Skimmer physics related to SG

[dakar]

Okay folks, help me understand this, as for some reason it seems backwards to me.
Same skimmer (Jebo 180, efficient enough to work well for a FO tank) has been running on the new 29 for a few days, SG @ 1.023, works just fine, produces about 1/2 cup of medium skimmate over two days.

Decided to clean the collection cup and stuff out today and figured while I'd had it apart wanted to see how well it would do on the 180, SG is @ 1.029 (raised SG to see if it'd help settle the sand storm faster, actually helped a bit), but with the higher salt concentration the skimmer after only an hour i checked on it and she had filled the collection cup up, mostly just water, foam was very thick, heavy and very unmanageable as to height, would need to add some flow restricter to make things manageable.

Now to the physics part, why? In FW of course you get no foam production, observed while topping off the sump with FW the Berlin skimmer levels drop off dramatically until the water is thoroughly mixed, then 10 mins later back to normal. I know that its the SW that allows for the foam production, I'd have thought at least to a degree since the water is actually heavier at higher SG, at some point in concentration it should impede the efficiency of the pump and then in the reaction chambers.

Anyone do any further experiments for these observations?

[ereefic]

Is it an in-sump skimmer? Not familiar with it.

[dakar]

Now the one I was playing with is a HOT, only runs an 1100 liter/hr (whatever that equates out to in real gph), for a simplistic design its pretty effective, I didn't want to have to build a sump for this tank as it will have macros and stuff in it.

[ereefic]

I was curious because if it is a in-sump model, there would be too many variables to say it was or wasn't the salinity at work.

Physics? Got me. :)

[Reptoreef]

I
Physics? Got me. :)

Ditto... :-| ... it does kinda make sense, though.

[dakar]

makes sense, but in a backwards sort of a way, thats way I was looking for an in-depth reason to explain it.

Kinda along the same lines as GT's idea to run SG up near 1.030 to calm the initial sandstorms way down when setting up a new tank, it works, what used to take a week or more now settles in under a day. But I'll be dipped if I understand the WHY's.

We need to recruit a rocket scientist or at least someone who played one on TV to help answer these kinda questions.

[davejnz]

That kind of reminds me of boating.When in saltwater,your boat is alot more bouyant than when in freshwater.Must have to do with the density of the water.Wish i could expain,need to go read a science book.

[jerryc]

Physics?

Gives me a headache :shock:
been a long time sense i studded physics in school :-)