Nov 13, 2006)

Makes sense to me, in words, but for those of us that are not "piping" inclined, :wink: , is there a diagram inline to look at this setup? It all sounds pretty simple and the safeties you explained are actually kinda cool. I always thought the intake tube was deep in the tank in order to remove the debris from the bottom and create circulation.


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## porksnorkel (Oct 6, 2006)

i thought that too, fish...that the intake should be near the bottom of the tank to collect as much schmootz as possible. i had heard of drilling the intake at the top but i forgot to do that. unfortunately i just bit the bullet on that one. my cascade's seal failed and i have a lovely mess to contend w/ tommorrow. 3 tanks have to be drained and moved. i only lost a few gallons so it coulda been alot worse. i have just made my case for HOB's though. the cascade canister will find itself in the trash on thursday! now if u'll excuse me i have to go an order a new emperor HOB!


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## caferacermike (Oct 3, 2006)

Canister filters are another thing. This was all about wet dry filters and sumps, not canisters. A canister filter should not be able to drain a tank. They are sealed units. But if you left it open.......Or removed it for cleaning but did not shut the valves for cleaning and just left the tubing dangling.........


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## usmc121581 (Jul 31, 2006)

> gotta have a ball valve on the intake side anyways in case u lose power or the pump seizes or something like that. 55g of water


I had mony times that I would leave to go to the store come back and there is 30 gals of water on the floor. So to save the power going out problem(which Happens once a week) I bought a $200 battery back up.It last with just the sump pump close to 52 hours. Its a good investment if you do not have a reef ready.


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## caferacermike (Oct 3, 2006)

My 125 is not reef ready. It has 2 HOT 1,200GPH overflows. Each is piped with 1 1/2" PVC, that's 4 total. I live in a neighborhood that is about 100 years old, my house is just a little under that. We lose power about once a month but in 2 years, I've never once had water on my floor.


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## usmc121581 (Jul 31, 2006)

Its the military housing the pump would stop and the siphon on the over flow would break and never start back when the power came back on. So I just bought the battery backup to never have to worry about it again.


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## fish_4_all (Nov 13, 2006)

The sump, if it is big enough will hold the extra if the power goes out. The safeties in place with either a short intake or the hole drilled will prevent the syphoning of 3/4 of the tank. Only a gallon or two can come back out and the sump should have enough room to handle 1 more gallon than you expect to be able to come out if anything happens. 

The battery backup will work assuming that nothing happens to the prop and the pump stops without losing power. 

I thought that there was a ton of things you had to do to make a system safe and prevent water disasters but Mike's idea and setup eliminates all of them that I can come up with. 

One could even setup a ready made tank for an overflow by siliconing glass around the tank about 1 inch wide all the way around except where the overflow for the sump will be. I have seen this done although I have not been able to find instructions to do it. 

Whatever you do, the right safeties eliminates the worry and the right size sump filled to an appropriate level will handle any backflow that might occur if the power goes our or the pump stops. 

I do not however have a solution for the suction loss. I don't know what is normally used to feed the water back in so I can't say.


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## fish_4_all (Nov 13, 2006)

I do have a question that might help to clarify things a little. I thought a sump and wet/dry setup was designed so that the water used a "waterfall to get to the sump. If this si the case, where is the issue with suction? If not, I assume that you are talking about a standard pipe that hangs into the aquarium and sucks water out in which case suction would be an issue. 

It seems to me like the first option is the easiest and have the most safety build right into it. I know some have talked about cutting the tank but the siliconed glass can do the same thing for those that don't want to cut the tank they spent a couple hundred $ on. 

cp5041, didn't mean to hijack the thread.


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## caferacermike (Oct 3, 2006)

F4A, Yes I was referrign to the "waterfall" type HOT overflow boxes. Porks mentioned using a single tube all the way to the bottom of the tank. I don't know anybody that has ever ran one that way. USMC brings up another point, what if your overflow's utubes lose their siphon while the power is out? See the Utubes will still hold water while the power is off and then when the water line rises after power is restored, it will automatically renew itself. But if your Utubes break siphon your pump will overflow the non draining tank. I've only heard of that happening very rarely. The idea of a UPS to drive the pump so the tubes never lose siphon is a good idea. I'd think $60 for a different overflow box would be more reliable and cheaper though.


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## cp5041 (Oct 29, 2006)

thanks for the info guys. i think im goin to go with a mag 5 pump, im a little indecisive if i should use the mag 5 or one of the quiet one pumps. i hear good things of both of them.


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## caferacermike (Oct 3, 2006)

Eheim. 

Mags are well, mags. Not very efficient and kinda loud. Mags are made int he US, Eheims are made in Germany. Think, Ford vs Porsche. They both get the job done but one is way more refined and luxurious.


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