Help me make a sump/refugium for this situation!

bang guy

Moderator
The question I was asked was what is a good flow to propagate Harpacticoid Copepods in a 6 gallon refugium. That is the question I answered.
 

seecrabrun

Active Member
Yes.

What would be the solution to give both them and the algae the right flow?

The substrate will be rock rubble only which means in the substrate the flow would be much slower even if in the water column flow was higher.

Would this be a good setup to aim towards?
 

bang guy

Moderator
What kind of algae? Chaeto is going to do better with more flow but most type of Caulerpa will be fine with 8X.
 

seecrabrun

Active Member
I hate chaeto now LOL

I'm trying to pick out all the pieces currently. I have gracilaria and planned to get some other stuff that doesn't need the flow like chaeto or leave tiny floaters everywhere.
 

pegasus

Well-Known Member
Yes.

What would be the solution to give both them and the algae the right flow?

The substrate will be rock rubble only which means in the substrate the flow would be much slower even if in the water column flow was higher.

Would this be a good setup to aim towards?
If the macro algae has good, smooth movement to it, it should be a sufficient flow. Harpacticoid Copepods are substrated dwellers, meaning they will cling to the surfaces of the rocks and glass. I have a fairly strong flow through my fuge, and this allows my Chaeto ball to tumble... yet I see copepods crawling all over the black divider walls. I also have amphipods (quite larger pods) and mysis shrimp breeding in the fuge. I have small stacks of rock rubble in the corners of the fuge, and these are the calmer areas where the pods can breed and lay eggs.
 

pegasus

Well-Known Member
Almost identical
Please don't think I'm being sarcastic, but "almost identical" isn't the same as "exactly identical". My 3/4" PVC overflow handles the flow of a (fairly new) Mag-Drive 3 pump at a height of exactly 4'. Specs for the M-D 3 are 335 GPH @ 3', and 270 GPH @ 5', so if my math is correct, it should be right at the 300 GPH mark. A 1/2" PVC overflow is 33% smaller in diameter, and allowing for the reduction in water weight creating a siphon, you should still have something in the 50% (compared to 3/4") range. 150 GPH is a far cry from 20 GPH.

Did you build it so the bottom elbow(s) were nearly touching the sand? Did you put your "T" at the lowest part of the air tube? Are the two "center" tubes exactly the same length? Did you install a vent tube with check valve on the top elbow(s) to remove all the air? If the answer is no to any of these questions, it won't function at it's full potential.
 

seecrabrun

Active Member
Mine is cream colored with orange glue and is mirrored so the overflow is on the left when on the back of the tank and my T turns to the front instead of the side. And I don't have a red tube to connect airline, instead I put the valve directly in the hole.
Otherwise, identical, minus the fact mine is 1/2" tubing. And my tank is 16" so I cut the pipes to 15" except the one that's supposed to be taller. Then after I put it in the tank I marked the water line and cut that bit off.
 

pegasus

Well-Known Member
Mine is cream colored with orange glue and is mirrored so the overflow is on the left when on the back of the tank and my T turns to the front instead of the side. And I don't have a red tube to connect airline, instead I put the valve directly in the hole.
Otherwise, identical, minus the fact mine is 1/2" tubing. And my tank is 16" so I cut the pipes to 15" except the one that's supposed to be taller. Then after I put it in the tank I marked the water line and cut that bit off.
Okay, thanks. It sounds like it should work, as it doesn't matter which side the drain is on or which direction the tee is facing. I don't understand why you're not getting more flow from it. I'm going to experiment and build a 1/2" overflow this week to see how it performs. I have to finish plumbing mine in today, so maybe I'll get a chance to get on it tomorrow...
 

pegasus

Well-Known Member
I forgot to mention one thing I noticed about priming it... the bottom of the drain has to be under water, and the vent tube (tall pipe) must be sealed off when removing the air via vent line/check valve. This is the only way to remove all of the air. Any air left in the tube will result in low flow...
 

seecrabrun

Active Member
Yeah what I had to do was fill the air tube with a little water so I could get the resistance from both sides to draw all the air out.

I'd very much appreciate it if you could build one and see how it will behave.
 

pegasus

Well-Known Member
Will do. Here's a chart that shows the pipe flow of different diameters. Notice 1/2" PVC has a gravity drain of 200 GPH. Adding elbows reduces this flow, but nothing like the reduction you're getting (20 GPH)...

 

beaslbob

Well-Known Member
I forgot to mention one thing I noticed about priming it... the bottom of the drain has to be under water, and the vent tube (tall pipe) must be sealed off when removing the air via vent line/check valve. This is the only way to remove all of the air. Any air left in the tube will result in low flow...
Needing to have the bottom drain underwater is a function of the design you're using. The "beaslbob traps" here: https://forums.saltwaterfish.com/index.php?threads/the-beaslbob-trap-s.370270/#post-3187264 have a much larger amount of water trapped and therefore all the air can be removed once the trap portion is primed.

You are correct that air bubbles especially in the HOB part will result in lower flow.

my .02
 

pegasus

Well-Known Member
I actually installed a ball valve on the drain (below T) solely for the purpose of priming the overflow... lol! It would have been easier if I could have submerged the end of the drain, but as this is just an emergency overflow and my refugium is 8' feet below and 12' feet away from the tank, I simply tied it into the existing drain pipe. My 40B is drilled with dual 3/4" overflows with gang valves on each to control siphoning. When everything is running smoothly, they work like a champ. When there's a power cut, it takes about 10 minutes before they get "primed" again. I can't figure out why, but that's just the way it is. My PVC overflow is simply there to handle the drainage until the other two catch up.

I was comparing the pictures of "old plan" and "new plan" overflows in post # 9 at https://forums.saltwaterfish.com/t/297623/pics-diy-pvc-overflow, and the only difference is the T is lower in comparison to the original design. If there's a power cut, and having the T lower than the elbow inside the tank, doesn't it create a siphon that empties the lower elbow in the tank and allow air into the top elbow? Just curious...
 
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pegasus

Well-Known Member
I'd very much appreciate it if you could build one and see how it will behave.
I picked up the pieces for the build a few moments ago. Will try to build it to your specs (16" tank, 15" tubes) during my lunch break. $5 is a pretty cheap experiment... lol!
 
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pegasus

Well-Known Member
Okay, I built it and tested it out. I used a measuring cup to mark a jug at exactly 1 gallon... and it took 37 seconds to fill it to that mark. There are 3,600 seconds in an hour, and 3,600 divided by 37 equals 97.30... meaning it drains just a little over 97 GPH.

As time was short, I didn't install a check valve on the top elbow. Instead, I used a pump and a piece of hose almost the same size as the inside diameter of the pipe and pumped water through the inlet pipe. Not sure if I got all of the air out, but I think it was close enough...
 

seecrabrun

Active Member
Weird. I wonder what is wrong with mine.

I will build another one using 3/4" tubing for the 40g I'm upgrading my other tank to. As far as this one goes I said screw it and put an eshopps pf nano on it. I had already bought it but planned to return it. So much about that.

I have everything temp set up and running until I can move my 29 to a 40 and take the stand from the 29 for this setup. Then I'll make everything more permanent inside the cabinet.

Seems to be working fine so far though. It's been like 5 days?
 
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