Overflow hole size??

[JoJo]

once again i have removed the tank from the hole to remeasure the overflow holes. i'm trying to make sure that it's possible to have a hole made bigger? I have enough room in the overflow section to have the holes widen to 2 3/8". which would give me 1 1/2" bulkheads & would flow 1800gph, this may be too big since my return pump is a Mag 9.5(3/4" outlet). but i cant find 1 1/4" bulkheads, which i would prefer.

[cracker]

JoJo, I "understand " you can cut larger holes. You need a stand of sorts to hold the drill & bit as stable as possible. You may want to ask at a glass shop. 1.5 " drains would be nice in case a bigger pump is in the future.

[JoJo]

Thanks buddy. does the area inside the overflow need to be enlarged as well to hold more water since the bulkheads will be bigger? i wasnt sure if there was a calculation of bulkhead size to overflow dimensions.

[tbittner]

I use 1 1/4" bulkheads within my sump setup. I bought them at Tractor Supply. MarineDepot sells bulkheads of all sizes so you could also order from them.

A bigger skimmer box will provide better surface skimming. In other words, more of the water going to the sump will come from the surface water of your display tank. This is a good thing because it gets the dirtiest water to your skimmer.

Having a drain that drains more water then the pump can return isn't a bad thing. You wouldn't need to throttle the pump then. It will just drain as fast as the pump can pump it in to the tank.

I agree with cracker, if you're going to go through the trouble of drilling the hole out bigger, then I would go with the 1 1/2" bulkhead size so if you decide you want more flow through the sump, you can just add a bigger pump.

[JoJo]

hey Terry, when i looked up 1 1/4" bulkheads on Marinedepot, they only had 1" & 1 1/2". But cracker is right about going bigger just in case.

A bigger skimmer box will provide better surface skimming. In other words, more of the water going to the sump will come from the surface water of your display tank. This is a good thing because it gets the dirtiest water to your skimmer

since the only way the water goes through the box is at the top, wouldnt it be all surface water going into the sump or am i missing something?

[tbittner]

Example:

#1
Your skimmer box is 12x4 inches.
You want to flow 1800 gph.
The water level would probably be above the teeth in order to keep that much flow going through the overflow box.

#2
Your skimmer box is 24x4 inches.
You want to flow 1800 gph.
The water level may just be above the bottom of the teeth because it doesn't take near the depth of water to get that much flow because there is more surface area for the water to flow from.

As far as the 1 1/4" bulkheads, here is just one place that I found that has them. There are lots of places you could order them from if you want to use this size bulkhead.
Inexpensive Bulkhead Fittings, 1/2"

[JoJo]

i got you terry, makes sense. my box is only 8x6", is this likely to cause a major problem if the bulkheads are 1 1/2", like flooding?

[tbittner]

No, it won't cause a problem. It just means that the water level will probably be a little higher then optimal in order to get that much flow over the top of the overflow box.

[JoJo]

hopefully i can find blue acrylic to make a bigger overflow section

[tbittner]

Acrylic can be painted. You can keep the overflow box you have. Just notch it where it joins the glass and add in a 5" tray to extend the overflow. Hopefully you know what I mean.

Frankie has pictures of his coast to coast overflow box and that is a great idea.

[jnohs]

if you want to hold it securly in place with a hole allready there. you should get a small piece of plexy glass and clamp it over the hole on the out side of the tank. then start drilling thru the new plexy glass ikn the same spot of the old hole. this will help your bit from wriggling around crazly. when done just pull the new plexy off and you should be good.

[JoJo]

Terry i dont think i grasp what you're saying. the tank has a sheet of acrylic across the whole back, then there's a seperate sheet fold into the overflow. but what would happen if i notched the top of the overflow so that the teeth went further down?

Jnohs, thanks for reading. are you referring to drilling the tank? if so, the acrylic template sounds good. clamping it may be a little tricky but thats part of the fun.

[cracker]

Originally Posted by JoJo

Terry i dont think i grasp what you're saying. the tank has a sheet of acrylic across the whole back, then there's a seperate sheet fold into the overflow. but what would happen if i notched the top of the overflow so that the teeth went further down?

JoJo ,Can You take some pics of the overflows You have now? Hold off on notching the teeth deeper until we see what Ya got. By making the notches deeper the water won't drain off the very top surface, which is what You want.

[JoJo]

i'll get some shots after dinner

[tbittner]

Good point. Lets see some pics!!!