River Manifold Build Question


I’m in the process of replacing all of my nano tanks with “standard” size aquariums (1x 40 breeder and 2x 55 gallon aquariums) and decided that, since I’m going through the hassle of rehoming all my fish, I should set up a proper river tank this time.

To do this, I am using the well-known build from this article. I’m finding myself stuck on how to finish it and was hoping those of you who’ve built one previously could help me figure out a couple things.

I have built the manifold and two intakes (6.5” long each) from 1” diameter PVC in an Aqueon 40-gallon Breeder tank and am currently just ironing out the final details.

The one I’m currently stuck on is how tall to make the stems that hold the power heads. I’m not sure how long to make them.

I would figure the pvc pipe the sit on would need to be at least 2” long to at least clear the rocks and sand, but wonder how much taller it would need to be in order to optimize the flow.

I’ve also noticed that in most builds people do, the powerheads are at two different heights. I was wondering if this is an important part of the design or if there is any advantage or disadvantage to putting them at the same height instead.

I will be deviating from most of these builds in the fact that I’m planning to use a pair of Aquaclear 20s instead of the Aquaclear 70s (or equivalent) that most people use. I’m building the tank for a mix of fish and not all want the crazy currents hillstream loaches prefer as well as the fact I happen to have the former on-hand and do not own the latter. I do plan to give myself space so I can replace them with the latter (or something between) should I decide to do so later.

I also intend to do another DIY mod that would place the intake of two HOB filter intakes (Aquaclear 70, again what I have on-hand) near the manifold intakes and the output/return near the powerheads, so this will add to the current.

So to get back to the question, how tall should they be?

Should they be different heights?

Sorry for the lengthy post, just wanted to be certain you had all the information needed to answer my question!


As far as the height, it needs to corelate to your hardscape. I use a technique in my upper tanks in my rack where substrate is sloped from 5-6" deep in the rear to 3" in the front. This allows the tanks to be viewed better from more angles. In that situation I would say you should build your rear intake and pump risers a few inches taller than the front.

The second reason some people may mount one higher is to put an area of low velocity at the substrate on one side so the fish can rest. The higher the pump from the substrate the slower the velocity at substrate level, and the faster the velocity higher in the tank.


My main tank aquascape is consistent with that of a creek or river bed, boulders, stones & gravel. Although, I don't use power heads to create added flow, the two oversized HOB's provide more than enough flow for my Riverine species. In particular Filamentosa & Denison Barbs.
If I were to add powerheads, they would be attached to the glass on opposing ends, one low, the other high, using suction cup mounts, not PVC tubes.
Good luck with your design. Be sure to post pics.



That’s the only picture I have so far. Currently, dry run has it fitting perfectly in the tank.

This weekend I want to clean the outside of the tank and apply self-adhesive vinyl to the back and sides.

As for the manifold, I want to cement the end pieces and stands, but plan to hold off a little more on the long pieces so I can adjust to accommodate for the power heads and sponges on the intakes before cementing those. I will then spray with Krylon Fusion so it blends with the tank and give it about a week to cure before placing it in the tank, adding substrate, etc.

I also plan to build PVC hang-ons for the HOB filter intakes. Thinking basically a variation on a toilet paper roll hanger with a sponge filter where the toilet paper would normally go held in place by a heater suction cup clip, but I may get a little fancier than that to improve flow by using 45 angle joints to make a lighting bolt shape and stake it in the substrate at an angle on the capped end. Either way, will connect it to the HOB with vinyl tubing to limit any reduction of intake.

As for having a place for the fish to rest outside the flow, there will be a gap at one end of the tank before the power heads that will have greatly reduced current and I’m planning to use the aquascape to create some places around driftwood and rocks/caves where the fish can duck out of both current and eyesight from time to time.

I’d also hate to deprive the Harlequin Rasboras of their beloved game of swimming up behind the powerheads and swimming out broadside in front of them so they can kite across the tank. They actually form queues to do this in the current tank. They’ve even taught the Black Neon Tetras how to do it.


I want to cement the end pieces and stands
I would like to save you possible time/money/hassle. I use a ton of (c)PVC in my tanks: any fitting outside or above my tanks gets cemented in place anything inside including spray bars, suction, crossovers, etc does not.

You can usually pressure fit PVC well enough to not leak in tank, and then you can adjust it. Since I tinker on my tanks more than my other toys this saves a ton of time/money on redesign and adjustment since I don't have to try to recreate the whole thing to move one intake strainer 1/4" to stop an annoying noise or twist a rain bar to fix a dead spot.

If you do want to cement it all anyhow, I recommend marker stripes at every junction before disassembly to glue. Remember you only have 15-90 seconds to get the parts where they belong so it's ok to practice assembling the thing a couple times.


Thank you!

I had been wondering, but read that there would be a loss of suction over time if I didn’t cement it.

I may just cement the end pieces so they’re set firmly; the joints don’t potentially break; and I don’t have to worry about the upright parts getting jostled and moved by current, debris, or fish. I’ll leave the long ones uncemented so I can change them out as-needed if I decide to change the powerheads. I can also leave the stands alone or cement an easier to access stem in place that’ll clear the substrate with a coupler for easier access.

I know it’s overkill to paint something that will be mostly buried. Honestly, I only need to paint the end pieces, intakes, stand stems, and anything that will potentially be exposed. The long pieces will never be covered in substrate so I can leave them bare.

Thank you immensely for the input! Definitely gave me food for thought on how to proceed!


Just an update for those interested.

After looking over the pre-cemented pipe I wondered if the Xinyou XY-380 sponge filters I use would fit over the intakes, so I pulled the center columns out and slipped it over; it fit like a glove!

I used the full dry-fit assembly to cement each joint of the end pieces one at a time, pressing it in perfectly in place.

Unfortunately you can see that, as John58ford warned, when using cement, screw ups are forever and I did screw up on one of the couplers on one of the end pieces. I decided I could use this as the end with the power heads and live with the 5/8” difference, as I could easily accommodate for this by cutting stand pieces to different lengths, if-needed.

Here’s the pieces in place with the powerheads and sponges on after cementing but with no cross pieces. Even without the long pieces and suction cup holders for the power heads, everything stayed in place just fine.



I then measured, taped and marked the intake pipes to drill 1/4” holes in them. I cautiously estimated that it would be safe to do 6 columns per intake in alternating patterns of 3 and 2 holes.


I quickly realized I had been excessively conservative, however, and added 4-5 more holes per column for a significantly more open intake.



I then cleaned it and cemented the caps on the intakes, did one last dry fit, then set out to spray paint the end pieces.


By this point I was behind where I wanted to be so I cut a lot of corners when I spray painted which, of course, bit me in the *** when my poorly-secured drop cloth blew over and wrapped around my drying pvc, requiring a lot more work to salvage and fear that it would end up awful.

Fortunately, after some touch ups, it came out better than expected.




Now I’ll be leaving these pieces to cure for the week, apply vinyl to the back and sides of the tank in the meantime, and finish out the inside with new and transplanted substrate and stone and some driftwood next weekend.

This is actually part of a larger project to turn my unused dining area into a work space, which is one of many projects for my week off.

For reference, this is what it looks like at the moment.


As previously mentioned (here? elsewhere?) part of this is replacing the small aquariums that accumulated over COVID quarantine with some larger tanks and consolidating my fish into them. I also plan to take down and store my unused dining table and set up a desk in here.

More to come later!


Not sure if anyone is still interested in this, but more updates, as requested.

This has become a much, much longer project than anticipated, but I think I’m in the home stretch.

So far this weekend, I’ve managed to apply vinyl to the back and sides, replace the airline tubing on the powerheads, as well as the Aquaclear 70 intakes.

As for that last one, I took the intake tubes for 2 sponge filters (same Xinyou ones as before), and worked them into the end of a 3/4” internal diameter vinyl plumbing tube. I then used Loctite super glue to adhere the other end to the intake tubes on the filters. I’m currently giving this time to set.


I’m very pleased with the way the Krylon-sprayed PVC, sponge filters, and vinyl backing all came together. Aside from the unpainted PVC, vinyl tubing, and the clear airline tubing, everything just fades into the backdrop. The former will be covered by the sand and rocks and the latter should be obscured by the fish, plants, rocks, and driftwood in the foreground.

I have pool filter sand ready for a base substrate and will then transfer the existing substrate from my current tank along with the fish and will be placing river rock over that.

I’m considering transplanting my dwarf sword plants, but am not sure if they’ll do well in the fast current or not.

Not sure if I’ll be able to wrap this up today or not. Hopefully soon!

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