Skimmer tuning: Coralbox D500 plus

[gugpuccio]

Hi guys,
I know there are tons of threads on how to tune a skimmer. I've read a lot, watched the brs videos on topic and other people's videos but I wasn't able to tune my skimmer properly.
This is my setup: 75 gallon reef tank with led lights and a small "frag tank" in sump, before the skimmer with good flow.

The skimmer is very inconsistent and some days it skims very well and some other days (the majority) it almost doesn't skim. I've tried reducing the dc pump power and reducing the air input but I wasn't able to produce a thick foam on top. The main problem is that bubbles pop at 2/3 inches from the top of the cup and leaves the foam on the side of the final part of the neck.

Can you help me understanding how to tune it correctly? Is the fact that the "refugium/frag tank" is before the skimmer chamber a problem?
The skimmer is set to full power (dc pump) and full air intake.
Thank you so much. I'm adding a small video.

 

[Retro Reefer]

How old is tank? How much bio load? How often do you feed? What depth is the skimmer? How high up the neck do you set your water level?

IMO the 500 is probably on the verge of being to big for a 75 unless its well stocked and also don't be afraid to turn your pump way down, I have to periodically run mine with only 2 or 3 lights on.

 

[gugpuccio]

How old is tank? How much bio load? How often do you feed? What depth is the skimmer? How high up the neck do you set your water level?

IMO the 500 is probably on the verge of being to big for a 75 unless its well stocked and also don't be afraid to turn your pump way down, I have to periodically run mine with only 2 or 3 lights on.

Hi thanks for the reply.
Tha tank is 3 years old, with 13 fishes, I would say medium bioload. I don't overfeed, but when I do I notice a spike in no3 (from 2 to 5/10).
The water level is 20cm and the water height is just below the white support for the air silencer. I've kept it higher and I noticed no increase in skimmate.
I feed twice a day almost only dry food and right now I don't feed corals.

 

[Retro Reefer]

IMO skimmer is way to deep, see picture for my water level.. after raising skimmer use your gate valve to set internal skimmer water level to just at the bottom of collection cup and maybe start at half power on your pump.

My skimmer depth..

use gate valve to set water level in skimmer to here..

 

[X-37B]

I ran a coral box 300 on my 25 nano for 2 years and it was hard to get working right. I raised it up using egg crate until I could run it at full dc power. I dont remember the actual water level but it was around 6" as the sump was at 8".
Check the venturi often. It will clog with salt and calcium and effect performance. I soaked it in vinegar to get it clean.

 

[Retro Reefer]

BTW.. there is a mark on your gate valve for water level.

 

[Bryknicks]

IMO the 500 is probably on the verge of being to big for a 75 unless its well stocked and also don't be afraid to turn your pump way down, I have to periodically run mine with only 2 or 3 lights on.

I agree with this. I'm running a 300 on my 75 system and it is perfect. Anything bigger and would be completely overkill.

 

[gugpuccio]

Guys thanks a lot for the fast and very good answers! My water level is precisely at the optimum mark on the water adjustment screw (I never noticed that mark xD). Do you think I should raise it some more? I will try to turn the pump down!

 

[Retro Reefer]

If you have it at proper water level in sump I would try turning pump down and see if that helps.. its also important to set internal water level correctly.

 

[Bryknicks]

Guys thanks a lot for the fast and very good answers! My water level is precisely at the optimum mark on the water adjustment screw (I never noticed that mark xD). Do you think I should raise it some more? I will try to turn the pump down!

FWIW I have my water level about an inch below the recommended mark, and my pump at half way. The rest is controlled through the gate valve. A this water level it has been extremely easy to tune. I also like to run my skimmate on the drier side.

 

[gugpuccio]

Thanks guys so much. I m raising it by 4 more cm and I will try lowering the power on the pump! It is very reassuring to hear from people who has the same skimmer I will let you know in a couple of hours!

 

[Retro Reefer]

It may take more than a couple hours I would give it some time after you adjust everything, may take a day or two for it to get going depending on how dirty your water is.

 

[gugpuccio]

Hi guys. This is the best I could do. Power setting is at 8/10 dots and I've reduced the air intake a little bit by using a tube that goes outside (to maintain a higher PH). How does it look to you? It's not skimming a lot but the kind of foam it produce seems correct. This is a 15 hours skimming.

 

[Bryknicks]

Hi guys. This is the best I could do. Power setting is at 8/10 dots and I've reduced the air intake a little bit by using a tube that goes outside (to maintain a higher PH). How does it look to you? It's not skimming a lot but the kind of foam it produce seems correct. This is a 15 hours skimming.

That looks good to me.

 

[ksed]

Hi guys. This is the best I could do. Power setting is at 8/10 dots and I've reduced the air intake a little bit by using a tube that goes outside (to maintain a higher PH). How does it look to you? It's not skimming a lot but the kind of foam it produce seems correct. This is a 15 hours skimming.

Is you outlet of the skimmer all the way open?

 

[gugpuccio]

Is you outlet of the skimmer all the way open?

The water outlet is 2/3 closed and the air is full open. I only have a tubing that goes outside for the air intake that surely add some resistance.

 

[ksed]

Ok , I see an issue. Always start with outlet wide open.
What depth is the skimmer at?
Try this: Open the outlet all the way
Next : Increase your speed in the skimmer one light above your current setting.

I believe you are two lights down from full speed?

 

[gugpuccio]

Ok , I see an issue. Always start with outlet wide open.
What depth is the skimmer at?
Try this: Open the outlet all the way
Next : Increase your speed in the skimmer one light above your current setting.

I believe you are two lights down from full speed?

Thanks, yes 2 lights from the max. My water height is at 6.5 inches. So should I completely open water outlet and start increasing power? But the bubbles stops very low in the neck like that!

Anyway I've tried to open completely the water outlet and water is not rising. It makes bubbles for a couple of inches above water level. Is it normal?

 

[ksed]

Thanks, yes 2 lights from the max. My water height is at 6.5 inches. So should I completely open water outlet and start increasing power? But the bubbles stops very low in the neck like that!

Anyway I've tried to open completely the water outlet and water is not rising. It makes bubbles for a couple of inches above water level. Is it normal?

Keep the out let all the way open and turn power all the way up.
Let it stabilize for a few hours.
Then start closing the outlet until the desired water or foam height.
With full power you may have to close the outlet at halfway, but do it gradually just in case you may not need to go that far.

Also anyway you can increase water level in the sump another inch?

 

[gugpuccio]

Keep the out let all the way open and turn power all the way up.
Let it stabilize for a few hours.
Then start closing the outlet until the desired water or foam height.
With full power you may have to close the outlet at halfway, but do it gradually just in case you may not need to go that far.

Also anyway you can increase water level in the sump another inch?

Yes i could. I tried raising the skimmer because I had 8 inches one week ago! Do you think it's best?