HOB Overflow Dependable Good Flow?

[dhnguyen]

the point of the U in the DIY PVC is so that the surface can be skimmed as well.

[t11t5]

Here is the cheapest place I know for the Pro-Clear. Just scroll down the page in the link and you will find them.
***PRO-CLEAR***

[dermer]

is there a reason it is so large of a U and does it allow for suction to restart if it loses it

[dhnguyen]

Yes the siphon is kept when the power goes out and will restart automatically. Been running mine for 3 months now and through several power outages, this thing never failed to start right back up.

[lavith]

Originally posted by sanosuke
I would recommend the CPR overflows. My friend have one since 2003 and works great in his opinion.

You obviously haven't used one and you would recommend it. That';s like "I hear a story from a friend's friend of my friend"

CPR overflow design is the worst design ever got invented. That is not to say that everyone will have problem with it but it's true to say that most folks will have problem with that CPR overflow design.

In contrast, some ppl might have troubles with U tube overflow design but most will agree they work just fine.

[lavith]

Originally posted by krowleey
im sorry but that DIY overflow with all the pvc is horrible to look at, unless you are Sanford and son. if you dont want to drill your tank, the CPR overflow works fine with the aqua lifter. i used one for years. but now i do nothing have RR tanks. and if you dont want to use a aqualifter yu can simply use a powerhead although it will spit air in your tank no and then. the real solution is drilling the tank, anything else is just a band aid.

Use powerhead to replace aqualifter? Are you alright? Obviously you haven't seen any powerhead spews water through the venturi due to coraline algae grow at the opening of powerhead nozzle. As dhnguyen said, you know nothing about HOB overflow.

[IPT]

Just had a CPR overflow my tank last weekend. Partially my fault. I upgraded my sump return pump and it created some turbulance near the surface skimmer causing air to build up and break the siphon. I'm drilling my new tank as soon as I get the glass for the overflow box. My last tank was drilled and I never would have had this problem. I have had tanl overflows or near ones with the CPR and U tube type overflows of the old days (I remember drilling the top of my U-tubes and sucking the air out every few days). Some people go forever without a problem. Some people also lft heavy things with bad form and never get hurt. To me it's just a risk not worth taking - but that's just for me. I hate mine, and I will not miss it at all once it's gone. Doesn't mean it won't work great for you though.

[RONCGIZMO]

I've been running my PVC overflow since 3/06 and it's been doing a great job... I tested a lot before I trusted it..turning the return pump off then on up to 3 hours or so..I'll never buy another pre-made overflow when this thing can be had for under 5 bucks and 15 min.

[Lost in Tanks]

i had a Lifereef HOB, i never once had a problem out of it, not once did it break suction (at least not without my help) the entire time it was on my tank.

[sjm817]

I've owned CPR, Amiracle, Lifereef. The CPR is a terrible design. If the overflow accumulates air, and is reliant on an external powered device to evacuate the air, it is a very unreliable design. Mine failed twice in 3 months (clogged air nipple).

The Amiracle was very reliable, but did not handle much flow. A Mag5 pretty much maxes it out.

The Lifereef was awesome. It was as reliable as the sun rising and easily flowed 2x the Amiracle.

The PVC overflows are kind of ugly looking IMO, and dont have a surface skimmer, although I'm sure one could be added.

[jener8tionx]

Here is my overflow:



I used acrylic sheet and coppied melev.

Here is all the info:

http://reefnetwork.com/jener8tionx/weblog/3.html

[sjm817]

That is a CPR type overflow, and has the same design and reliability problems. It will accumulate air, and requires a vacuum pump to remove it. Keep an eye on the water level in the C Channel. If you see an air gap in there, fix it or it will soon fail.

[jener8tionx]

The design has absolutly no flaw. Trust me on this. If power cuts out it maintains siphon for hours. If siphon is lost, A is connected to the veturi output of a power head a readily pumps out the air and restarts the siphon. If the powerhead fails, it will still keep siphon and I get very little bubbles in the top.

[sjm817]

A good overflow doesn't have or need a powerhead to pull out air. There should be no need for one. A good overflow will never accumulate any air.

[hllywd]

The problem with that design accumulating air is the large flow capacity. If you aren't close to that capacity it won't wash the air bubbles through like a u-tube does, u-tubes also become unreliable if you have too many for a given flow. In the past I tried "backup" tubes thinking that in case one failed the second would take over, what I found was air accumulating in both until it created flow problems or failed.

IME a single 1" u-tube at ~400gph cannot accumulate air because the flow is to high through the tube.
Additionally any good over the back should hold it's siphon indefinately during a power outage as long as both ends of the overflow are submerged.

Tim

[sjm817]

The difference is, a U Tube with the proper flow (~ 200 GPH+) will not accumulate air. A C Channel unlike a U Tube, is wide and flat. It will always accumulate air. Less flow though it usually is better, but in the end it still does. That is the reason they require an external pump to remove the air accumulation, and why it is a less than reliable design.

[jener8tionx]

I would agree with you if there was a senario in which it would fail. This design although flawed without certain parts like something to draw out excess air, has zero reliability issues. I have tested it by forcing parts to fail and this is perfectly reliable. Please explain how it could ever fail.

[slandis3]

something to consider, Taking an air line from the weir and puttinf in the intake of your return pump. When the power comes on the pump will pull ot the air.

[sjm817]

Originally posted by jener8tionx
I would agree with you if there was a senario in which it would fail. This design although flawed without certain parts like something to draw out excess air, has zero reliability issues. I have tested it by forcing parts to fail and this is perfectly reliable. Please explain how it could ever fail.

There are many many ways it can fail.

It could fail because air builds up in the top of the C Channel and doesnt get drawn out by the pump.
The vacuum pump/powerhead can fail
The air line can clog
The airline can leak
The air nipple in the top of the overflow can clog (this was the problem I had with my CPR). It only takes a tiny speck to clog it.

It doesnt take a power failure for it to fail, and a failure doesn't necessarily mean a total break in siphon cause a flood. If the system is running and air accumulates, the flow slows, the level in the display rises, the level in the sump drops. This is what happened to me. Your ATO will kick in to refill the sump. If you are using Limewater topoff, this can be catastrophic. Luckily, I was not at the time. I am now.

This board is full of posts of people having failures with CPR overflows. Yours is not a CPR, but has the same issues.

Are you saying that CPRs haven't had these problems, or that yours is somehow different in design?

An overflow that does not accumulate air, and needs no external method for removing it is more reliable. That is just a fact, and has been proven many times over. No moving parts, nothing to plug in, nothing to clog.

[colotl]

I made me a pair of these DIY overflows. The are super quiet and always self start the siphon when I turn the power back on.
I lost power yesterday and worried because usaully Im there to see it self start. I came back home and it was up and running!
As for looks I place them flush against the side walls. After a month or so they got covered in coraline and blend in.

[colotl]