Maybe Roy can chime in and offer some skimmer tips.
He has the C model.
I too suggest the Tunze 3155, I have one, works flawlessly.
And, do you have a powerhead?
I have the Ecotech MP40, works great.
Well here is my take on the C-250 skimmer based on the last 86 days of starting up our tank with no previous experience of reef keeping or protein skimmers.
[My only claim to fame is that [in another life] I was a regular contributing author to Practical Fishkeeping in England]
[In that guise, we kept Japanese Koi Carp and designed and built many large scale water filtration systems to maintain pond water crystal clear and chemically clean whilst housing up to 50 Koi in our outdoor 12,000 gallon ornamental pool].
Preamble
For good Skimmer operation, first and foremost, I believe that you have to have a constant water height in the rear chamber.
The T5 lights generate a lot of heat which requires the water cooling fans to be operational 24/7.
The water cooling fans do their job but the net result is very high daily water evaporation, for us that is about 1 Gallon per day.
The height of the skimmer gate, and the performance of the skimmer, is directly linked to the height of the water in the rear chamber.
Therefore to maintain an effective constant skimmer gate height, the level of the water must also remain constant.
Therefore an ATO is, I believe, mandatory if you are going to achieve consistent skimmer operation.
As I said before I still have the air throttle valve in use.
Our water height on the Right side of the tank is maintained to be only about 1/8" below the very top of the sight window. That is about 7/8" above the water level line.
I could not get the skimmer to skim much protein until I was at Day 21, after that it slowly started to produce the most evil smelling gunge I have ever had the misfortune to dispose of.
Setting The Amount Of Skimming
So how do I set the amount of skimming ?
The gate is set at the very bottom [because I keep the water level is very high]
I then set the air throttle valve closed and slowly open it until the foam shows about 1/2" up into the cup entry tube.
With my water level, if I remove the air throttle valve the cup is filled with water in a very few minutes, no good at all.
With the air valve set and in place, if I raise the height of the skimmer gate, the skimmer quickly over skims and the cup fills with water.
I have no intention of changing the way our skimmer is set, after a week of unattended operation, the cup maybe has a 1/4 to 1/2" of gunge and water in it.
The cup lid, inside and outside of the foam tubes is coated thickly. I remove the cup and scrub it when doing my weekly 10% water change.
Red Sea
Red Sea, state that the air valve should only be used temporarily and removed after the skimmer is broken in.
I expect their instructions are based on the following and they do know what they are doing !
If you maintained the rear sump water level at the line indicated, then the water level would be about 7/8" lower than ours.
In that case, with the air valve removed, and the gate in the lowest position, the skimmer may well operate well and not immediately fill the cup with water.
If that is the case, you would then raise the gate very slowly in small increments so the the foam height was about 1/2" inside the Cup Tube.
It will take around 30 minutes for the foam height to stabilize in height.
So you would need to adjust and then check, adjust again etc so that the foam height is not starting to overflow into the cup.
I do firmly believe that an ATO, such as the Tunze 3155, ensures that you have good and consistent skimmer operation because the water level in the rear chamber will remain at a constant level.
Down the road, when the tank is more mature, I will probably try running the water level down at the water level line.
For the moment though, our skimmer is skimming very well and the whole rear sump system is stable and running great.
Just my 2 cents [or pennies]
Roy
