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Herbie drain on old 90g RR


Stiffler308

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Hello All,

I am setting up my first marine tank, a 90 gallon reef-ready with a single overflow tower.  There are two holes drilled, a 3/4" and a 1".  I am planning on installing a Herbie drain.  My question is, is it worth drilling the smaller hole larger to match the other drain?  Or would it be fine to have the main siphon as 3/4" and the emergency drain as 1"?  I am planning on having a ~1000 gph return with 1" plumbing.  My preference would be to have all the plumbing the same size, but I am weighing if it is worth the risk of drilling.  Thanks!

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The overflow box is likely designed for the flow rate of the 3/4" return which is good enough for a 90g. Just add in an external 3/4" return and make the current 3/4" the emergency drain. I did this and it works well. Also many 90g have the bottom tempered so be careful. See if there is a small air hole in the durso pipe top. I had to cover the hole in order to keep the air out of the drain to quiet it up. See my build link in my sig.

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Thanks guys!  If I use the 3/4 as the main drain, does the rest of the plumbing (return line) need to be 3/4?

 

The usual is 3/4 return, 1" drain. Why don't you just set it up as a durso and be done with it? This would keep you from having to drill another hole, or adding an over the top return.

 

FWIW, I wouldn't drill any holes close to the originally drilled ones, and as mentioned, some tanks are tempered on the bottom, so if you are set with that idea, double check first!

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I would rather not use a durso due to noise, and I like the redundancy of having an emergency drain.  I don't mind running an over the top return, since it will be covered by the canopy

 

Fair enough. I think the durso would be quieter than most of the other equipment you will end up running on it anyways. I think running over the top return takes away from the safety net of your redundancy in the drain situation.

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I use the 1" on both sides for the drains and the .75" on each side for the emergency with return coming over the top.  I have seen setups that use one of the .75" for the return with the other one used as the emergency. 

 

If you do run over the top I would recommend a wye like this one.  http://www.bulkreefsupply.com/georg-fischer-wye-check-valve.html

 

 

If you are dead set on drilling I think I would drill a return hole in the back for the return.

Edited by Jim Mc
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  • 2 weeks later...

Here is a simple calculator for flow rates of pipes. The rate is going to vary depending on elbows and turns but it will give you a good idea of the kind of flow you should expect in a pipe.

 

http://www.beananimal.com/articles/hydraulics-for-the-aquarist.aspx

 

Example:

 

The calculation for a 3/4" ID pipe full siphon with no change in direction with a 30" drop with a submerged discharge is 1048gph and with a 36" drop it increases to 1148gph or a 100gph increase

 

 

The calculation for a 1" ID pipe full siphon with no change in direction with a 30" drop with a submerged discharge is 1863gph and with a 36" drop it increases to 2041gph or 178gph increase

Edited by tom39
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  • 3 weeks later...

Fair enough. I think the durso would be quieter than most of the other equipment you will end up running on it anyways. I think running over the top return takes away from the safety net of your redundancy in the drain situation.

 

 

Can you expand on your last statement, just curious to your logic here.

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He means a pipe outside the footprint of your tank/sump that leaks will leak to the floor.... versus a leak that leaks to your sump.

 

I have a 90 with a herbie. The return comes over the back. I had stock plumbing already installed, so I left the durso on the emergency and cut the stock return below the durso so that's my primary drain now. I have a full siphon in the primary, but the durso carries a bit of water. If the primary ever failed, the durso on the emergency drain could still handle all the flow.

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As others have mentioned, stick with the 3/4" as the main and 1" as the emergency. The 3/4" duly open at siphon will handle almost 1,000 gph. If you have a 1,000 gph return pump, it will flow a lot less than that after head loss. Oversize the return plumbing to reduce head loss (e.g. if the return pump has a 3/4" outlet, use a bushel to increase to 1" for a majority of the run then reduce back to 3/4" into the tank). IMO, the main advantage of using the 1" drain as the emergency is that it adds an extra safety net in case the main gets clogged. With a herbie, you will need to have a trickle going down the emergency to keep a steady water level. That "trickle" uses up some of the flow capacity of the emergency drain, so if the main and emergency were the same size (and the main siphon were fully open), you run the risk of flooding if the main were to get fully clogged. This is where the bean animal was invented to have an extra emergency drain to account for this. So in summary, 3/4" main, 1" emergency, oversize the return, all the plumbing does not need to be the same size.

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I have found that the herbie's are not needed as they were 'designed' to attempt to solve noisy/splashy sumps. The standard durso works great if you valve the return and drain and use some sort of bubble trap/drain box/bag filter in the sump.

The chances of a clogged drain are minimal at best provided you use the standard durso intake screens.

In 22 years of maintenance on hundreds of tanks, I have only encountered 2 clogged drains which resulted in a flood.

Durso's can be made to run dead silent if you know how to plumb them.

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