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View Full Version : BK Double Cone 180 inconsistency as time passes after cleaning


camaroguy
08/24/2016, 01:16 PM
Hi,

I have a BK Double Cone 180, and I find that I have to consistently monitor the speed of the pump to get a consistent skim. It seems that as the pump gets dirty it continuously slows down, though its never "that dirty".

As soon as I clean the pump (take it apart and clean all the parts), I have to set the speed WAY down or it will just overflow in a few hours. As time goes on I have to bump the speed every couple of days to get a consistent skim. Whenever I do clean it, it isn't very dirty at all, and there isn't every any calcification.

It has been this way in the 1.5 years I have owned it, but lately I have been trying to keep my nutrients at a precise level with carbon dosing and such...so its become more of a hassle.

Is this normal behavior?

slief
08/24/2016, 06:54 PM
What speed are you running it at? Also, what size display do you have it on and what is the load like in terms fish count and fish size? How often are you cleaning the pump? Are you inspecting and cleaning the Venturi port on the nozzle to remove salt creep? The nozzles on these pumps are held in place with an o-ring to make cleaning the nozzle easy without having to remove the pump let alone having to take it apart. Salt creep will impact the skimmers performance. I try to clean my Venturi port about once a month to remove any salt creep. I clean my skimmer pump every 3 to 4 months taking it completely apart and giving it a short soak in vinegar followed by a good scrubbing and rinsing. The whole process takes me 10-15 minutes but my nearly 2 year old pump still looks like brand new because of the routine maintenance.

FWIW, ideal speed for the DC 180 is between 18 and 24 watts depending on the load.

camaroguy
08/25/2016, 12:43 PM
I estimate there is about 135 gallons of total water in the system. I run the pump anywhere between 22 and 40 for the settings. I think that works out to something like 24 and 38 watts (over a ~2 month range).

The fish load is as follows:
1 9.5" Powder blue tang that eats A LOT
1 4.5" Clown fish
3 3" Green Chromis
1 1.5" Yellow tail Damsel

I used to clean the pump every week, so I didn't have to adjust the speed so often...but that got tedious. There is never any calcification and its not even that dirty, just a small bit of a film on things.

Since I am carbon dosing I have to skim fairly wet to pull the bactieria from the water. My pump too looks mostly new after I clean it. At the lower wattages you mention, I can hardly fill the cup with in over a week's time.

At this moment the skimmer body is pretty dirty toward the top of the neck. This is because during certain times of the day the foam level can drop a lot, and the bubbles pop inside the neck. Usually when I feed.

slief
08/25/2016, 01:47 PM
I estimate there is about 135 gallons of total water in the system. I run the pump anywhere between 22 and 40 for the settings. I think that works out to something like 24 and 38 watts (over a ~2 month range).

The fish load is as follows:
1 9.5" Powder blue tang that eats A LOT
1 4.5" Clown fish
3 3" Green Chromis
1 1.5" Yellow tail Damsel

I used to clean the pump every week, so I didn't have to adjust the speed so often...but that got tedious. There is never any calcification and its not even that dirty, just a small bit of a film on things.

Since I am carbon dosing I have to skim fairly wet to pull the bactieria from the water. My pump too looks mostly new after I clean it. At the lower wattages you mention, I can hardly fill the cup with in over a week's time.

At this moment the skimmer body is pretty dirty toward the top of the neck. This is because during certain times of the day the foam level can drop a lot, and the bubbles pop inside the neck. Usually when I feed.

The load is pretty light so there isn't all that much in the way of dissolved organics. The skimmer will remove the DOC's quickly and then idle along until the build back up resulting in somewhat inconsistent performance.

At the lower speeds, you gain contact time which results in better skimmer performance. You would need to increase the water level in the skimmer though to maintain the wetter skim which would require raising the sump level or closing the wedge pipe more. I don't suggest closing the wedge more than 50% though. You are aiming to get the line where faster moving bubbles transition to foam up to just above the threaded collar where the collection cup meets the body. That would be your driest setting. From there you can use the wedge pipe to wetten the skim. I would suggest lowering the pump speed down 20 watts and raising level inside the skimmer.

camaroguy
08/29/2016, 12:51 PM
I wasn't actually able to get the bubble transition line that high. You can quickly get in a situation where the air tube is no longer able to get air because of water level.

I have the transition set about .5" below the collar for the moment, and the pump set at 20W consumption which works out to a setting of like 14 or something. It is skimming somewhat wet, so far. I will keep an eye on it and see how it does for the next few days.