HOB Overflow or try drilling the tank?

[novahobbies]

OK, I have an issue I'm batting around. I'm going to upgrade my aunt's tank and plumb it for a sump. I've only ever had experience with reef-ready overflows, but her tank is a standard non-drilled 90 gallon aquarium. Right now she's using a Skilter, a HOB protein skimmer, a couple Koralia-Ones, and that's about it. If she OKs it, I'm going to upgrade her to a 30 gallon sump, relocate the skimmer to an in-sump function, add a pair of Koralia-threes while keeping the smaller ones, and build her a small refugium in the sump to help her nitrate levels. I'm trying to make this project as simple as possible. My aunt is one of those people who loves to look at her tank, but doesn't always follow through with maintaining the tank. Right now all her water changes and replacements have to go through the top of the tank, which for a short woman can be a pain.....hence the beauty of the sump.
So here's my problem: how should I go about getting the water down to the sump? I was set on using a HOB siphon style overflow with an aqualifter pump to restart the siphon in case of power outage, but now I'm second guessing myself. I was considering drilling the tank for a home-made overflow instead.
Can anyone chime in and tell me how easy/difficult it is to drill for a custom overflow? I have the material around the house to build an overflow box, but I've never done anything like this, so opinions/thoughts/how-to website links would be of infinite help here! I can see some immediate benefits if I go this route: (1) never having to worry about siphon-caused flooding, and (2) money saved to be used for live rock or fish!
I'm not even sure if the glass is safe to drill. If I remember correctly when we bought it, the tank is an allglass / aqueon brand tank, standard 90 gallon glass box. I would need the back drilled only, so I'm thinking the glass should be non-tempered back there. What do you guys think?

 

[snakeblitz33]

you should look up some stats on 90gallon aqueon tanks first. I believe that they are all or almost all tempered on the bottom. It would be easy to put in a 2" bulkhead on the side of the tank and fit it with a 2" pvc overflow.
Then again, research risk. I'm pretty sure it would be more responsible for buying a new 90gallon tank with an already pre-made internal overflow box then to risk drilling your current one.
Anyways, that's just my $0.02.

 

[kube]

use a u-style over flow, i just set up my first sump and went with the u style and it works great and never looses siphon when the power is out

 

[natclanwy]

It's kind of a toss up since the tank is set up already, a drilled tank is the best since they are the most reliable but it is some what difficult to drill the tank especially with livestock in it, and you risk breaking the tank which would be an expensive mistake. HOB style overflows are slightly less reliable but much simpler to install on an existing setup, the key to setting up a reliable HOB overflow is selecting the correct size pump and checking your U-tube and pump for proper operation on a regular basis.

 

[pumper]

Don't waste money on a hob because they are a pos.... Drill the tank and you will have no problems....

 

[natclanwy]

Originally Posted by Pumper
http:///forum/post/2782029
Don't waste money on a hob because they are a pos.... Drill the tank and you will have no problems....
If setup and maintained correctly they are just as reliable as a drilled tank I have had mine running for 4 years with no issues.

 

[stanlalee]

Originally Posted by Pumper
http:///forum/post/2782029
Don't waste money on a hob because they are a pos.... Drill the tank and you will have no problems....
well designed U tube hang on backs work flawlessly year after year. I dont know what kind of problems you are referring to.

 

[novahobbies]

OK, you say "well designed" u-tube HOBs....can you give me an idea of whose you consider to be well designed?

 

[kube]

i've been using an e-hopps u tube style and turn off the return pump every other day to feed and have never had it not keep its syphon and start right away. What kind of problems are you refering to?

 

[natclanwy]

Originally Posted by novahobbies
http:///forum/post/2782164
OK, you say "well designed" u-tube HOBs....can you give me an idea of whose you consider to be well designed?
Pretty much all U-tube overflows are the same basic design so you can use whichever one you find or afford. The only thing you might watch for is the baffle in the outside box I was discussing this with Dennis210 and he said that some of the older overflows did not have a baffle in the outside box to keep the end of the U-tube submersed, but that is easily remidied with a stand pipe in the box. A well designed U-tube overflow refers more to the system as a whole ie Overflow, Plumbing, and return pump. Sizing the return pump being the most critical.
The E-shopps overflows are probably the least expensive and will work fine.

 

[stanlalee]

Originally Posted by novahobbies
http:///forum/post/2782164
OK, you say "well designed" u-tube HOBs....can you give me an idea of whose you consider to be well designed?
any of them that the U tube sticks far enough into the box to not break the siphon (that would be basically all). the two I have used (and am still using) have been $39 egay boxes. havent had a single issue and have never broke siphon once when the power goes out or I cut the return pump to do maintenence.

 

[novahobbies]

Well I think I'm starting to narrow my thoughts down. I really would prefer to drill the tank, but the more I think about it, the less inclined I am to try it. It's not my tank, after all, and even though I'm 99.9% sure the back glass is drillable......well, like I said: It's not my tank. I don't feel like replacing a 90 gallon tank, fish, etc if I foul it up.
Before I started asking online, I was looking at a cpr-style I found for 30 bucks. It had a black plastic top to impede algae, and a port for an aqua-lifter to remove trapped air. It "claimed" that in the event of a power outage, the siphon would break and stop, but would automatically re-start with the aqualifter rebuilding the siphon when the power went back on. The physics made sense, but I've seen that people have had problems with this style of overflow.
Now I see you all are talking about the u-tube style overflows. I went and found the ehop style. Price is similar to what I was looking for, but for the life of me I don't see how it would automatically restart after a power outage.

I'm no genius, so I'm sure I'm missing something here. Seems like this would happen: Power goes out, so the return pump stops working. The siphon tube continues to drain the inner overflow box until the water level drops below the flow teeth. No fear of draining the whole tank, of course. But the siphon tube would continue to drain the water from the inside of the box until it sucked air, right? So now there's air in the Utube....when the power goes back on and the water fills the main tank, how will the siphon restart? There's no force to push water into the utube, so.......? what?
LOL Like I said, I feel like I'm missing a critical ingredient here!!

I know my Aunt and her luck, and I just know if something is going to go wrong, she'll be calling me in a panic at 4 in the morning. I'm really hoping to avoid that! The CPR seemed pretty foolproof with the addition of the aqualifter or venturi powerhead, but if there are a lot of bad experiences, it's gonna steer me away for sure.

 

[natclanwy]

Its kind of ironic that the aqualifter that is supposed to make the CPR foolproof is one of top causes for failure on that overflow.
Okay lets see if I can describe this well enough without a diagram. A U-tube overflow has a baffle in the box outside the tank that keeps the water from completely draining out of the outside box similar to the baffles in a sump that seperate each compartment. When the overflow is running the water comes through the u-tube into the chamber after the chamber fills it overflows into the second chamber where the drain is and continue down to the sump via the drain. When you lose power the water will drain completely out of the second chamber but will leave the first chamber full keeping the end of the u-tube submerged. The water in the DT will drain down to the bottom of the teeth and then the inside box will drain until the water level is equal in the inside box and the first chamber of the outside box keeping both ends of the u-tube submersed in water preventing air from being pulled into the u-tube. When the pump resumes it will fill the DT overflow into the inside overflow box raising the level and the siphon will equalize the water level and start flowing into the first chamber now your siphon is restarted. Actually the siphon never stopped just the flow, with the CPR oveflows they often will lose their siphon completely during a power outage wihich is the reason they require the aqualifter pump.
Hopefully I explained this well enough it is a very simple concept but very difficult to explain pictures or video would be so much easier.

 

[pumper]

Drilling a hole is foolproof. Its similar to drilling masonry. Here is a video of how to: http://www.youtube.com/watch?v=zwc3o...eature=related
Drill the tank, hobs are unsightly.

 

[stanlalee]

Dont get me wrong, drilling is prefered but its also harder and easier to mess up. we have LFS that offer to do it. do you know if the glass is tempered or not? HOB are a pain to start the siphon for (expect to taste salty tank water until you get the hang of it) but otherwise problem free and most importantly tranferrable and/or sellable when your done.

 

[kube]

Originally Posted by novahobbies
http:///forum/post/2782700
Well I think I'm starting to narrow my thoughts down. I really would prefer to drill the tank, but the more I think about it, the less inclined I am to try it. It's not my tank, after all, and even though I'm 99.9% sure the back glass is drillable......well, like I said: It's not my tank. I don't feel like replacing a 90 gallon tank, fish, etc if I foul it up.
Before I started asking online, I was looking at a cpr-style I found for 30 bucks. It had a black plastic top to impede algae, and a port for an aqua-lifter to remove trapped air. It "claimed" that in the event of a power outage, the siphon would break and stop, but would automatically re-start with the aqualifter rebuilding the siphon when the power went back on. The physics made sense, but I've seen that people have had problems with this style of overflow.
Now I see you all are talking about the u-tube style overflows. I went and found the ehop style. Price is similar to what I was looking for, but for the life of me I don't see how it would automatically restart after a power outage.

I'm no genius, so I'm sure I'm missing something here. Seems like this would happen: Power goes out, so the return pump stops working. The siphon tube continues to drain the inner overflow box until the water level drops below the flow teeth. No fear of draining the whole tank, of course. But the siphon tube would continue to drain the water from the inside of the box until it sucked air, right? So now there's air in the Utube....when the power goes back on and the water fills the main tank, how will the siphon restart? There's no force to push water into the utube, so.......? what?
They highlighted part is where you are missing it, the inner overflow does not drain completely, only about 3/4 leaving the u-tube in the water always, the reason this is , i think, is because there is not enough weight of water above the bottom of the u-tube to push it up the u-tube, but once the power comes on water starts overflowing back into the box and there's enough gravity pushing the water down and back up the u-tube, works flawlessly. I just set mine up about a month ago, i did test runs in the garage with Rubbermaid tubs, and pvc pieces and just didn't glue anything until testing was done.
LOL Like I said, I feel like I'm missing a critical ingredient here!!

I know my Aunt and her luck, and I just know if something is going to go wrong, she'll be calling me in a panic at 4 in the morning. I'm really hoping to avoid that! The CPR seemed pretty foolproof with the addition of the aqualifter or venturi powerhead, but if there are a lot of bad experiences, it's gonna steer me away for sure.

 

[novahobbies]

OK, I think the principle of the non-breaking siphon has been explained -- thanks to both of you who helped clear this poor person's head! To quote the Packled: ""We are smart now..."
Pumper, if this was my tank, or even if it was hers still but empty, I would drill in a heartbeat...I still like the look of the drilled overflow so much better. But, God forbid, if I was to try and drill,

[hr]
it up and break her tank, I would be owing a LOT of money. I don't need that stress!

The tank is a all-glass/aqueon 90 gallon, so it *should* only be tempered on the bottom. I read the aqueon literature, saw the .pdf file on the stats, and everything says it is only tempered on the bottom. But, ya know what? Nowhere did I see a statement saying "100% guaranteed non-tempered side glass!" With that in mind, I may just go the safer route....but I'll also give her the option in case she's willing to risk it!!

 

[adurost]

Originally Posted by Kube
http:///forum/post/2781989
use a u-style over flow, i just set up my first sump and went with the u style and it works great and never looses siphon when the power is out
I am trying to get my new-to-me 90 gal tank set up... I have a HOB overflow with 2 U-tubes, a trickle filter w/bio balls, and a Rio 2100 powering the return (694 gal/hr) from the sump.
1st problem: I can get the siphon started, however, I've only been able to fully remove the air from one U-tube; when I attempt to fully remove the air from the 2nd U-tube I end up losing the siphon on the other one (ends up pulling too much water and breaking the seal).
2nd problem: When I turn off the return pump and allow it to back siphon to the sump (to check water levels) I loose the siphon in the U-tubes/overflow. I just narrowly escaped an overflow of my DT this afternoon! The DT water level is within 1/2" of the top of the tank, but the sump level is only about 1/3 full when operating, and there is only 1/4" to 1/2" of water above the return pump intake. The water level in the intank portion of the overflow box is about 1 1/2" below the water level in the DT. The HOB overflow has an inner chamber and dual lines out.
The books and you all here on the forum make it sound so easy... What am I doing wrong??

 

[mkroher]

drill the tank. you'll sleep better.
i'm on the 3rd floor apartment. I'm going to drill my 90 because I don't want ANY chance of losing syphon. No one on Earth can talk me out of drilling my tank.
I bought the kit from glass-holes.com. It came in 3 days. The guys at glass-holes are really nice and they even threw some candy in with the package *nom nom nom*.
drill it!