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When I plumbed my 90G, it took me 6 months. Plumbing the 300 took me about 6 hours. I enjoy the creative aspect of plumbing.
A couple of tricks that I’ve learned over the year.
• Always use primer on hard PVC. Never use primer on flex PVC.
• Always dry fit everything first.
• Wipe off excess PVC cement. Both inside and out. Disassemble couplers when gluing so as to allow access to wipe of excess cement.
• Plumbing at the pump intake should be short and direct. If this is not possible, a larger diameter pipe should be used and the diameter should be reduced right before the pump. Minimize resistance on the intake.
• Elbows before the intake of a pump can be a source of microbubbles.
• Align the couplers uniformly throughout all runs. This allows any section to be replaced with a single coupler (one piece on each end of the section).
• Use two 45s rather than a 90 wherever possible.
• Use flex PVC wherever possible. Always attach pumps to a section of flex PVC.
• Don’t allow plumbing to stress the tank glass by acting as a lever.
• Use a silicone lubricant on all O rings.
• PVC is easy to ‘cut to size’ with a dremel. If a piece is just a little too big, cut it down. Make your own fittings.
• Make sure you have a way to isolate any pumps for maintenance or in case of a failure.
These aren’t really guidelines so much as rules. Short cuts here are just not worth it.
Return Pump Selection
For my return I selected the Eheim 1262. For redundancy, I will use two of them. This was not an easy decision and I researched many other great pumps, but in the end, the only other pump that came close was a Red Dragon. At 4 to 5 times the cost per pump and no spare parts, the Red Dragon pumps are really hard to justify.
The biggest limitation of the Eheim pump is that it does not have high flow like many of the other return pumps on the market. However, I’m not sure that high flow through the sump is really necessary. I only want enough turn-over through the sump to keep my skimmer happy. This is just short of 700gph or slightly more than twice the display capacity.
The Eheim specs that were important to me in making this selection are:
• External
• Low heat transfer
• Quiet operation
• Max output: 900gph (estimate at 600 after 8 feet of head loss)
- Two pumps should give apq 1200gph
• Power consumption: 80W per pump.
- Two pumps would be 160W
Another very important thing is the ability to get spare parts or a replacement pump if necessary. Just about everyone stocks these pumps and parts are often available.
Finally, Eheim has a great reputation and the average user ratings are almost always good. I have used them for other purposes and agree with the general consensus.
Modding the Eheim for PVC plumbing
Eheim pumps come standard with barbed fittings for flex tube. This is pretty standard stuff with fresh water tanks, but didn’t really work with my plans for plumbing. I really needed a way to connect a PVC fitting.
The pumps are fitted with ¾” FPT (Female Pipe Thread), but I’m not sure how standard the threading is. Typically this thread would be tapered causing the male and female threads to jam together forming a solid connection. However, the Eheim thread does not appear to be tapered. The obvious concern is an inadequate seal resulting in leaks. Teflon tape might address this, but I suspect a lot would be needed and it would need to be reapplied whenever the pump was disconnected for cleaning. The original part is shown here.
Note the ‘O’ ring just before the hex head. This is how Eheim maintains a water tight seal. I figured 'why reinevent the wheel'. If the 'O' ring works - keep it.
Using a dremel, I cut the barb adapter off.
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The top view shows a relatively straight inner core. I rounded it out a little in hopes of minimizing turbulence. The concern here is micro bubbles.
For the intake I used a 1” to ¾” PVC reducer. This worked really well because of the hex shape matching the Eheim hex to within millimeters. For the outtake, I used a ¾” to ½” PVC reducer. This also worked well although the hex heads were slightly different in configuration. Only the intake is shown here. The first image shows the IPEX markings on the PVC fitting. In the second image they have been ground off.
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I used Mr. Sticky’s underwater glue to bind the two pieces together.
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The above process was repeated for the intake and outtake of both pumps.
Plumbing the return pumps
With the modded Eheim fittings installed back on the pump, I continued to plumb the return plumbing.
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The first step was to attach the union fittings. For the intake it is a 1” union and for the outtake it is a ¾” union. The ball valve completes the pump plumbing.
On the tank side, I used a section of spaflex (Flexible PVC). I used spaflex so the I didn’t need to be concerned with an exact alignment with the pump and to minimize any transfer of vibrations from the pump to the sump.
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The Styrofoam riser brings the pumps to the correct height and should also help to further minimize vibrations.
The astute reader would note that there are no valves for isolating the pump from the sump. The primary consideration here was space and a valve just wouldn’t fit. However, I do have a solution. The bulkheads are threaded on the inside. I can attach a threaded cap on the inside (wet side) to temporarily hold back the water. With a small Tupperware tub, I can catch any water that leaks while disconnecting the pump. Once the pump is off, I can attach a capped union such as is already installed on the center bulkhead. The net result is I do have a strategy for removing the pumps.
The first picture below shows the 5 tank fitted bulkheads and also shows the loc-line fittings. The bulk heads were installed with nothing more than a hand tight seal (no silicone or glue). The other 3 pictures show the vertical section from the return bulkhead into the stand.
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I used hard PVC to plumb from the return bulkhead into the stand for a couple of reasons. This section of plumbing is visible and I wanted it to be straight. I had originally thought to use spaflex as far as the vertical section, but the flexible PVC doesn’t have a small enough bend radius to go from the roof of the stand to the vertical run without looking unfinished.
Note the check valves installed just below the top elbow. These serve an important role in the overall tank operational strategy. If one of the two return pumps fails, the check valve will prevent the failed return loop from back siphoning (or at least limit the rate of back siphon). It also allows the return pumps to be stopped without the water level dropping in the main display. I may want to stop these pumps for feeding or other maintenance such as sand siphoning. What these check valves do not do is protect against a flood. The sump has full capacity to hold all of the water that could potentially back siphon in a full power failure. In my opinion, check valves should never be trusted to be water tight.
If the check valve on the return line needs to be serviced (for cleaning, or in the event of a failure), the water level in the display can be dropped below the return lines. This is really only a couple of inches and should be a reasonable strategy for emergency repairs.
One final observation on this section is in regards to the ¾” bulkheads. I found these to be extremely poorly made. Specifically, the PVC pipe does not fit securely into the slip side of the bulkhead. This has me a little bit nervous, but I did use extra PVC cement in an attempt to get the best weld possible. The zip ties attaching the plumbing to the stand are intended to minimize any stress on the bulkhead weld due to twisting or turning of the plumbing. If need be, I will replace these bulkheads. Maintenance would involve lowering the water level and cutting them out with a dremel. This really would be ‘no big deal’, but I first have to find a better bulkhead.
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The spaflex is zip tied to the frame to hold it in place. This is a temporary measure. I figure it’s sufficient for the purpose of this thread, but I wouldn’t leave it like this for anything more than testing.
Plumbing the overflow
As noted in the planning section, I am using a modified beananimal overflow. In contract to the ¾” bulkheads
(no name) used for the return plumbing, the 1.5” bulkheads I am using for the overflow are really very well made
(Lifeguard Aquatics). This first picture shows the unions glued to the bulkhead.
One problem that I knew I was going to have to deal with was the overflow not aligning properly with the stand. This came about for a variety of reasons, but it was easily solved. I had considered using 1.5” spaflex here, but I really prefer working with hard PVC and the benefits of spaflex don’t really apply to overflow plumbing.
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Using two 45 degree elbows together creates a step. However, the step was way more than I needed, so I cut one side of the connecter in half. The result was a smaller step that was still too big, although manageable. You can see in the picture with the section attached that it enters the tank stand on a slight angle. I can live with this.
Another challenge that needed to be overcome is the orientation of the sump in relation to the overflow. The sump runs the full length of the tank from left to right and is designed for water to flow the full length before being returned to the main tank. The overflow is dead center.
The principals of the beananimal overflow make the problem somewhat easy to overcome. It is really only necessary for the ‘full siphon’ standpipe to enter the first chamber of the sump as this standpipe carries 90 percent of the total flow. The ‘open channel’ standpipe carries the remaining flow while the ‘emergency’ standpipe is dry under normal operation. Having the ‘open channel’ standpipe bypassing the skimmer section should really be inconsequential.
To relocate the ‘full siphon’ standpipe into the first chamber I used two sweep elbows.
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The gate valve allows for fine tuning the siphon with an amazing degree of accuracy and ease. This task is much more difficult with a ball valve as you really need the accuracy. The weight of the plumbing is supported by the stand to ensure there is no additional stress on the bulkheads or glass.
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The standpipes are different heights depending on their function. They are friction fit and can be easily removed. There are a couple of outstanding tasks such as fitting a strainer to the top of each standpipe and drilling holes in the top of the open channel standpipe. I’ll update the thread with a picture once I’ve done this. For now, the height of the standpipes is a best guess. I will only really be able to finalize the configuration once water goes into tank.
