How accurate is manufacturer's rating for skimmers

[weileong]

Was at EAN this afternoon to collect my deltec stuffs and happen to meet a gentleman who has upgraded to the deltec AP702.

His old skimmer was certain german brand skimmer.

No brands is mentioned here but the height of the specs of the skimmer is:

Height: 590mm

Main chamber diameter: 110mmm

Rated for 500-1000 litres.

The gentleman had a 5ft tank so we assume a volume of 180 gallons = 600 litres. This is well within the rating of the skimmer.

His tank has an outbreak of red hairy algae which cannot be solved. Bioload wise, mostly SPS and only 1 kole tang. Based on this, if we follow the manufacturers' rating strictly then his old skimmer is consider good and in fact slightly over specs for his reef tank. But why in this case algae outbreak?

Skimmer brands aside, the specs his new skimmer is as follow:

For Aquariums up to:

Heavy Stocking 1500 Ltrs (333 gals)

Normal Stocking 2000 Ltrs (444 gals)

Height: 610mm

Main chamber dia: 250mm.

See the height diff is neg but the volume of the main chamber is 5x more yet the rating is just 2x more.

Any thoughts on this?

[iori_del]

i am newbie here, but just to check wat the pump used? same??

[weileong]

Solely based on manufacturer's rating. For similar specs

Example Deltec AP1003, roughly same rating as Bubble King 300 but AP1003 running 3x1260 while bk 300 running 1 red dragon needlewheel.

For this example we trust both manufacturer's rating.

[roidan]

tat's why i always say....manufacturers guides are just a rough starting point....

if u buy a skimmer and its published capacity is already many times more than your water volume and YET you still have residual nitrate problems and other problems....it just means that you need to move on to a better one. (unless you are happy with the high nutrient levels and want to keep it that way)

I am glad this new owner of AP702 has learnt that his previous GERMAN skimmer cannot handle his application context and decided to change for a better skimmer in the AP702, instead of applying blind faith and stick to his previous skimmer (and its ratings).

If the AP702 still cannot solve his issues, simple, it doesn't mean AP702 is a bad skimmer. It just means it is not good ENOUGH for his application context.

[weisoon]

Royal Exclusiv has revised their AIR rating from the Red Dragon pump of Bubble King External 300. Due to too high air input causing the skimmate to be too wet. Also heard that the flow of the pump is also reduced. Heard only ah......maybe someone can comfirm?

[roidan]

actually i find that if they have to throttle back the pump, it is really such a waste.

I wonder why they rather handicap the RD instead of using bigger/taller chambers to accomodate the high air/water flow...but probably that would mean even higher prices

[weisoon]

Previously spoke to Klaus on the phone and he mention a few improvements on the BK300 external which will be sold standard with the following improvements:

100cm total height

diameter same

calcium by-pass

drain on the collection

bigger red PVC pipes

Bigger diffuser plate

change in position of pump's inlet to skimmer body

new silencer

Something else to add for discussion:

Does too big a riser tube's diameter affect the type(wet/dry)/quality of skimmate?

[roidan]

wow....1m tall now for the bk300...

now we are talking

seriously i felt the super high air/flow of the RD is actually quite disruptive in the relatively short chamber considering the prowess of the pump...but when the new batch of 1m tall bbk300 comes in....one will definitely notice that the added height will tame down the bubble dynamics. i actually suggested to a friend to chop off the existing short chamber and add a middle extension to increase the height, but definitely will affect resale value. But now that RE is actually doing the increase chamber height (hope not bundled with increase price ), it's definitely good news for new buyers

talking about riser tube...definitely small or big a reduction will have an effect....but i haven't experimented with too many sizes myself. maybe those who DIY skimmers in bulk may have tried with different riser diameter sizes and can contribute to this aspect.

from what i notice, if the foam is not massive and "powerful" enough, it will have a hard time ascending a wide riser.....i think maxima has mentioned before.....small riser necks are to aid the climb of foam for underpowered skimmers that need the pressure difference to push the foam out into the collection cup....but actually all skimmers need this slight change of diameter to aid the foam push, only a matter of how much....

but to address your question...i think if the skimmer's foam is not ommph enough, a wide riser neck will result in a tough time for the foam to rise and may result in very dry skimmate and very dirty inner necks....but then to raise the water level and thus raise the foam probably can get past this...

on the other hand if the riser neck is too narrow, the foam will be pushed out very fast and skimmate will be rather wet generally unless the user deliberately lower the water/foam level and get dryer skimmate...

but there are some skimmers whereby somehow the user die die cannot tune the range of skimmate from wet to dry and is limited to either wet or dry skimmate...

well...just my observation so far

ps: but anyway we can think of the riser tube like an exhaust pipe....if the engine exhaust(foam) is alot and powerful...need a bigger pipe so that it doesn't bottleneck the system.

[weisoon]

Agreed on mostly what roidan mentioned. But have something to add:

If one look at the very top of a rising foam head, the bigger sized bubble will 'connect' together to form a matt and the will will rise up the riser till it reaches the rim of the riser and then breaks. When it breaks, the foam will then fall over into the collection. Base on this theory, due to surface tension, if the riser tube is too big, there will be problem for the bubbles to stick together into a layer then rise up the tube. More often than not, the bubbles at the top will grow due to the bubbles at the bottom pushing and merging them and then getting too heavy for surface tension to hold and then breaks prematurely.

I have seen small riser tube size (small skimmer)and really surprised to see a thin layer of foam rising and travelling more than 3 times the diameter of the riser tube up from water line to edge of riser tube. And this foam will travel up in individual layer up maybe every 5-6 seconds. Quite interesting.

So.....does surface tension of the foam layer theory applies here? If it does, by creating more surface area in the riser tube help the foam to hold tension and thus stable rising foam till the rim of the riser?

[roidan]

i think it's a balance of the foam thoroughput and the diameter of the riser decided by the manufacturer, when he knows the kind of foam his skimmer will render....

the surface tension also plays a part when the foam rises to the top edge and when the matt spills over, it pulls along the next layer and so on...

the thin layer that you observe is like thin layer slowly *floating* up instead of being pushed up by a thick cushion of foam underneath it right? hehe..yeah...quite interesting...

like the premature bursting of bubbles u have mentioned besides the thick matt of foam that eventually spills over in the collection cup...even if we assume the burst results in spitting of the organics in multi directions...it will probably land directly overhead underneath the cap, the sides of the cup that often prevents us from seeing into the cup clearly, or even spits itself back into the thick cushion of foam underneath it that is ascending the riser....so it may not be such a big problem...

personal opinion lah....hehe

but anyway hor...we abit off-topic liao lah..this thread is about manufacturers ratings

[weileong]

Just got the updated info from the reefer who upgraded to the AP702.

Here's what he said.

Just fire up my AP702 skimmer this afternoon. Bubbles are very fine - finer than my XXXX-XXXXX brand germany skimmer through ###### eye.

[andysho]

hmm maybe i can consider deltec skimmer

kekek

weileong can i drop by one day and look

at this skimmer live performance?

[hamannbmw]

hmm maybe i can consider deltec skimmer

kekek

weileong can i drop by one day and look

at this skimmer live performance?

front row $80/per head, middle row $50 and last row $30... children under the age of 12 50% discount....... show time ask WL ..lol

[weileong]

hmm maybe i can consider deltec skimmer

kekek

weileong can i drop by one day and look

at this skimmer live performance?

Can lar, arrange with me