Refugium Fed By Dosing Pump?

[deutchriffer]

Wondering if I fed an external reservoir via 2 versa dosing pumps on a continuous water transfer if that would be sufficient water turnover for a refugium, I can run a power head in the refugium if needed, however I am just not able to feed the refugium and overflow it back with the design of my sump, think of this as a remote refugium even though it’ll likely sit right next to the sump.

 

[DanyL]

I doubt a dosing pump, even one made for AWC would be enough turnover for a region to work properly.
It’ll likely quickly bottom out the nutrients and trace elements, and would have much less impact on your tanks parameters.

Most reefers that setup an external refuge use a regular power head.

But it’s just my opinion, I don’t have any experience in practice.

 

[deutchriffer]

Thanks for your reply, just wondering what you mean about trace and nutrients bottoming out?

 

[DanyL]

Thanks for your reply, just wondering what you mean about trace and nutrients bottoming out?

Refugim is usually used with the main goal to reduce nutrients (Nitrate and Phosphate), but it can also almost double the amount of trace elements consumed by the system, and it can get quite aggressive when successful.

Given the low turnover you'll get with a dosing pump, it'll slowly cause a deviation between the nutrient and trace element levels in the tank and the refuge, leading to the depletion of both, and in turn would likely crash the macro algae.

You can probably try to control the growth rate of the algae is such a way that it does not exceed the amount of avaialble nutrients/traces or even dose them directly into the external refuge, however at this point you are somewhat loosing the whole benefit of having a refuge in the system.

 

[Pistondog]

Wondering if I fed an external reservoir via 2 versa dosing pumps on a continuous water transfer if that would be sufficient water turnover for a refugium, I can run a power head in the refugium if needed, however I am just not able to feed the refugium and overflow it back with the design of my sump, think of this as a remote refugium even though it’ll likely sit right next to the sump.

Why wouldnt this work? The versas can dose gallons per day. Nutrients in the fuge will not deplete at that rate.

 

[DanyL]

Because the versa can do only 288L continues per day tops, while even a small HOB refuge comes with a pump rated between 200 to 1000 liters per hour.

It's quite a significant difference.

Maybe for a really small AIO or pico?
But given that OP has a sump, I don't think it'll be applicable here.

 

[PharmrJohn]

I can see the argument here. You will get  some benefit with a lesser flow rate, but it wouldn't be maximized. You could try it and measure growth rate of the Chaeto as well as the effect on parameters, but you'd also need to put in a small powerhead to comparatively measure the difference. But that sounds like an experiment that, personally, I'd avoid, just cause it's a pain in the rear.

 

[Reeferbadness]

I have 2 x 200g tanks both with refugiums. I don't have any extra pump and i have to trim the chaeto regularly - as mentioned in a previous post, macro algae sucks up lots of trace elements + my nitrates go to 0.00. Even trying to keep chaeto to softball size or a little bigger, i have to dose nitrates to keep sps happy. I don't see any need to dose - just a decent grow light should do the trick.

 

[deutchriffer]

Interesting points, I guess I never thought about that just wanted to add a remote fuge

Maybe I’m better off looking at just getting a new sump as it has its quirks overall

 

[DanyL]

Why not giving an algae reactor a try?
It's a closed loop, so you can easily hook up a proper powerhead and be done with it.
Yes, it isn't as comfortable as using a proper refuge, and it has its drawbacks - but it is a plug and play solution.

I also see you're from Germany, you got quite a few brands right around your corner, I would look around to see the avaialble offerings or maybe even a second hand option which would likely be a lot cheaper.

 

[Pistondog]

Put some chaeto in a 5 gallon bucket of tank water and see how long it takes to deplete the nutrients.
Run the experiment.
288 liters is 76 gallons. So some here are saying the chaeto will take the po4 and nitrate to zero in a day?

 

[DanyL]

288 liters is 76 gallons

And 200 to 1,000 liters per hour are 1,268-6,340 gallons per day.

So some here are saying the chaeto will take the po4 and nitrate to zero in a day?

No, that’s not what the claim was about.

A low turnover wouldn’t be able to equalize the nutrient and trace element levels between the system and the refuge fast enough compared to their consumption rate in the refuge.

This means that the longer this setup runs, the bigger the difference will get, and at some point (which depends on the initial nutrient/trace levels, algae growth rate, and volumes) will bottom out.

It can take a day, or 3 or a week - it doesn’t really matter, because it’ll occur quick enough for it to be a problem, and at the same time would not be effective in the main goal that a refuge is usually used for - reducing nutrients in the system.

 

[DanyL]

Put some chaeto in a 5 gallon bucket of tank water

Volumes matter here - if 5 gallons aren’t the end goal, the results will be vastly different as you try to scale it up.

 

[Pistondog]

If the flow coming in from the dosing pumps has more nutrients than what is consumed by the chaeto then it will work.

@deutchriffer , try it, it will work.
VIEL GLUCK!

 

[DanyL]

I like to see numbers, let’s do the calculations.

Assuming 200ml/min flow rate (or 288L/76g per day), and a fuge the size of 10% of the tanks volume (I know there’s no hard rule for volume ratio, but that’s a common practice) and 2-3 turnover requirement to get a reasonable mixing for equalization to occur.

Tank volume: 50 gallons
Refuge volume: 5 gallons
Totals system volume: 55 gallons

1 turnover: 55g / 76g * 24 (hours) = 17.36 hours.
2 turnovers: 17.36 * 2 = 34.73 hours
3 turnovers: 17.36 * 3 = 52.1 hours / 24 = 2.17 days


Tank volume: 100 gallons
Refuge Volume: 10 gallons
Total Volume: 110 gallons

1 turnover: 110g / 76g * 24 (hours) = 34.73 hours
2 turnovers: 34.73 * 2 = 69.47 hours
3 turnovers: 34.73 * 3 = 104.21 hours / 24 = 4.34 days.

Each can draw their own conclusions, but in my very honest opinion I believe that unless the volumes are very low, this approach is deemed to fail, or would rather require quite a lot of tinkering with no significant gain, because the nutrient and trace element levels will have to stay quite elevated on the tank side to keep them high enough for the algae to keep growing.

 

[deutchriffer]

That’s some crazy thought process, good crazy, not bad crazy.

I guess I should give some context as to why I’m asking this question specifically and what someone might recommend instead.

I have an Elos 70, the Elos sump is quite limited in features and space, as you can see from my images I’ve next to no roo for anything, on the left hand side of the sump I’m planning to get a custom acrylic reservoir, and originally I was thinking to have it house SW and run a continuous water change as it’ll be roughly 30-40L but then thought maybe it could be better used as a refugium for pods to breed and some nutrient export as I have a spare tunze eco chic refugium light.

I was planning to sit a couple dosing vessels like the vertex ones, on top of the acrylic reservoir with All4Reef and potentially Kalk or an amino f sorts.

I regards to the algae reactor question, I’ve had a pax bellum in the past and tbh those reactors are more trouble than they’re worth IMHO.

With this extra context I would be keen for some advice