RO150 tuning issue

[callsign4223]

I have had this skimmer working good for years. Something has happened in the last couple months and it will not function properly. There is a thick buildup of gunk on the neck of the skimmer. If I tune the skimmer wet enough not to get any buildup it is skimming almost clear skimmate. When I first noticed it I had the skimmer tuned normal, water line about 2/3 the way up the neck between the body and the collection cup. The top 4 inches of the neck were covered in a super thick goo. Almost like the foam was too heavy for the skimmer to lift over into the cup.

Things I have tried.

Lowering the skimmer in the water.
Raising the skimmer in the water.
Skimming wetter
Skimming dryer
Replacing the pump, venturi, needlewheel with the one from another functioning RO150
Shortening the output tube(done because my buddy has a RO150 and his tube is shorter than mine. I was basically trying to make mine identical to his.)

At this point I have tuned it so that it's skimming super wet, but I'm only getting buildup on about the top 1/4 inch of neck. This has the waterline about 2/3 way up inside the collection cup.

 

[Vinny Kreyling]

?? I get a heavy coating of "stuff" on mine too, I consider that working & clean it weekly, sooner if water is too high in the cup.
About the only thing I can think of is cleaning the venturi & pump.
I run a proper sized drill bit into the venturi twisting by hand to break up hard salt.

 

[callsign4223]

I soaked mine overnight in vinegar to clean the venturi. The venturi on it now is from my buddies system. His was working properly when he took it off. He removed it because he upgraded his with a jebao DC pump.

If I was getting normal skimmate production I wouldn't worry about it. But all I get is a very small amount of incredibly concentrated skimmate when it's tuned to "Normal" parameters. The thing that really bothers me is that this is a new development. If it had always been this way I wouldn't think twice. But it's like instead of putting the skimmate into the cup its depositing on the neck.

And to be clear, the gunk builds up THICK. Like 1/8 to 1/4 inch thick in a week. It's not just a slime coating on the neck.

 

[Vinny Kreyling]

It still sounds like a "production" problem to me.
Not enough flow & or small bubbles.
A good cleaning of the entire skimmer could not hurt, who knows?

 

[callsign4223]

Is there a way to disassemble the body on one of those to clean the bubble plate?

 

[slief]

How many fish do you have in your system and how large is the display? Has your fish load changed in recent months since the skimmer production started to decline? Have you checked your salinity with a properly calibrated refractometer?

 

[slief]

Has anything else changed in your system in terms of equipment such as reactors, refugium, carbon dosing, UV Sterilizer etc?

 

[callsign4223]

120 gallon display with a 40 gallon sump. Sail fin tang, 2 clowns, Bangai cardinal, 3 Chromis. Salinity is good, checked with refractometer. The only equipment change in the last 6 months is putting t5s over the tank when one of my kessils died. The only other issue I’ve been able to find in my tank is out of control nitrates. Over 100 on a salifert kit.

 

[callsign4223]

So, I had my 5 year old stick his arm inside the skimmer body to clean the bubble plate. Well, as well as a 5 year old cleans anything. I waited a week to give it a real chance. It seems to have helped some. I am still getting the gunk buildup on the top inch of the neck, but now the skimmate is the color I would normally expect.

I'm still at a loss as to how to make this thing run like it used to. But if it works at this level I'll be ok.