Removable overflow for closeloop?

SynDen

Administrator
Staff member
M.A.S.C Club Member
M.A.S.C. B.O.D.
M.A.S.C President
M.A.S.C Webmaster
#1
So as part of my design for my big tank I have several holes in the tank on the bottom and the sides for closed loop plumbing. 8 holes total with 4 through the bottom of the tank. I am plumbing these with heavy duty sh80 bulkheads, with extra thick o-rings, as I dont ever want to have one of these fail, but I want to have a backup plan in place before I start to fill the tank.

So this got me thinking of possible ways I could remove one of these bulkheads without draining the entire tank. Which is what would happen if one did fail without a backup in place, especially if its one of the 4 in the sand. I dont ever want to have to drain 600+ gallons of water from the tank, not to mention the temporary re-homing of all the inhabitants.

My current thought is to take some 4" pvc pipe and silicon (or maybe solvent?) a 5" tall piece around each bulkhead in the sand bed, and a 2" tall piece around the back wall bulkheads.This gives about an 1 or 2 inches above the sand bed, but I can fill in around it with sand. In the event of an emergency I can take a 4" pvc pipe with a coupler on one end and slide it in over the pvc piece mounted to the tank, there by creating a temporary overflow which I can drain and be able to replace the bulkhead as needed.

Problem is not all of the bulkheads will be out in the open where I could install this temp overflow without moving rock, and some are on the back wall. Also white pvc on my back wall would look horrible on black acrylic and black pvc would look horrible in the sand bed even if I try and hide it.
So maybe use some 45 and different length tubes to get around them? I thought about flex pvc but the 4" size is very expensive, and so is the 4" clear pvc pipe too.

Other thought I had was to make an acrylic one of sorts, although keep the dimensions more square instead of a tube

Anyone have any ideas or experience around something like this? Would love some ideas and input
 

TheRealChrisBrown

Reef Shark
M.A.S.C Club Member
ex-officio
#2
I like your idea for the sand bed, siliconing/solvent a slip coupler to the dry acrylic while the tank is as is. Then just add the extension tube if a problem arises. I think the thought of having to move rock around to get to them later wouldn't be a huge deal because it's that or lose all the water in the tank. Move the rocks, but only if necessary.

As for the bulkheads on the sides, that's a tricky one because you'll need to be able to remove the BH nut, push the BH into the tube, and then the tricky part is getting a new BH through the hole. That's why I'm not sure a pvc tube with a cap on it (my first thought) or an acrylic box of some sort would work.... Stumped.
 

SynDen

Administrator
Staff member
M.A.S.C Club Member
M.A.S.C. B.O.D.
M.A.S.C President
M.A.S.C Webmaster
#3
I thought about the coupler idea, and it might actually be simplest method. The 4" couplers are tall though so I would likely have to cut them in half and maybe trim some more off.
For the side I was thinking the same idea mostly, except the tube would have a 90 at the bottom with a tube straight up from there. My main issue with this one is that the back is black. which means I would need to find about 10 inches of black or clear 4" pvc/acrylic, so that you cant see the rings around the bulkheads as much. Most stores sell that stuff in 5 or 10ft lengths and I hate to waste the rest of that pipe especially since they arent all that cheap. Although a trip to Platicare is in my near future maybe ill find something that will work there.
 

TheRealChrisBrown

Reef Shark
M.A.S.C Club Member
ex-officio
#4
What if you just glue a 1 inch piece of pvc, and then if you ever need to replace the bulkhead you just use a slip x slip coupler and press it onto your glued (siliconed) piece. If 1 inch of pvc would provide a good enough seal for enough time to complete the repair?
 

SynDen

Administrator
Staff member
M.A.S.C Club Member
M.A.S.C. B.O.D.
M.A.S.C President
M.A.S.C Webmaster
#5
Ya I was thinking 2" likely would be a better seal, but might need to experiment a bit and find out the shortest height I can go, and still maintain somewhat of a seal. Doesnt need to be a perfect seal, just needs to hold back the water for 15 min or so while you switch them out
 

halmus

Registered Users
M.A.S.C Club Member
ex-officio
#6
I think the PVC pipe idea is a good start. What if you cut some acrylic rings that had a snug fit around the OD of the PVC and then slid those down to bond with the acrylic tank bottom and the outside of the pipe?

Then, the PVC wouldn't only be bonded by the face of the pipe to the tank. A certain amount of the side of the PVC would also be bonded (depending on the thickness of the ring) providing a little more strength and could easily be hidden by sand. The few times I have bonded PVC to acrylic, it stayed but didn't seem to have the same structural integrity of acrylic to acrylic.


Sent from my iPhone using Tapatalk
 

SynDen

Administrator
Staff member
M.A.S.C Club Member
M.A.S.C. B.O.D.
M.A.S.C President
M.A.S.C Webmaster
#7
I think I follow you. You kind of answered one of my questions about the strength of the bond between pvc and acrylic too. So makes sense to try and make these a bit stronger by using the rings instead of just pvc
 

halmus

Registered Users
M.A.S.C Club Member
ex-officio
#8
Ya, it's a little hard to explain in words. A drawing of what I'm thinking would go a long way. I'll try to draw something tonight. I'm just thinking of what I guess you would call a flange. If you got a tight doughnut shape that fit snugly around the pipe that was made from 1/2" thick acrylic (maybe 1/4" would be enough?) you would have a lot of surface area to bond to. The only problem is machining the acrylic to a relatively tight tolerance.

As far as the bond between acrylic and PVC, I'm just speaking from my experience. Others might have had better luck.


Sent from my iPhone using Tapatalk
 

SynDen

Administrator
Staff member
M.A.S.C Club Member
M.A.S.C. B.O.D.
M.A.S.C President
M.A.S.C Webmaster
#10
I like it, that makes sense now. Gives it strength, a better seal potential, and a lower profile. Also likely protects the bulkhead somewhat from the daily abuses of the a reef tank.
I think Ill have to see if I can get the pieces cut at Plasticare or maybe have ADHI make some for me. Thanks
 
Top