cracked another tank today

At least it wasn't drilling this time, think i have that down now.

i am using 2 ten gallon tanks connected by 2, 1 inch bulkheads one in each corner, for a sump/fuge for my 55 gallon. i ran the bulkheads between both tanks. this is kind of hard to describe, but i placed both tanks next to each other and ran a single bulkhead though the holes in the tanks using plastic nuts to secure bulkhead to the tanks (attached a picture).

had everything set up and running and was doing "power failure" tests when i noticed the bottom of the stand has a little bit of water on it. found a crack shooting from on of the drilled holes

i am assuming that the way i had the bulkheads installed applied a "twisting" force on the side wall of the tank, cracking the tank. or i over tightened that bulkhead. didn't use a wrench or anything crazy like that.

I think i am going to go back to the original plan of using 4 total bulkheads and just cementing a piece of PVC pipe to connect them.

any thoughts

 

yeah, if I was going to do it that way, ide use PVC pipe inbetween each bulkhead. And then your going to have to make sure that each bulkhead is perfectly centered with each other.

 

dang! i agree with rodcpierce, id plenum the two together. Id also not put the pvc in until they were in their permanent place as to not risk a potential stress crack in moving the tanks.

 

yeah i will have to do it in the stand. only problem is that if i have to remove them it will be a huge pain.

 

i got the last set of holes pretty centered, drilled one, set the other inside and traced the tank through the drilled one. i guess i should use the longest possible length which wont be much so it will allow the maximum flexibility

 

I would say add a little more space between them and add a flexible hose between them just long enough to flex up or down, its hard to get the measurements down to the 1/32 of an inch or smaller, because as soon as you add the weight to the tank the weakest point will give, in this case the side but if you use a small piece of flexible hose that part will give.

 

i thought about flexible hose but was worried about not keeping the flow between the tanks easy.

how would i go about going from a 1 in bulk head to flex hose back to 1 in bulkhead??? obviously it would have to be a large diameter hose to hold shape. im just worried that 3 or so inches isnt enough space to make the transitions. ill definitely have to look into this some more though.

thanks

 

here, how about this. Cut a piece of 1/2 inch plywood to the EXACT size of the edge of your tank, IE:the end you drilling. Then, drill 2 holes through the wood in the place you want the bulkheads. Have one person hold the wood in place on the end, drill your 2 holes. Then have them hold it in place on the other tank, and drill your 2 holes on that one. This should ensure that they are placed in the correct spots on each tank, and should minimize any side stress from being out of center with each other...

 

i actually think i got the holes centered really well, i used cardbboard template that i made 2 "copies" of to go over the circles i drew threw the already drilled tank. the glass "plugs" that came out looked like they were perfectly outlined in black from where i traced.the holes

 

I'd use only one large pipe.

Since it is a 55 gal stand you probably don't have room but if you do then bring the pipe out in the front of each 10 gal tank and make a U. It is much more forgiving since the U will absorb some stress. That's what I did but I have a bowfront.