Overflow Boxes

[PineHill]

What are some good overflow boxes (ie, doesn't lose syphon, quite, reliable) that have a ~600gph.
Also is there a way to reduce the flow rate of an overflow box?
Thanks

[fishsticks]

my overflow box was working on a 110 gallon and I never had issues with it I just used air line tube with the end of a bic pen worked like a charm lol!!! hope this helps

[bitterman]

Flow rates for overflow boxes are rated at max. Actual flow is dependent on your return pump at given head hight.

I don't like using overflow boxes, and must advise getting the tank drilled. If you do go the overflow box route get 2 to have some redundancy, ensure both can handle the full flow of the return pump.

Bruce

[Hookup]

+1 on drilling the tank, which sounds like a huge pain in the you know what, but honestly isn't.  Tearing down the tank for a weekend is not that big of a deal, get some cheap containers, hell you can come borrow some of mine if you like, and about 2 hrs later, everything is out of the tank, the tank is ready to be drilled... then you simply need to glue-in the overflow system, let it cure, and wamo you are back up and running like a champ....

[redbelly]

Agreed, drill the tank!

[PineHill]

Thanks for the fast replies.
I have definitely thought about drilling the tank and I am not too worried about tearing it down because I had planned on doing it this month anyways since I am moving my Africans into it and my Oscars out.
The tank is a 6' 125 gallon.  I'm just as new to drilling a tank as I am to overflow boxes, however I do have one drilled tank  with sump I bought and I have it up and running so I have been inspecting that.
I have done most of my readings on sumps and overflows as oppose to drilling, so how do I go about choosing the bulk head sizes, how many holes and where they should be located on the tank.
Within the next month and a half during the tear down I plan to build a DIY background like the ones on cichlid-forum so I would probably have to consider the drill holes while building that.
Thanks for the help and replies.
Chris

[bitterman]

I'd go with 2 1.5" bulkheads, most are for 2 3/8" to 2 1/2" holes, but check and get your bulkheads before you drill. Snigger has drilled a lot of tanks for me, I highly recommend him!

You need to ensure your tanks glass is Not tempered!!!!!

Bruce

[Hookup]

+1

Or go with 2" downflow pipes. but either way, go with 2 of them... Get your bulkheads at just about any LFS, 1.5" should be less than 20$ each, they are black, but it is PVC... took one to a plumbing store and he tried to sell me ABS to go with it cause the color matched... /sigh..

Snigger drilled about 10 holes for me so far, no issues...  No idea on how to check if your tank is tempered glass or not...

[PineHill]

Ok thanks for the info.  I'm pretty sure only the bottom pane is tempered but how can I tell for sure?  What would be the max flow I would get with those two drill holes assuming I have a pump that could max them out?
Chris

[Hookup]

Not sure on the max flow you can get... but I do have a reason for posting a response...   WHY are you asking?   You do not want maximum flow through your overflows do you?  In the SW world, we want slow-flow through the sump, to get the "sump-stuff" to clean the water completely before returning it to the tank...

The two holes are for security, if one clogs, you do not get a flood, cause we all check our overflow's weekly to ensure they are working and not clogged... (yeah right)

Do you have a reason you are looking at "max-flow" rates?

[FocusFin]

Do you have a reason you are looking at "max-flow" rates?

I  have two 1.5 inch downpipes and with my ballvalve half open it's plenty of flow. I think you want the flow to ripple over the sump/refugium rather than rush, the large pipes are for less chance of obstruction and let's face it, a couple of 3/4 inch pipes coming off a big tank isn't very manly looking 

[Zzippper]

I  have two 1.5 inch downpipes and with my ballvalve half open it's plenty of flow.

Ballvalves on the downpipes??    Not a good idea, my friend. More likely to become obstructed at some point. Your much better off regulating flow by putting the ball valve on the return line.

Or did I understand you wrong...?   

Z

[FocusFin]

Ballvalves on the downpipes??    Not a good idea, my friend. More likely to become obstructed at some point. Your much better off regulating flow by putting the ball valve on the return line.

Or did I understand you wrong...?   

Z

I had it on the return originally but it was a torrent of flow through the sump/refugium, it seemed pointless having a refugium with water rushing that fast over it. In the event of an obstruction my return pump will run dry but there's no chance of a flood. Is there a better way to reduce the flow over the refugium? I'm still new to running a sump so fire away.

I should add that both my overflows have strainers so I'm not sure anything could get through but I suppose it's possible.

[bitterman]

If you look at this pic when Art and I were plumbing  the retun line for my 180, There is also a ball valve above in the pic you can't see.

-Straight up goes to the tank
-The 90 down had a pipe put in it cut long enough it will be belw the water level in the sump,  this is the return to the sump to decrease overall flow for the system, you may need more then 1 of these depending on the pump, in this cas I did, so I had 2, one on the other side that is pump trough my trickle filter to increase filtration. Eventually when adding more tanks, I can hoop upto this feed and drive mroe tanks off it instead.

The lowest ball valve is not really needed, I just added it in cas I wanted to remove the pump and not have any flow bad tto the sump.




Bruce

[RossW]

I had it on the return originally but it was a torrent of flow through the sump/refugium, it seemed pointless having a refugium with water rushing that fast over it. In the event of an obstruction my return pump will run dry but there's no chance of a flood. Is there a better way to reduce the flow over the refugium? I'm still new to running a sump so fire away.

I should add that both my overflows have strainers so I'm not sure anything could get through but I suppose it's possible.

I don't have a sump, so my comment are not based on expereince but... if you restrict the water going to your tank via the return, then the water coming down the down pipe can't exceed the water going up the return.

Also, I seem to recall that pumps can handle back pressure very well but can't handle a lack of water on the inlet.

[FocusFin]

I don't have a sump, so my comment are not based on expereince but... if you restrict the water going to your tank via the return, then the water coming down the down pipe can't exceed the water going up the return.

Also, I seem to recall that pumps can handle back pressure very well but can't handle a lack of water on the inlet.

True, perhaps I need to play with the return valve a little more.

Sorry for the thread jack, back to the original post

[Zzippper]

... if you restrict the water going to your tank via the return, then the water coming down the down pipe can't exceed the water going up the return.

Also, I seem to recall that pumps can handle back pressure very well but can't handle a lack of water on the inlet.

What he said.   

Z