Crazy plumbing question

[returnofsid]

Alrighty, bare with me, as this may be a bit confusing to type, probably even more so for those of you reading...lol.

I'm setting up a 200 gallon Marineland Deep dimension, dual corner overflow, with Starphire front glass.

In talking with the owner of the LFS where I purchased this tank, and then another hobbyist who recently set up this same tank, we came up with an idea, that seems crazy, at first...but more feasible, the more I think about it.

The overflows come with Marineland Dursos and returns, 1 Durso and 1 return for each overflow. The overflows also have a removable "plate," at the front, that has a "grill" cut into the bottom of it, and a grill cut into the top. The top grill works as the overflow preskimmer. The bottom grill has no purpose that I can see, as the are no holes behind it......yet!!! Oh boy, I can see this is going to require pictures.

Here's a picture of the overflow, front plate installed.


Front plate removed and plumbing setting in place.


Front plate.


So, here's our thoughts, yes, Barbie's included in this possibly insane idea!!!

One of the overflows will serve as a typical overflow, as designed, draining to a sump/refugium and then returning.

The other overflow will be modified and used as a closed loop feed. Here's the plan:

Remove the plate and drill 2X 1"-1 1/4" holes in the overflow, in about the area of the lower "grills." The removable plate will be reinstalled over these holes. These new holes will then be plumbed to the bulkheads, using spa flex. PVC would be used from the bottom of the bulkheads onward... This will give me 2X1" lines, draining out the bottom of that overflow. These 2X1" lines would be combined, using a Y, into a single 1 1/2" line, which would feed a large pump, like a Dolphin 3000/4000. The output of the pump would be 1 1/2" or 2". The output would be split into either 2 or 4 return lines, which would return over the back. My first thought, is 4 return lines, 2 feeding 3/4" Seaswirls and 2 feeding 3/4" locline with penductors. Each return line would be plumbed with a ball valve, to fine tune flow. Ball valves would also be plumbed before and after the pump. I wouldn't even need the spa-flex, if I just stubbed 1" PVC a couple of inches out of each bulkhead and screened the ends off. This would enable all of the water in that overflow to be turned over quickly. It would also enable me to cut more, or larger holes, behind that cover plate.

This would give me one overflow that's plumbed to the sump/fuge and the second overflow being modified for the closed loop.

My original concern was that the 2X1" lines would limit me to only about 1200 GPH of flow. Then it was brought to my attention that the 600GPH per hole, represents gravity flow, NOT flow forced by the large pump.

Soooo, does any of this make any sense at all??

[Ninong]

I don't think the two 1" lines would be adequate to supply water for a Dolphin Ampmaster 4000/3000 pump used in a closed loop system. That pump produces 4,000gph at 2 ft using a 2" outlet and more than 3,000gph using a 1.5" outlet. Yes, you can dial it back but the point is that this pump would be way, way too much for your proposed intake.

In general, the intakes for closed loop systems are located higher in the tank than the location you are considering. In general, the intakes are capable of supplying double the amount of water needed by the closed loop pump. That's because you don't want your intakes creating a vacuuming effect on anything passing near them.

Even if you dial your pump back substantially, you would probably create a tremendous sucking current at the bottom of your tank that would be enough to draw sand, creating a sand dune that would build up against the intake area.

Check around the other Marineland products and you will probably find that they (under other brand names) have used that sort of double intake corner overflow compartment (without the backing) as part of a different sort of return system. It was closed off for this tank series because this is a different return system.

Your idea might work if you were planning a very, very low flow closed loop system. Extremely low flow. Even then the intake would be located much lower than most closed loop systems I have ever seen. If you try dialing up the intake, you will probably end up having an anemone, or something similar, stuck up against the intake grill, closing off the flow to the pump.

[returnofsid]

Now, instead of plumbing the holes I'd drill to the bulkheads, if I were to just drill the holes, cover them with the removable cover, and stub 1" PVC out of the bulkeads an inch or so, it would allow the pump to be supplied by the water in the display, as well as the water in the overflow, with approximately 25" of water above it. Directly under the bulkheads, the 2X1" lines would converge into a 1 1/2" line, via a Y. (WOW that first sentence is LONG)

Do you see this improving the problem with suction being created directly outside the lower grate of the removable cover? This would allow the water in the diplay, AND the water in the corner overflow to supply the pump.

In speaking with Spokane Pump, this morning, the tech seemed to think that this design would allow the pump to push at least 3000 gph of flow, without any cavitation issues. I plan on calling Dolphin in the morning and speaking with one of their techs.

[Ninong]

I'm going to ask Rocky (scubadude) to respond to your questions because he has experience setting up closed loop systems.

[returnofsid]

Thank you Ninong. My only hurdle is finding out if the 2X1" holes, in the bottom of the tank, can supply enough water to keep the back end of the pump flooded, to avoid cavitation. I'm willing to throttle the pump down, some, if needed. However, if I have to throttle it back too far, this project won't even be worth it, and I'd go with powerheads in the tank instead. If that were the case, both corner overflows would be used as designed, returned through penductors, and I'd probably use 4-6 Modded MJ1200s on Suregrip mounts.

[Ninong]

I'd probably use 4-6 Modded MJ1200s on Suregrip mounts.

OMG, No!

Go with either Ecotech Vortechs or Tunze Turbelle Stream 6105's. The Turbelle Streams (with or without the controller) are top-of-the-line but a little pricey.

Don't go with MJ 1200's. They don't move any water at all compared to the 3,170gph you can get out of each Turbelle Stream, and their output is adjustable. For your size aquarium, two Turbelle Stream 6105's would be perfect and much, much better than half a dozen MJ1200's.

[returnofsid]

My first choice would be to go with this closed loop, IF it'll work. If not, the problem is that I have to think about the price...lol. Two Turbelle Stream 6105s would run $650.00!!! Granted, each would give me 3,434 GPH. However, for about $50.00 each, I can get Modded MJ1200s with Suregrip mounts, that will each give me 2200 GPH. The Vortech MP20 would run $300.00 each and give me slightly less flow than the MJMods. For the price of a single MP20, I could be running 6 Modded MJ1200s and getting 13,200 GPH. The Modded MJs are also "aimable" on their swivel mounts. As far as I know, Vortechs are not.

That being said, I do like the ability to adjust and program the Vortechs, with the controller and I love the battery back up option, but I just can't justify the cost, unfortunately.

I hear some people talk about how the Modded MJ1200s only last a year or two. I purchased 3 of them, used, over 3 years ago. The previous owner got 3 years of continuous use out of them. They've been running trouble free for me since. So, that's at least 6 years of service. I have a 4th one that was also purchased used. The end of the prop shaft recently sheared off. Shureflow sent me a replacement free. I have no idea how long that one was in use before I purchased it, but I ran it for 2 years.

Another option I've been knocking around, is to use both overflows, as designed. Use the large external pump as my return and return through the 2 overflows, with penductors, as well as 2 3/4" seaswirls. The Dolphin Ampmaster 4700/5600 can be throttled down, without injury to the pump, and actually draws less amps as it's throttled back. I would also have the ability to divert some of the flow back to the skimmer area of the sump. I realize this is vast overkill for this idea, but I would be getting the Dolphin AM 4700/5600 for $150.00. That's a price that I'm finding it hard to turn down...lol.

[returnofsid]

Well, I just got off the phone with Dolphin Pumps, where I spoke with a Tech and the owner. They both seem to feel that the 2 1" lines will be able to keep the suction end of the pump flooded just fine. They even make a 2X1" - 1 1/2" manifold for just this type of application. They also suggested that I increase from 2X1" - 1 1/2" - 2" as high as possible and then continue the 2" feed down to the pump. Output would go from 2" to 1 1/2" manifold immediately. From the 1 1/2" manifold, my 4 returns would be 3/4".

[Ninong]

You probably spoke with the owner's son.

[Ninong]

How are you getting that pump for $150.00? Are the seals saltwater safe?

[Ninong]

I don't know what happened to Rocky. Maybe he's on vacation or something.

[returnofsid]

It's a used pump, with a known history. Yes, totally saltwater safe. Screaming deal and hard to pass up. This is why I'm tying to figure out a way to use it...lol.

[Ninong]

I sent Rock a PM a few days ago asking him to chime in but apparently he's off on vacation somewhere because he hasn't responded.

I will summarize my advice as follows: Your plan is seriously flawed on several points. If you proceed with this idea of using two 1" intakes at the bottom of the corner overflow compartment to feed a gigantic Ampmaster pump, you will be VERY disappointed.

I don't care what advice you got from the LFS or from the guy at Dolphin, you cannot set up a closed loop unless the intake(s) provide at least 1.5 times the pump's capacity, although double would be better and is what most people shoot for.

You cannot set up your intakes in the bottom of the corner overflow compartment without causing serious problems with the functioning of the corner overflow compartment.

I belive I have already made those points earlier in this thread but you have decided that they don't matter.

I wish you luck. You're going to need it.

[returnofsid]

Ninong, where are you getting the idea that I've decided that your points don't matter?

I've asking for advice from several different forums, on this subject, as well as speaking directly with more than 1 pump manufacturer and pump specialty wholesalers.

I haven't made any decisions yet. I haven't drilled any holes, or done any plumbing. I'm waiting and "pooling" all the resources and advice I'm being given, so that I an make an informed decision. I do believe, that at least in some areas, no single person is an expert on ALL things. So, the more advice I get, from the largest pool possible, the most informed decision I'll be able to make.

Ninong, I do highly appreciate your comments and advice, however, I don't appreciate people making assumptions about how I feel towards advice I've specifically asked for...lol.

Once I feel I've got enough advice, with a specific "leaning" one way or another, I'll make my own informed decision. I'll also keep everyone updated!! Thanks!!