Ideal flow rate for a 200 gallon N.v.v tank?

[sharrakor]

I'm in the process of designing a huge tank to house my growing newts, and am still heavily in the planning stage doing as much research as possible, but one thing I could not figure out was what the best turnover rate for the tank would be. I have extensively used the search function on the site (and google; a cool tip is if you type "site:caudata.org string" it will only return results from caudata.org) but wasn't able to find a good sort of rule of thumb to go by; all cases were specific limited examples, and in much smaller tanks.

I plan on making a big post with all the details before I actually buy anything, just to double check that everything is ok, but this is an essential part of the design that I need to work a lot of other things around.

The details (so far; subject to change if need be):

200 gallon tank with 50 gallon sump. Undecided on if this will be a wet/dry filter, but it likely will be.
Self designed "overflow" that pulls water from the middle of the tank into the sump, so as not to disturb the newts hanging out on the surface of the water or the bottom of the tank.
Will house around 40 Notophthalmus viridescens piaropicola. 3 bought from a pet store, 37 captive bred over 2 mating seasons. This species is only found in peninsular Florida, and is fully aquatic (though I always leave some land, just in case).
It will be a heavily planted tank with high light. I am currently testing to see exactly what kind of light the newts are comfortable with. So far it looks like they don't really care.
Will have some form of CO2 injection. I've searched around on the site and seen that many people do fine with CO2 injection. I will have a large number of safety measures in place to be sure the CO2 levels stay fairly low -- I was thinking 10-15 ppm max. I will also have a computer system hooked up to the tank to alert me if anything is out of order.

As I said, because my overflow is going to be a custom design unlike any I have been able to find so far, largely due to the fact that I want it to pull water from the middle of the tank rather than the top, I will need to thoroughly test it.

To make matters more complicated, it cannot be a standard style of overflow, because a standard overflow with air exposure will cause CO2 losses, which means more CO2 needs to be added, which increases volatility.

As such, I need some idea of what flow rate I should have in the tank. So far, I was thinking a 4-5x turnover rate might be good (I'm talking about just the main tank, so 200 gallons x 4 or 5 = 800-1000 gph). But I'd love to hear what you guys think! When it comes to plumping and drilling holes in the side of the tank... I really want to get it right the first time around

 

[Adogowo]

Sounds like you have a great idea and I applaud yor efforts at researching the information you need. It sounds to me like the flow rate is good so long as your not adding a lot of current. Do you have a diffuser planned for the inlet? If you do then I would say great. As far as drilling the tank I have never done it but it seems straight forward. I have noticed that reef ready aquariums often are equipped with a baffle around the drilled holes and wonder if this is a way to reinforce the hole in addition to keeping fish out of the intake. Hopefully you get some more feed back soon so your not going at it alone. Good luck.