surface skimming

[MikeyZO]

So I've been getting an oily film buildup on the surface of my water. So last time that happened, I skimmed the water off the surface and did a wc, and also cleaned out the detritus from my sump (I dont have a filter sock *sigh*) and voila, it was fine. So I'm getting that oily build up again, which tells me its time to do a sump cleanup again. So I did, changed 10 gallons (5 from sump and 5 from DT while skimming the surface). But this time the build up is still there. So this is a two part question.

a) is it possible that my internal box of my external overflow has gotten dirty enough that it isnt skimming the surface properly and requires a cleaning, and

b) does anyone else use and have a problem with clear vinyl retun hoses where all crap just sticks to the inside of it and you have to change it periodically?

 

[mray]

Have you changed return pumps recently? If so, the return pump you have is probably pushing more flow than the old one but your overflow is not draining any faster. If you have a durso with an airline tube in it, try to block the hole a little to cause your overflow to drain faster. That should solve your problem.

 

[MikeyZO]

I'm assuming its not a durso (not exactly sure what they are) because it doesn't have an airline tube in it. This is the overflow I have:

http://www.aquabuys.com/page/aqb/PROD/pca_pre-overflow

 

[mray]

What return pump are you using? An oily surface is due to having more flow returning to your tank than your overflow can handle. I had the same problem a long time ago and I couldn't figure it out until I realized that the water was not returning the the sump fast enough to carry the surface film. I corrected my problem by adjust the amount of air in my durso. What you have is an external overflow. I don't know if you can really do anything besides throttling down your return pump.

 

[MikeyZO]

well I took the box out and cleaned it very well and then put it back. Believe it or not, its running much better now and the oily film was gone within an hour. So I guess small amounts of algae in the teeth of the overflow can cut the water flow down.

Good to know.

 

[daaznmofo]

can you clear out the stuff in the clear tubes? i have clear tubes and have cleaned them out every so often.

 

[CHEMCHEF]

I just saw this post, and I was going to suggest cleaning the teeth of your overflow out. I had this problem on my old cichlid tank, using one of those aqua clear surface skimmer atachment doo dads

well I took the box out and cleaned it very well and then put it back. Believe it or not, its running much better now and the oily film was gone within an hour. So I guess small amounts of algae in the teeth of the overflow can cut the water flow down.

Good to know.

 

[pecan2phat]

Also surface agitation from either the return line or powerheads will help. The flow needs to break the surface.

 

[MikeyZO]

Justin - yeah, I have the clear tubes and I clean them out every time.

James - too little too late. Oh and I still have to get that food from you LOL

Pecan - Thanks, I actually moved one to do just that.

 

[lazibonez]

Mike, its a matter of how your water flow movement is. Try to play around with your powerhead aim it so it push water to the overflow box.