Confused about bulkheads and combining multiple tanks together.

[lazyreefer]

Hello,

Recently I bought several 15 gallon acrylic tanks. I assume they were used in a fish store at one time, and I'm wanting to combine them into a closed loop sort of system running out of a single sump.


I have several questions and things I'm needing help on, but one involves the bulkheads. These tanks measure approximately 24" long by 14" wide and 11" tall. On the back side two holes have been drilled with bulkheads already mounted onto the tanks. One hole measures 1-1/8" while the other is larger at 1-5/8 in diameter. I assume that means a 1" and 1-1/2" bulk head is required. Is this correct ?? I've got to buy some plumbing stuff and the bulkheads don't have any numbers stamped on them.

Secondly, both holes are drilled at the same height, which is about 1.5 to 1.75 to the center off the top. I'm assuming that one hole is my return while the other is my drain, but how the heck is the drain being accomplished if you tie several tanks together ?? A multiple tank system in a fish store is not gravity fed is it ? (I know some are one big tank with dividers)

Let's say I had 1-1/2" PVC running in a loop off of a single sump. I'm then gonna tie 6 of these individual tanks into this "loop". I'm assuming the drain is occurring via the "return" pump suction rather than gravity ??(assuming the pump is of sufficient size)

If my assumption is correct, can I tie the return line of every tank into the same loop, or will I need two "loops" with a loop for suction and another for the return - both of which come off the same pump. (or is this wrong) In other words, I want to have the six tanks tied into the system in parallel rather than series. I want to be able to shut down a tank while keeping the others running.

Any help understanding whats all involved would be appreciated. I'm struggling to wrap my head around how to set it up..... :tongue:

 

[Kbra]

you can use one return line to the first tank and use the other hole to link each of the tanks together and then the very last hole of the last tank is ur drain to the sump...

 

[lazyreefer]

Thanks Kbra, but that's putting them in "series". I want them to be in "parallel" so I can pull one tank off line so to speak all the while keeping the others running.

I know that would require separate returns and drains for each tank, I'm just trying to figure out how each tank can be tied into a "loop" using just a single return pump. And if a second "loop" tied into the suction of the pump for the drains is even feasible or necessary. After sleeping on it I'm leaning towards a gravity feed into a sump below the tanks might be the best way to accomplish that.

Not sure though, if anyone else wants to chime in. What about the bulkhead size ??

Thanks

 

[jaytizzle]

For that many tanks you would need a pretty large pump but you could set up a manifold return system from a common sump (say 75 gallons) and have everything plumbed separately into the common sump. That would give you a true parallel isolatable system.

 

[Troylee]

Hello,

Recently I bought several 15 gallon acrylic tanks. I assume they were used in a fish store at one time, and I'm wanting to combine them into a closed loop sort of system running out of a single sump.


I have several questions and things I'm needing help on, but one involves the bulkheads. These tanks measure approximately 24" long by 14" wide and 11" tall. On the back side two holes have been drilled with bulkheads already mounted onto the tanks. One hole measures 1-1/8" while the other is larger at 1-5/8 in diameter. I assume that means a 1" and 1-1/2" bulk head is required. Is this correct ?? I've got to buy some plumbing stuff and the bulkheads don't have any numbers stamped on them.

Secondly, both holes are drilled at the same height, which is about 1.5 to 1.75 to the center off the top. I'm assuming that one hole is my return while the other is my drain, but how the heck is the drain being accomplished if you tie several tanks together ?? A multiple tank system in a fish store is not gravity fed is it ? (I know some are one big tank with dividers)

Let's say I had 1-1/2" PVC running in a loop off of a single sump. I'm then gonna tie 6 of these individual tanks into this "loop". I'm assuming the drain is occurring via the "return" pump suction rather than gravity ??(assuming the pump is of sufficient size)

If my assumption is correct, can I tie the return line of every tank into the same loop, or will I need two "loops" with a loop for suction and another for the return - both of which come off the same pump. (or is this wrong) In other words, I want to have the six tanks tied into the system in parallel rather than series. I want to be able to shut down a tank while keeping the others running.

Any help understanding whats all involved would be appreciated. I'm struggling to wrap my head around how to set it up..... :tongue:

bulk head sizes seam irregular on those a 1" bulkhead for the most part needs a 1-3/4" hole and a 1.5" bulk head needs a 2-3/8" hole.. bulk heads do vary from manufacturer to manufacturer so purchase them accordingly..it's always better to have the bulkhead and then drill but you couldnt do it in your case..sounds like a 1/2" return and a 3/4" drain bulkhead..fwiw..
most stores i have seen are gravity feed where all the tank drain into a large pipe like 4' diameter that runs under them like a manifold where they all tie into the same sump and a big return pump with a manifold on top that returns to each tank...it would be simple enough if you put vavles on each drain and return, you could pull any given tank off line at one time....hth..

 

[lazyreefer]

Thanks guys, anybody got any links to a "manifold" setup to help me visualize what your pointing out.

The pump size, would it need to be large because of the individual return lines, say if each one has a 5 foot head and there are 6 tanks, does that equal 30' head or is it still just 5 foot head assuming the tanks are all the same level ?

With six 15 gallon tanks, that's 90 gallons total, would I have to buy a pump based on 90 gallons or do I have to figure in the possibility of a 30' head or something else ??

If the pump is outside the sump, and I plumbed it with PVC, does the pump's ability to push water relate to its ability to suck it in too ?? For example, if I used 2" PVC on the "push" side there's no resistance, but if I used 1" on the "suck" side is the pumps now limited by the 1" pipe's resistance ?? I assume so, kind of like the ol' adage about a chain only being as strong as its weakest link.

Now I don't know why one side would be 2" and the other 1", but it helps me to understand what all affects the output of a pump and what may make it unbalanced. For example, using two pumps on the same closed system seems like it would be a nightmare trying to match the flow of each pump. (if not impossible)

Thanks again, I appreciate the replies.

 

[lazyreefer]

bulk head sizes seam irregular on those a 1" bulkhead for the most part needs a 1-3/4" hole and a 1.5" bulk head needs a 2-3/8" hole.. bulk heads do vary from manufacturer to manufacturer so purchase them accordingly..it's always better to have the bulkhead and then drill but you couldnt do it in your case..sounds like a 1/2" return and a 3/4" drain bulkhead..fwiw..
most stores i have seen are gravity feed where all the tank drain into a large pipe like 4' diameter that runs under them like a manifold where they all tie into the same sump and a big return pump with a manifold on top that returns to each tank...it would be simple enough if you put vavles on each drain and return, you could pull any given tank off line at one time....hth..

When you say 1" bulkhead requires a 1-3/4" hole...(for the most part)

What part of the bulkhead is being measure as 1"....the inside "tube", the outside threads, ?????

And what about not using the threads on the outside of the bulkhead for anything. (the threads for the bulkhead nut) I'm really struggling why bulkheads would even exist if you can't use the outer threads to tie PVC, flex hose, or whatever onto it.

I mean Loc-Line returns, or maybe a siphon screen, screw into a bulkhead inside the tank, why wouldn't you be able to screw a fitting on the outside threads to accomodate plumbing ??? :neutral:

 

[Troylee]

When you say 1" bulkhead requires a 1-3/4" hole...(for the most part)

What part of the bulkhead is being measure as 1"....the inside "tube", the outside threads, ?????

And what about not using the threads on the outside of the bulkhead for anything. (the threads for the bulkhead nut) I'm really struggling why bulkheads would even exist if you can't use the outer threads to tie PVC, flex hose, or whatever onto it.

I mean Loc-Line returns, or maybe a siphon screen, screw into a bulkhead inside the tank, why wouldn't you be able to screw a fitting on the outside threads to accomodate plumbing ??? :neutral:

this is correct a 1" bulkhead is the measurement from the inside of the outlet hole..or "I.D." i should say....the outside threads are always larger and need a bigger hole than the desired bulkhead....
here is a chart for refernce..
Bulkhead Tank Adapters online ordering

why cant you use the threads?? because they are not tapered which means when you screw a pvc threaded fitting on it they never snug up tight.... you can use teflon tape but it's bound to leak since there not designed to do that...
the threads inside are no problem because it dont matter if your locline leaks it's inside the tank.... i personally use tank jets....i hate locline myself...
1" Tank Jets - D&T Aquarium Supplies-Aquarium Supplies For Saltwater And Freshwater Aquariums, And Ponds

 

[Troylee]

Thanks guys, anybody got any links to a "manifold" setup to help me visualize what your pointing out.

The pump size, would it need to be large because of the individual return lines, say if each one has a 5 foot head and there are 6 tanks, does that equal 30' head or is it still just 5 foot head assuming the tanks are all the same level ?

With six 15 gallon tanks, that's 90 gallons total, would I have to buy a pump based on 90 gallons or do I have to figure in the possibility of a 30' head or something else ??

If the pump is outside the sump, and I plumbed it with PVC, does the pump's ability to push water relate to its ability to suck it in too ?? For example, if I used 2" PVC on the "push" side there's no resistance, but if I used 1" on the "suck" side is the pumps now limited by the 1" pipe's resistance ?? I assume so, kind of like the ol' adage about a chain only being as strong as its weakest link.

Now I don't know why one side would be 2" and the other 1", but it helps me to understand what all affects the output of a pump and what may make it unbalanced. For example, using two pumps on the same closed system seems like it would be a nightmare trying to match the flow of each pump. (if not impossible)

Thanks again, I appreciate the replies.

dont have any pics of a manifold but just visulaize 5 tanks end to end and you lay a sigle straight piece of pvc pipe over the top from end to end... now rite above each tank you put a "tee" on it so it has a drain into each tank...your pipe would look like this...---T-----T----T----T-----T---<cap the end"... well sorta lol.... the pipe would be contiunious on the top the pvc tees dont stick up like that lol...sorry i cant draw on the pc...for a return pump i would use a hefty one like like a mag24 or laguna 2400 something similiar because you will lose flow as it reaches the end of the tube...

 

[lazyreefer]

this is correct a 1" bulkhead is the measurement from the inside of the outlet hole..or "I.D." i should say....the outside threads are always larger and need a bigger hole than the desired bulkhead....
here is a chart for refernce..
Bulkhead Tank Adapters online ordering

why cant you use the threads?? because they are not tapered which means when you screw a pvc threaded fitting on it they never snug up tight.... you can use teflon tape but it's bound to leak since there not designed to do that...
the threads inside are no problem because it dont matter if your locline leaks it's inside the tank.... i personally use tank jets....i hate locline myself...
1" Tank Jets - D&T Aquarium Supplies-Aquarium Supplies For Saltwater And Freshwater Aquariums, And Ponds

Thanks again Troy, so why are bulkheads used, or maybe I should be asking how they are used ? Is it a compression fitting that holds the plumbing to the outside part of a bulkhead ? Is it glued in ?? Do they make a bulkhead with a "barbed" end so I could use flex tubing ??

These tanks I got came with bulkheads already in them, the smaller hole has a loc-line return screwed into the inside while the larger bulkhead has nothing at all. On both sizes the half inside the tank is threaded inside the bulkhead while the other half on the outside of the tank has a "slip" fitting I guess you call it with threads around the outside part for the bulkhead nut. What "slips" in the bulkhead from the outside and how is it held in place ??

Thanks again, sorry to be a pain. I googled bulkheads but there's not much info....or at least I got tired of looking at all the manufacturers selling them.

 

[LegoZ81]

for the drain lines i'd recommend sticking with hardpipe and unions to remove it if needed you want the lines to be as free flowing as possible.I personally avoid soft tubing at all costs but that is a personal thing. It does have good uses though if you use flex tubing on the intake and output lines for a short length it will isolate pump vibrations.

 

[lazyreefer]

But how do you incorporate hard pipe if you can't screw anything on to the outside threads of the bulkhead ???

 

[ddwbeagles]

Couple of bulkhead specific comments. You can get them slipxslip, TxS, SxT & TxT. Troylee is correct in that most one inch ID diameter bulkheads have an OD that requires a 1.75" hole. An option worth considering may be the new DuPont pressure "slip fitting" bulkhead alternative. Check them out over @ Bulk Reef Supply.....also one of the cheapest places to get them.

....and no, I'm not affliated with them in anyway. Just passing it on to possible

 

[LegoZ81]

If it is a slip connection on the outside, then you glue the pipe into the inside of the bulkhead.
If it is threaded you buy a threaded to slip adatper that again goes inside the bulkhead, you need to use ptfe tape to seal the threads.

You never use the outside threads of the bulkhead for attaching plumbing, also they are an odd size that you probably could not find fittings for anyway, but you never know...
Also the gasket always goes to the wet side. I'll see if I can find/link the bulkhead tip thread.

That was not very hard lol:
https://www.reef2reef.com/forums/f30/installing-bulkhead-tips-34973.html

Also with the Uni-Seal like adapters I would be concerned with the amount of pressure that would need to be used to get the pipe slipped into place. I have found it is pretty difficult to get the pipe in to place. You could use a silicone grease (specific for plumbing use) to make it easier, but I have not tried this myself.