Adding an overflow while tank is empty.

[M&M]

Hello, First let me say thanks for all the information I've gathered from this great site!

I'm picking up a 75gal Acrylic FOWLR in a few days. (My last SW tank was in 1990) The tank is well established w/ shallow SB, LR, sump etc. The tank currently doesn't have a skimmer. I plan on adding an Aqua C 12O and CL while the tank is down, with the intention of transitioning to a reef as I learn more. Currently the tank only has a single corner over flow and based on my reasearch this will not provide the drainage flow I will need for the CL.

Has anyone installed an internal corner overflow while the tank is empty? I plan on having the overflow made up (1/4 Acrylic) and ready to install before I drain the tank. Can I just glue it in (quickly and carefully) with weld-on? Does anyone have any advice or experience doing this? I'd like to have the tank empty for as little time as possible.

 

[mojoreef]

Hiya M&M. On the overflow you sure can just glue it in with weldon, thier are several threads going that show how the glue is done easily. As per using a Overflow to feed a closed loop that is not a good plan as it will create a ton of bubbles in the tank, and truely the overflow makes it not a closed system.


Mike

 

[M&M]

Thanks much Mojoreef. I spent several hours reading up this weekend and realized that your right I didn't "truly have a closed loop". My current thinking is that I might forgo the additional overflow and plumb the closed loop like the attached pic. I don't have any randomized flow yet but I think I could easily add a MBV at a later date. (The tanks is a FOWLR currently)

I haven't purchased the CL return pump yet, do have any suggestions?

(All of the CL plimbing is 1 1/2" Sched 20)

 

[mojoreef]

Yea I got a couple things you might want to concider but first tell meif you are planing for a substraight??


Mike

 

[M&M]

Yes the tank currently has about an 1" maybe a little less of fine Argonite. I like to looks of the sand bed and was planning on adding another 1" or so.

 

[mojoreef]

Cool ok if it were me, I would loose the spray bar (thier flow pigs) and use the water coming from the return to go across the surface of the water and keep that interface well oxygenated. Your cl plan looks ok but I would flaten out the returns (as in all at one level) about mid tank, that way you can directly flow either to the top or bottom as required and lessen the distance to do it. Also make the bulkheads going into the tank 3/4 as in that is what the locline is going to be and if you get thread by thread BH's they will just screw in. Also on the inputs for the closed loop I would put them somewhere high where you know you can reach them for cleaning and servicing, also a place where you know your rock scaping is going to hide them from site.
I agree on loosing the secnd overflow, I dont think you need it.


Mike

 

[M&M]

Thanks for the help Mojoreef.

I've got the day off work and what better way to spend it than plumbing the CL and setting up the tank.