HOB Overflows

[austx]

I've been looking into HOB Overflows for a couple months now and have had several recommendations such as the cpr, rapid pro and reef octopus to name a few. I am interested in the CPR CS102 Overflow box. It has dual 1" bulkhead outflows that run 1200gph, I am interested in the dual outflows for the safety feature of potentially having one tube clog by chance I would still have the other drain working properly. I have a 75g tank currently running a Fluval 405 canister filter and have really wanted to get out of that into a sump but not wanting to rush into the purchase.

My first dislike of the HOB overflow boxes was the loss of power tends to lead to flooding. I was looking at the aqualifter pump and did not know if this could be left running on the cpr unit itself for extended amounts of time, or ideally if I go out of town as a safety feature as well. My thoughts are if it was left on the CPR unit and power went out and came back on that the return pump from the sump would start up and the aqualifter would in turn prime the overflow (if lost) preventing the flooding issue. There may be some other preventable measure to stop the sump from being emptied into the tank that I have not found or thought of too so if you had any suggestions please let me know!

I have also considered a diy type with pvc I believe its referred to as the durso standpipe setup. Ideally this would be in a reef ready tank but wasn’t sure on the practicalities of the use as an hob overflow though. I have not researched this idea as extensively but I am open to the idea still even if someone would be willing to help build the unit that could teach me. I found an interesting thread posted on arc in the past and the design midway down the first page caught my eye (posted by DaJMasta). Thought this could work out fairly well and even talked to a fellow reefer at the office who recommended this method. http://www.austinreefclub.com/topic/10272-diy-overflows/page__hl__%2Bhob+%2Boverflow__fromsearch__1. I'm not sure how often these designs would lose their siphon or if there would be an issue with surface skimming when using a tunze wavebox. If this design does lose its siphon how would you prevent the return from the sump from flooding the display tank after a power outage as well?

If anyone has any ideas, helpful tips, experience with other issues or concerns please let me know. It seems my main concerns with the switch are loss of siphon and flooding due to power outages. I know there is much more I can learn still before making the switch; however, I have limited time in the afternoons to research the topic and would greatly appreciate any help!

Edited December 23, 2011 by bchap

[+mcallahan]

I outlined my concerns here: http://www.MrSaltWaterTank.com/3-pieces-of-equipment-you-should-never-use/

I've known several people who had their HOB overflows setup with the aqua lifter (including by some "professional" tank main't people) and they all experienced a flood at some point.

If you had to mod a piece of equipment to make it work correctly from the start, clearly there is something wrong with that piece of equipment.

Imagine buying a new car and the salesman says, "ok, here if your new car! Now to make it run you have bang on the hood twice, turn the key a certain way and add this ADD-ON piece of equipment to make it work correctly"

If someone said that to me, I'd RUN.

[+mcallahan]

I'd either get a drilled reef-ready tank or have your tank drilled. Nothing beats doing things right.

[nemirn]

Drill it and sleep easy.

[Timfish]

What Callahan and Nemirn said. Internal overflows are much more problem free and if designed/setup right are very quiet. You also do not need to have huge turnover rates between your refugium/sump and your tank. I have systems that have run for years with just a few turnovers per hour.

[pbnj]

Lifereef makes great overflow boxes that don't require an Aqua Lifter pump. I've have one on my 135g for over a year. Before that, I had a CPR on my 75g for about 2.5 years, but the Lifereef is much better.

By the way, I never had a flood in 3.5 years. It's all in the design. When I had my 75g, I had a float switch that would shut the return pump off in case of a siphon failure. In my current 135g, there's enough empty space in the display tank to hold the water from the sump in case of failure.

Internal overflows are not 100% either. Bulkheads can crack/leak, drain pipes can clog, yada-yada-yada. Are they more reliable? Yeah, probably. And, while unlikely, I don't think anyone is going to give you any 100% guarantees that your glass won't crack during drilling.

In the end, whatever makes you sleep best is the way to go.

[austx]

I outlined my concerns here: http://www.MrSaltWat...ould-never-use/

I've known several people who had their HOB overflows setup with the aqua lifter (including by some "professional" tank main't people) and they all experienced a flood at some point.

If you had to mod a piece of equipment to make it work correctly from the start, clearly there is something wrong with that piece of equipment.

Imagine buying a new car and the salesman says, "ok, here if your new car! Now to make it run you have bang on the hood twice, turn the key a certain way and add this ADD-ON piece of equipment to make it work correctly"

If someone said that to me, I'd RUN.

I had actually looked this article over before and was excited to know that I was at least doing one thing right by using ro/di from the beginning haha. Although I would have immediately had my tank drilled at the time of purchase I did not know anyone who could help out and highly doubt it could be done while the tank is up and running currently. So my next ditch effort is going to be the overflow setups. As awful as it sounds I do believe this to be my best alternative and this will at least trade one problem out for the other and be much more efficient for the tank in my opinion.

Lifereef makes great overflow boxes that don't require an Aqua Lifter pump. I've have one on my 135g for over a year. Before that, I had a CPR on my 75g for about 2.5 years, but the Lifereef is much better.

By the way, I never had a flood in 3.5 years. It's all in the design. When I had my 75g, I had a float switch that would shut the return pump off in case of a siphon failure. In my current 135g, there's enough empty space in the display tank to hold the water from the sump in case of failure.

Internal overflows are not 100% either. Bulkheads can crack/leak, drain pipes can clog, yada-yada-yada. Are they more reliable? Yeah, probably. And, while unlikely, I don't think anyone is going to give you any 100% guarantees that your glass won't crack during drilling.

In the end, whatever makes you sleep best is the way to go.

Thank you for the encouraging reply pbnj, I was hoping to get some positive feedback as well. I had thought about the float switch idea as a fail safe to prevent the flooding issue but don’t have much expertise in that area so I may be looking to pick your knowledge on that subject. My co-worker I was talking with had mentioned an osmo-regulator but I believe that may be more for an ato type setup and I just didn’t explain my situation properly. I appreciate the alternative overflow suggestion and will look into the Lifereef overflows and compare the different setups.

Does anyone have any pros or cons for the durso standpipes as they apply to the hob setup? It would be cheaper for sure but I would rather have the best possible setup done once compared to messing around and wasting time and money on frivolous efforts. I appreciate all the help and everyone have a Merry Christmas!