refugium thaughts and questions

[stewball]

So, I want to make a refugium and fresh water ATO.
I have a 40 gal. aga and i got a 55 gal. 4 free
I want to set it up next to my 40, pump up to it and gravity feed back thru a 1/2" bulkhead( the 55 should be about 4" higher.)
I am looking to partition off 7 gal. for fresh water so i can make 5 gal of water and have some left in the tank.
Now the ??s. what kind of turnover rate am I looking for, any other problems that i dont see. i have read a lot about them and never seen what im looking to do
how much light do you think I need to stop ph drop( running the light at night of course)
I dont see others with a refug larger than the display. I want as much water volume as possible and clear out my dt.
I read refug should be 1/10th of tank because " there wont be enuf nutrients to support it long term" to me its doing its job am i missing something?
Well thats enuf for now ........ any and all replys are welcome. i have a feeling answers are going to be diverse, at least I hope so I can see different views.
TIA.

 

[JohnK]

Interesting concept. I don't see any reason that you can't have a large volume refugim, you might not keep the whole thing full of thriving macro algae, but it certainly can be done. Hint; Try googling "tyree cryptic zone" and see what comes up

The big limitation I see in the above idea would be the 1/2" bulkhead as a drain. That will only handle a very slow flow, and with only a very short drop that very slow flow would be even slower. Maybe a couple hundred GPH at best if your lucky.

How much PH drop are you currently seeing at night? It's probably nothing to be concerned about.

 

[stewball]

Hmm, thats something different than I have read about. All the reading I been doing and I never came across that. thanks.

 

[JohnK]

Also try "tyree zonal reef" or "tyree zonal system".

 

[stewball]

Well your right John, I did some tests ( drilled holes in a 5 gal. bucket ) 1/2 in. is way too slow. Im going with 1 in. thanks