Durso to herbie conversion issue

[ca1ore]

Actually they will. Since the DT has the same level the overflows maintain the same level(or would if the overflow grate wasn't so restrictive). Balancing the flow is no harder than if they were in the same one(again if I didn't have a bottleneck at the grate). The earlier mention of stagnant water in the overflow with only the trickle is a valid concern though. Balancing dual full siphon pipes seems like it could be a little tricky, but if people do it, it must be possible.

I tried many combinations and permutations with my ML265, and ended up doing dual herbie because none of the other ways worked to my satisfaction. If you get what you propose to work I'd be curious to see it working (or not working as the case may be). The problem with having essentially all the flow through just the one corner is actually not stagnation, rather lousy surface skimming. Perhaps less of an issue with a 4' tank, versus 7', but I'll stick with my assertion that it cannot be done .... properly.

 

[fermentedhiker]

i would use one pump and a splitter to both returns. even with head loss you should have plenty of flow.

I like using dual return pumps for redundancy. That way if one fails I've only lost half my flow but the entire system will be fine and never miss a beat compared to having a single one die and having the sump cut off from the tank until I get home at night to swap out a spare. I'll try valving these ones down and see how it goes. Originally was looking at a couple varios pumps(from the BRS ULM series of videos) but decided to save money by just using the pumps he gav

They are independent and won’t balance properly. As soon as one has an issue ( snail on the drain) you are going to have a flood. The open channel needs to handle the full flow. You are telling us that it can’t even handle half the flow. What do you think is going to happen if one side has s problem?

They are not independent. period. They can more than handle the full flow. It's just the weir that can't. No flood will happen as the weir is slightly below the rim and so would be overtopped before the tank itself could overflow.

 

[fermentedhiker]

I tried many combinations and permutations with my ML265, and ended up doing dual herbie because none of the other ways worked to my satisfaction. If you get what you propose to work I'd be curious to see it working (or not working as the case may be). The problem with having essentially all the flow through just the one corner is actually not stagnation, rather lousy surface skimming. Perhaps less of an issue with a 4' tank, versus 7', but I'll stick with my assertion that it cannot be done .... properly.

It's a 6' 125 to be clear. It seem to work fine at the moment at half flow. Which may be plenty for the tank. You may be right about surface skimming inefficiency although to be honest I'm not sure if two corner overflows to a great job of it anyways. My 90 Gallon peninsula is essentially a coast to coast and none of my other tanks come close in terms of surface skimming, but that was a custom tank not the more budget conscious build this is. Didn't feel like going all out on a softie/lps tank. Still debating on going with a dual herbie and returns over the back. I may have found a good source for a couple sea swirls to make the return flow more random which would lead to an improvement on both fronts. Just ups the cost of the build.

 

[Flippers4pups]

So one side is the drain and the other is the emergency. Two return pumps feeding the main drain., Right?

 

[lmm1967]

I like using dual return pumps for redundancy. That way if one fails I've only lost half my flow but the entire system will be fine and never miss a beat compared to having a single one die and having the sump cut off from the tank until I get home at night to swap out a spare. I'll try valving these ones down and see how it goes. Originally was looking at a couple varios pumps(from the BRS ULM series of videos) but decided to save money by just using the pumps he gav


They are not independent. period. They can more than handle the full flow. It's just the weir that can't. No flood will happen as the weir is slightly below the rim and so would be overtopped before the tank itself could overflow.

Ok. Have at it then.

 

[maroun.c]

That's too much flow and even if u manage to work out the flow capacity issue in the weir it's more likely to cause splashing and a noisy sump with more salt creep. I'd dial them down or change them to smaller ones.
I alwaysake my overflow screen removable for easier cleaning so when I faced similar issues I just had one with larger openings made, looks neater
If u can deemed them clean enough that should do it as well.

 

[fermentedhiker]

So one side is the drain and the other is the emergency. Two return pumps feeding the main drain., Right?

Essentially yes. The emergency is taking a small amount of flow all of the time so it's not like a dry bean animal emergency but if I plug the full siphon drain it takes over(with a lot of noise). It's working mostly fine ATM at half flow. My full siphon standpipe is a little to close to the surface and so periodically creates a tiny whirlpool and sucks air but cutting the standpipe down will fix that if I stay with this setup. Still thinking about doing the dual herbie as has been suggested.

 

[jcl123]

I think I see your problem, and why you think the weir can't handle it, because it probably can't.

Take a look at my post here at the bottom of this page: https://www.reef2reef.com/threads/herbie-vs-bean-animal-is-bean-animal-worth-it.472834/#post-5223851

I don't know if my weirs are exactly like yours or not, but mine were still doing OK at 1,700 GPH (that's the two combined, so that is about 850GPH each....) The original "megaflow" specs say 600GPH, and I think that is each. But probably that was more about the durso used than the weir. I stopped at 1,700 because that was both pumps full blast. But I also think I was right at the limit of what the weir's could comfortably do. I think a little more and it would have been going over them, which would not have been a comfortable water level for the tank.

Let's say each of your pumps is conservatively doing 500GHP after loss, you are still 250GPH past what I am doing, so I am sure it looks like it can't keep up with just one weir. Is the water actually going over?

As others have said here, I would use both Weir's the same way, not try to use one as primary, and one as secondary. I think the only way that would really work well is if one was actually taller than the other. Or, as you stated, cut more/larger holes in the weir (just the one that is primary). But I agree there is a high risk of a ghetto result with a dremel. I am probably going to leave mine alone and just dial back to about 1,400GPH, which is my 10x Triton goal anyways.

Also, the other problem with the primary/secondary idea is that you won't get enough flow through the secondary and risk having stagnant water there. Standing water is bad.

So, my suggestion is you have two full siphons using the 3/4" pipes, and use the 1" pipes as your emergency backups, and run the returns over the rim of the tank.

-JCL

 

[ca1ore]

It's a 6' 125 to be clear. It seem to work fine at the moment at half flow. Which may be plenty for the tank. You may be right about surface skimming inefficiency although to be honest I'm not sure if two corner overflows to a great job of it anyways.

Corner overflows generally suck, that's true. I hated them on my 265. What an improvement on my now 450 with a ghost style unit; though I appreciate the desire to not pump up the cost. I ran a 6' tank years ago with just a single corner overflow (it was a custom tank before the advent of mass market reef ready tanks). Surface skimming was lousy and I had to use a sea swirl to move water from the distant end.

 

[ReefHog]

 

[fermentedhiker]

I think I've made the decision to do the dual herbie. I got thinking that once the display fuge is up and running(it's around 55 gallon and will empty into the DT that I'll need even more flow over the overflow so it would be better to have both of them working at capacity instead of one. Next decision will be how to bring the returns over the back.