Surface crap

[Dtowntrack]

OK so I just did one of my many water changes that I've been doing for a while in an attempt to get my nitrates down. I switched my bioballs to live rock rubble and the trates are steadily decreasing. The water has also gotten crystal clear. However, over the past 3 or 4 days, I have developed a brown, thick, oily, sludge on the top of the water.I've never had this before. Any ideas why I'm getting this stuff? I also moved one of my powerheads to the top of the water to create more agitation, but the stuff just came back.

Paramaters-

Trates- about 15

Trites- .15

pH- 8.2

Alkalinity- 1.5

Ammonia- 0
I've never had this before.

 

[demonsp]

Not enough info to help.
Tanks size?
Stock?
Amount of water changed and scedule?
All equipment used for water flow?

 

[plyr58]

You have a protein skimmer of surface skimming overflow?

 

[Dtowntrack]

Here are my tank specs.

Total system volume 130 liters (34 gallons)
Aquarium volume 110 liters (29 gallons)
Filter volume 20 liters (5 gallons)
Aquarium length 610 mm (24")
Aquarium width 500 mm (19.7")
Aquarium height 500 mm (19.7")
Total height 612 mm (24.1")
Glass thickness 8 mm (5/16")
5 outlet power center
Course mechanical media
Fine mechanical media
Skimmer volume 3.8 liters (1 gallon)
Skimmer pump 1,200 lph (320 gph)
Collection cup volume 1.5 liters (0.4 gallon)
Circulation pumps 2 x 550 lph (2 x 145 gph)
Ceramic bio-media 2 liters (0.5 gallon)
Activated carbon 200 g (7 oz)
Fan cooled hood
Lighting - 10,000K 55W
Lighting – Actinic 55W
Electronic ballast
LED moonlights
24 hour programmable timer
Thermostat heater

I have a royal gramma, 2 false percs, a flame angel, a pink tip haitian anemone, and a BTA. I change water bi-weekly and it's 5 gallons. I also have one of those Koralia pumps that you stick in your tank...don't know the name.

 

[demonsp]

Wow nice list. Does your collectin cup collect?
Do you have a water test kit?

 

[Dtowntrack]

Yea it collects but not a ton. My water test kit is the Red Sea one thatt came w/ the tank.

 

[demonsp]

The koralia pump size would really help.But has is it placed and pointed in your tank?

 

[Dtowntrack]

The koralia is blowing across the top of the rocks, maybe 4-5 inches from the surface. One of my powerheads is pointing directly up and the other one is a rotating flow deflector. I'll try to get Koralia size tomorrow. g2g to bed