corner overflows

[greatgman]

ne1 know if you can install corner flows on a non drilled bottom tank
(drill the back low)
does ne1 know where u can get the kits for that kind of thing?

[seaham358]

As long as the tank glass is not tempered it can be drilled. Why would you drill it low in the back? closed loop or for a sump or wet/dry?

http://www.premiumaquatics.com/Merch...Code=Bulkheads

I run 1" bulkheads in both my tanks and they work well, remember a 1" BH needs a 1 3/4 hole drilled in the tank.

[runway1]

What about flow rate? Problem with back drilled pickups is the flow rate will be significantly less than a bottom drilled with a box. Elbow and that gravity thing just kills the flow rate.

[seaham358]

This is not true, if you use an elbow on the inside of the tank and have it skim off the surface and in the water you will get great flow down to the sump. Doing it this way also allows you to have the water level higher .
Will having a drilled bottom be better, probably.. But when you alread have a tank why get a new one just to have the bottom drilled.. And having it drilled IMO is much better the an overflow box and cheaper.
Not sure what a gravity thing is?????

[BillyZ]

"most" glass tanks only have the bottom pane tempered. If your tank isn't already drilled in the bottom, do NOT drill the bottom. "some" tanks have all tempered glass. If this is the case you should not attempt to drill your tank. 99% of the time tempered glass will shatter when trying to drill. If it's not tempered and you're brave enough to drill it yourself, do some searching here and on the web, there are lots of tutorials. You'll need a quality glass hole-cutter drill bit; a variable speed drill; water for keeping the drill and glass cool; and lots of patience! Don't try rushing it! And do NOT try drilling a tank with water in it!

[runway1]

If you have an elbow you'll significantly reduce the flow rate. That's just a law of basic fluid dynamics, not my opinion.

As for gravity well, fluid flowing down uses it to go faster. Fluid moving sidways (redirected by the elbow) can't use this force.

A 1.5" hole supplied by gravity flow will flow about 600 gpm, max. If you eblow out, travel about 6" and then elbow back down, I would expect about a 25-30% decrease in flow rate. Thems just the facts.

[seaham358]

I'm not going to argue about it... I know what works well for me and a lot of others that I know. IMO I would rather deal with a little less flow then a flood caused by a overflow box.
If I set up a new tank I would go with 1.5" bulkheads for more flow, I have 1" now and IMO have very good flow for my 125 reef and 55 fowlr.
And drilling a tank is cheaper then buying a new tank just to have the hole in the bottom to pick up a few more GPH.

[runway1]

Absolutely, seaham. Depending on the individual scenario, there are many reasons to go with back drill. I certainly wouldn't buy a new tank just for a bottom hole.

As for flooding, I don't get it. An overflow box with a bottom drill will only siphon out until the water level falls below the "teeth" on the box. Then it will break and stop flowing. If your sump is big enough (and it should be to avoid this) then you have no worries of flooding.

[seaham358]

Flooding with hang on back overflows... if syphon breaks during an outage and the power comes back on the water ends up on the floor. I have never had this problem but know other reefers who have and they said they would never use a OF box again. what your talking about where Im from is not called a over flow box, there called reef ready tanks that have corner overflows not a box.. The box hangs on the back and looks like a box..

[runway1]

Not clicking with me, seaham. I mimick a power outage every week when I do water changes......

When I siphon water out into the sink (like when the power dies and water is siphoned into the sump - assume sump has room to hold excess, which it should)....the HOB-OF box stops siphoning, correct?

Ok...sump is almost overflowing and HOB-OF box has stopped flowing because water level dropped - we're here now and it's just like my water change (assume the sump is full)

I habd fill my tank from water jugs which is exactly like.....Power comes back on ......pump returns from sump into main tank, right?.....Ok, tank water reaches "teeth" on HOB-OF box and bada-bing Siphon restarts and all is back on track because.....

The siphon itself (U-tube) never took air. It's always primed and ready for the water level to return. I do it once a week. Try it.

The folks you're speaking to may have set up such that that siphon actually "breaks" and takes air. Then yes, it will flood. if set up correctly, it doesn't do that. hope that makes sense.