Film / sheen on the water

[Bobby McGovern]

This morning the sun was shining just so on my fish tank and sump and I noticed a very light film on the water.  If I touch it and rub my fingers together you can feel the very slightest oiliness I guess you could say.  

I just started fishless cycling two weeks ago....

pH 7.4

Temp - 71 - 76

One quart of Maxicrop

Ammonia 4ppm

Nitrite 0

Nitrate 0

It's definitely not a heavy oil so I'm pretty sure it's not from my pump. It's barely detectable.  I only noticed it because of the way the sun was shining on it.

Could it be from the Maxicrop?  There's a small amount of naturally occurring oil in most vegetable matter.

I just want to make sure it's nothing I should be worrying about...

Thanks...

[William Gennaro]

I dont know if this is the correct answer. But I had a similar issue ( an oily or slick sheen on top of the water ) and this is what I did. Well I have a 55gal drum for my fish tank (tank is horizontal) so I removed one of the screw caps at the top of the drum and put a old sock rubber banded over the hole. And once a day I add some extra water so the tank will slightly over flow and run out of this hole. Seems to work great, no more slick.

[TCLynx]

sometimes plastics or other components might have a residue on them which could cause the film.  I've even seen a slight film just from the oils in the fish feed.

If you have never used any fish feed in the system yet and there are no fish.  I might recommend simply using a towel or paper towel to try to do a quick swipe over the surface of the water to remove the film kinda the way you might when skimming the oils off of chicken stock or broth.

[Vlad Jovanovic]

Bobby, when you take a stick and gently poke through the film and then withdraw the stick...does the film break apart there, or does it converge and swirl back together? 

[Jim Fisk]

I noticed tiny oil "spots" in my system early on (during Comet and cycling period) and I immediately ordered an oiless mag drive pond pump. First thing Bobby is to make sure your pump is oiless. If there is a fill port on top it is oil filled. Beyond that algae, bacteria, feed, organic break down going anaerobic: so many things. Electric motor oil btw is very light weight and some will bypass the seal always. No such thing as a perfect seal so be sure u are oiless. In a closed system a small seepage can really add up.

Also if your ibc contained synthetic oil it can be still seeping out of the plastic. The list of pos is almost endless so start with the big things and work your way down the list. I way over did the old pond fish food when I was getting the sys started and I believe it went anaerobic in my first 35gal biofilter. That was the first thing I removed and then the oil filled pump. Haven't seen any oil spots since. (and saved a boat load of electricity usage by replacing that utility pump)

BTW I hope u got my last message as I don't see it at my end at all. I have lost a lot of type time on this forum due to time limits. Let me know if I still owe you a response.

[Vlad Jovanovic]

Bobby, save yourself some potential headaches and cash by doing the 'stick test' before you go and start changing out any equipment...What Jim says is true, but there are a number of harmless and totally natural causes for seeing such an opalescent film on your water as well...From certain bacterial action, to certain plant essential elements being released into the water stream...All harmless and no cause for alarm.

Turn off your pumps, let the water go still and poke the film with a stick and carefully observe whether it breaks up, or swirls and converges back together. How the film behaves when you do this little test will determine whether the film is indeed from your pump or IBC, or not.

Lertisan is pretty slick stuff. Hopefully you cleaned out those IBC's real well.

[Bobby McGovern]

Vlad,

It swirls and converges back together.

We pressure washed the sh** out of the IBCs and then scrubbed again with the Oxyclean so I doubt there's any Lertisan left.  The feeling I get when I rub my fingers together is not the slick "lube" feeling of Lertisan.  It's sort of what it feels like when you've just eaten a potato chip and rubbed your fingers together.  Not super oily, just something there.

The seaweed stuff has left a really dark ring around the inside of the IBCs and on any plumbing.  It has that same feel.

Tomorrow I'll wipe down everything with paper towels and see what happens....

Thanks everyone...

Vlad Jovanovic said:

Bobby, when you take a stick and gently poke through the film and then withdraw the stick...does the film break apart there, or does it converge and swirl back together? 

[Bobby McGovern]

I'll take the pump out tomorrow and see if it has a fill port.  It's an 1800 gph Superior sump pump.  

Jim Fisk said:

I noticed tiny oil "spots" in my system early on (during Comet and cycling period) and I immediately ordered an oiless mag drive pond pump. First thing Bobby is to make sure your pump is oiless. If there is a fill port on top it is oil filled. Beyond that algae, bacteria, feed, organic break down going anaerobic: so many things. Electric motor oil btw is very light weight and some will bypass the seal always. No such thing as a perfect seal so be sure u are oiless. In a closed system a small seepage can really add up.

Also if your ibc contained synthetic oil it can be still seeping out of the plastic. The list of pos is almost endless so start with the big things and work your way down the list. I way over did the old pond fish food when I was getting the sys started and I believe it went anaerobic in my first 35gal biofilter. That was the first thing I removed and then the oil filled pump. Haven't seen any oil spots since. (and saved a boat load of electricity usage by replacing that utility pump)

BTW I hope u got my last message as I don't see it at my end at all. I have lost a lot of type time on this forum due to time limits. Let me know if I still owe you a response.

[Vlad Jovanovic]

Damn... swirls backs together eh? Then it's probably not one of those natural causes...

Bobby McGovern said:

Vlad,

It swirls and converges back together.

We pressure washed the sh** out of the IBCs and then scrubbed again with the Oxyclean so I doubt there's any Lertisan left.  The feeling I get when I rub my fingers together is not the slick "lube" feeling of Lertisan.  It's sort of what it feels like when you've just eaten a potato chip and rubbed your fingers together.  Not super oily, just something there.

The seaweed stuff has left a really dark ring around the inside of the IBCs and on any plumbing.  It has that same feel.

Tomorrow I'll wipe down everything with paper towels and see what happens....

Thanks everyone...

Vlad Jovanovic said:

Bobby, when you take a stick and gently poke through the film and then withdraw the stick...does the film break apart there, or does it converge and swirl back together? 

[Bobby McGovern]

This is strange but when I use a stick it immediately comes back together.  However if I use the glass test tube while testing the water it stays apart for a while...

The sheen is so light I had to move around to  find it.  The light had to be just so.

Vlad Jovanovic said:

Damn... swirls backs together eh? Then it's probably not one of those natural causes...

Bobby McGovern said:

Vlad,

It swirls and converges back together.

We pressure washed the sh** out of the IBCs and then scrubbed again with the Oxyclean so I doubt there's any Lertisan left.  The feeling I get when I rub my fingers together is not the slick "lube" feeling of Lertisan.  It's sort of what it feels like when you've just eaten a potato chip and rubbed your fingers together.  Not super oily, just something there.

The seaweed stuff has left a really dark ring around the inside of the IBCs and on any plumbing.  It has that same feel.

Tomorrow I'll wipe down everything with paper towels and see what happens....

Thanks everyone...

Vlad Jovanovic said:

Bobby, when you take a stick and gently poke through the film and then withdraw the stick...does the film break apart there, or does it converge and swirl back together? 

[Bobby McGovern]

Today there is no sheen at all.  I think maybe it had something to do with the liquid seaweed breaking down or whatever it does.  I just have the nasty ring.

[Vlad Jovanovic]

Hi Bobby, sorry I missed your post from yesterday. Yeah it can be tough to see, the light has to be 'right' in relation to your viewing angle and all...Strange that the film should break up with glass, but not with a stick, or nail or whatever...Your basically trying to lightly disturb the film and see if it 'cracks up' or not...

I might be wrong, but part of me wants to chalk it up to maybe you 'missing it' the first time around. It's a very small detail to observe, that's for sure, but a very tell-tale one. Hopefully that will be the end of it. You could wait a couple days and check out what's happening, if there is still no sheen... add some MaxiCrop and then pay attention and look for it again...

Maybe someone who uses that specific product could tell you more about the discoloration and rings part...

[TCLynx]

By the color of the ring, I might say perhaps you didn't shake the bottle up really well each time you used some and you perhaps went a little overboard on the dose?  Not much to worry about though, I've never heard of seasol or maxicrop hurting fish.  I usually try to dribble it into the grow beds were the water enters instead of pouring it into the tank.