drilling 20 long?

[Sniperhank]

Unless using a bean overflow setup, you shouldn't restrict the flow coming from the tank. There are a handful of reasons towards this, but the bean overflow addresses this by using three different lines plumbed in...with the third being wide open and slightly higher than the others to prevent overflow.
As for the size of the hole, I would want it to be just big enough for the bulkhead so it can be secured properly and tightly.

 

[evil Nick]

Unless using a bean overflow setup, you shouldn't restrict the flow coming from the tank. There are a handful of reasons towards this, but the bean overflow addresses this by using three different lines plumbed in...with the third being wide open and slightly higher than the others to prevent overflow.
As for the size of the hole, I would want it to be just big enough for the bulkhead so it can be secured properly and tightly.

Yes, but there are different size bulk heads as well. Am I looking at a 1", 1 1/4?

the size wasnt a huge issue if I was putting a ball valve in for adjusting but if youre saying not to do that Ill need to make sure the pipe size is correct to not cause problems.

 

[coralbandit]

1" pipe flows 750GPH with gravity..
My 180g runs on 2 overflows with 1 @ 1" outflow in each overflow.
Most commercial drilled tanks have bulkheads that fit 1" pvc pipe..
My 75 , 120[ X2] and 180 all have the same size bulkheads...
You are really overthinking this..If it fit you could run a 4" drain without it ever causing an issue even if you only had a toddler pee in to tank for flow...They run on how much the pump supplies and gravity..There is no such thing as too large of an out flow ,but most have agreed that 1" is plenty...
Don't go under 1 " pipe for outflow...

 

[evil Nick]

1" pipe flows 750GPH with gravity..
My 180g runs on 2 overflows with 1 @ 1" outflow in each overflow.
Most commercial drilled tanks have bulkheads that fit 1" pvc pipe..
My 75 , 120[ X2] and 180 all have the same size bulkheads...
You are really overthinking this..If it fit you could run a 4" drain without it ever causing an issue even if you only had a toddler pee in to tank for flow...They run on how much the pump supplies and gravity..There is no such thing as too large of an out flow ,but most have agreed that 1" is plenty...
Don't go under 1 " pipe for outflow...

good point i guess, I was worried about being smaller than larger. I didnt want it to be too small and not get enough turnover or have the pump be to fast (though that can be adjusted as well i guess)

 

[evil Nick]

I picked up a couple 1" bulkheads. I figured those were large enough.

https://www.amazon.com/gp/product/B0002DKAL4/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1

I planned on one for out and 2 for return. I was thinking of going smaller for the returns and using them on the left and right for powerheads/circulation over my wavemaker. I will have to buy a couple more. I ordered my bits as well. So I was thinking of using this as the out surface skimming, and maybe getting a second as a backup but I honestly dont think it will clog up (but who knows) and then maybe two 3/4 returns I will place some diverters on (which Im having a tough time finding).

Im looking at drilling designs and there are a ton of them people do. Id rather not utilize space with an internal overflow (unless I have to and can always add it later I guess), and dont trust anything external.

Im starting to think using my 29 as a sump is just WAY overkill, even if only half utilized..... its just that I already have it, and its beat to heck anyway.

I might just save drilling for the returns and use these honestly

https://www.amazon.com/dp/B018J3RHF...a7&pd_rd_r=BWMDGESSA8R9EF0EEZCJ&pd_rd_w=xw0Ck

 

[evil Nick]

so heres my design. I just did this in photoshop. These are all the parts Ive ordered so far. I opted to use the HOB style returns to avoid too many holes in this small surface area. The over flows are 1", each return is 3/4. The one with the drain cap I will put low and then use a piece of pipe between the bulkhead 90 and the screened cap to get the height I want. the other bulkhead will use a 1" PVC 45 of which I will angle at the correct slight as a backup overflow in case the first clogs. I dont personally see it ever clogging but you never know. Behind the tank, not in each picture I plan on venting both over flows (plumbing experience) for good flow and possible noise reduction. I will cap each vent with a flow check valve in case.
My other option is actually just having the screened overflow just stick straight in from the back instead (higher up tho) of the 90, then having them staggered and using the pump to regulate water height.

From there they will go to the sump and back in through the HOB returns which I will also utilize for flow over my current powerhead, which is really powerful.

Any suggestions, questions, comments?

Thanks for the help so far and please take into consideration this is a photoshop I made in about 15 minutes with web pics and not to scale AT ALL lol.

on a side note, Ive started taking out my rocks and placing them in covered aerated buckets to kill the algae on them. Its been a week and this mutant algae is laughing at the 110% blackout. I actually think its making it stronger.