Tank Journal Archive

[Lesley]

Hi,
Long story short, the Laguna 6000 return pump we have been using was starting to fail, we were told that it was totally our fault by installing (after being told by a very exp reefer was a good idea) a one way valve on the return line and plumbing with 20mm PVC causing back pressure on the pump. (it was also close to 8yrs old )

So we hunted around and purchased a new Laguna 7600lt/hr. And changed the first bit of plumbing to 38mm, with a reducer bush on each of the return lines after they split. So we gathered there would be a massive increase in flow.
We have still been getting a little of the slime in the sump, when the pump that blew our electrics was running (it was a 6000lt/hr) the slime had stopped. So more flow, should be good right.

HaHaHaHa - maybe not !!!

The flow was so strong it actually blew one of the return pipes completely off, well it took about 20sec to get back to the plug and turn pump off, and another 2 mins of the tank back siphoning onto the bloody floor.

I have never heard my husband curse and swear so much in his life. He was sitting right next to it when it became unglued and shot off, so he was covered. I could do nothing but laugh.

I still dont know if hubby was cursing because he was all wet or the thought that his first plumbing job had actually come undone (he was so proud of it ) and being an absolute perfectionist, i personally think is ego had been hurt.

Well, re glued little more tightening on the union and all good.

So lesson is - don't trust your plumbing when upgrading pump.

 

[Ziggy]

Glad it is fixed now though :)

 

[grimnir]

I feel your pain. I run the laguna 16000 on my big tank. It has blown its return line a few times randomly. usually end up with 100 or so L of water on the floor from it.
Wet Dry Vac is my best friend :)

 

[Lesley]

I feel your pain. I run the laguna 16000 on my big tank. It has blown its return line a few times randomly. usually end up with 100 or so L of water on the floor from it.
Wet Dry Vac is my best friend :)

What the hell Laguna 16000 ??? How big is your bloody tank ? Lol :)

 

[grimnir]

What the hell Laguna 16000 ??? How big is your bloody tank ? Lol :)

big tank is 8x2x2.5 :)

 

[Lesley]

big tank is 8x2x2.5 :)

That's not much bigger than ours 7 x 2.5 x 2.5. Do you not find the flow a but to fast ? Have you ever had problem with water passing over chambers in sump too fast and not having time to consume the nasties ? Very interesting ? Can we ask please what is the width of the plumbing directiy from pump and does it split to 2 returns ? And what width is your return lines entering the tank ? How many downpipes & width please ? Thank you. ( hubby wants to know ).

 

[grimnir]

No issues with it.
Main reason of going so large was that it would produce enough flow to do anything I wanted.
have a manifold it feeds which connects to Chiller, 2x Reactors and one bleed off for excess flow.

 

[macca_75]

I have the 11,000 lph on a 8x2x2. Far to much flow IMO. I use a 1" pipe all the way through, split into 2 outlets when it enters the DT. 1 Side creates a minor ripple on the surface about 7' away. Way to much.

Oh - plumbing that has been glued should never "come apart" unless you had only just glued it and not allowed it to cure. Besides which, we deal with flow and not "pressure".

 

[MagicJ]

What glue did you use?

PVC cement effectively dissolves, and fuses, the pipes together - I am pretty sure that I couldn't get any of my joins apart even if I wanted too.

 

[Lesley]

What glue did you use?

PVC cement effectively dissolves, and fuses, the pipes together - I am pretty sure that I couldn't get any of my joins apart even if I wanted too.

Yeah it was PVC plumbers glue. Hubby says he obviously didn't put enough on at the time he plumbed.
So double on this time.
That''s his excuse anyway :)

 

[grimnir]

Sorry @Lesley missed your second part to that question

I run twin 1" returns from the pump, each has 3 90° bends
the manifold is 1" piping too with 2 90° bends leading to it.

 

[MagicJ]

I am no plumber, but I wouldn't be re-gluing the same pipes unless all of the existing cement was completely removed, which is probably impossible. The cement needs to react with the PVC which probably won't happen if there is still some residual cement in place.

@VaultBoy might be answer this one for us :)

I somewhat agree with @macca_75 above with the reference to flow rather than pressure, but the fact that the pipes separated in the first place suggests that there was some pressure coming from somewhere.

 

[Buddy]

I have always used the pvc primer before gluing the pipes together. The only way the are coming apart is with a saw!

 

[VaultBoy]

Always use primer first and then glue. If you clean an old glued joint well with a little sandpaper or a file and clean extra well with primer you can re stick it. It always feels better to replace an old joint altogether for piece of mind but sometimes it is not possible...

Properly glued joints in pressure rated (99% of aquarium plumbing pipe is rated) P.V.C pipe should hold pressure orders of magnitude above what an aquarium pump will ever produce. The only pumps I know of that would create potentially dangerous pressures are used for closed loop circulation systems which I dont believe is the case here. More likely it was a mechanical failure through expansion/contraction or vibration that caused it, or the plumbers fault...

 

[Lesley]

Always use primer first and then glue. If you clean an old glued joint well with a little sandpaper or a file and clean extra well with primer you can re stick it. It always feels better to replace an old joint altogether for piece of mind but sometimes it is not possible...

Properly glued joints in pressure rated (99% of aquarium plumbing pipe is rated) P.V.C pipe should hold pressure orders of magnitude above what an aquarium pump will ever produce. The only pumps I know of that would create potentially dangerous pressures are used for closed loop circulation systems which I dont believe is the case here. More likely it was a mechanical failure through expansion/contraction or vibration that caused it, or the plumbers fault...

I say let's blame the plumber his name can no longer be "mr perfectionist ".

 

[MagicJ]

I say let's blame the plumber his name can no longer be "mr perfectionist ".

Not everyone can be perfect at everything :p

It's being prepared to learn and try new things that counts...

 

[Tannum_Paul]

Use a heat gun and you can pull apart any glued pvc joint, people often do it to retrieve expensive fittings. Clean them up with sandpaper and they are as good as new.

There are different pvc glues remember for pressure pipe and drainage pipe......blue is drainage and green is pressure.

The fussing of the pipes is not like using weldon on acrylic, it only fusses the very very skin of the pvc.

 

[Lesley]

Use a heat gun and you can pull apart any glued pvc joint, people often do it to retrieve expensive fittings. Clean them up with sandpaper and they are as good as new.

There are different pvc glues remember for pressure pipe and drainage pipe......blue is drainage and green is pressure.

The fussing of the pipes is not like using weldon on acrylic, it only fusses the very very skin of the pvc.

Interesting the different glue colour you mention. We have clear glue ? What's that for ? Thanks.

 

[grimnir]

Clear is for non pressure pipes too.

 

[VaultBoy]

All PVC glue will be suitable for aquarium pressures. The blue glue is also pressure rated but requires 24 - 48 hour cure time. I would always recommend using clear glue and primer simply because it wont stain the floor or cabinets etc. if you spill it (and it looks better). A properly cleaned and glued joint in PVC will never fail under normal aquarium use. If there is a mechanical stress on the pipe/joint then it may fail. The plain drainage glue will be substantial.