# 2 ?'s, surface film and pH



## Valley (Feb 28, 2007)

My tank is just under a year old now. It is settling and everything is wonderful.... except one little thing. I can not keep the film off the surface of the water without running an HOB filter every other day. I feed mostly frozen food but no matter how I rinse it my effort seems to make little difference, and feeding flake buys me less than a day. There has been nothing sprayed in the air in there for months, the room is hardly used and the tank is not near a vent. It is open top however. It is too lightly stocked (working on that) with 1" MG organic choice and .75" black gravel/onyx sand. 

So does any one have any idea what is causing it? Is there a reasonable way to remove it or stop it without causing surface agitation? 

Question 2 is more curiosity. My pH in that tank is 7.4, GH 5, KH 4. Is there a way to increase the KH without increasing the pH? I have been surprised that my pH didn't decrease as the tank matured but it is exactly the same as the day I filled it. Which, I suppose is pretty good.


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## Red_Rose (Mar 18, 2007)

Hello,

The film you are describing is a bio film which is harmless. The only live food my fish get is what grows in their tanks yet there I get this film from time to time. Other then water movement, I don't know of any other way to get rid of it since I always leave the filters in the tanks running for circulation.

Now as for your pH, I don't think there is a way to raise your KH without the ph being affected. Your KH is fine but if I were you, I'd want to raise my GH because a GH of 5 seems a bit low. In Diana's book, a GH of 8 or higher is what's normally recommended for NPT's. Raising your GH would probably increase your KH as well but your pH will go up with the two.


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## Valley (Feb 28, 2007)

Thanks Red Rose. That film has been driving me nuts! It's good to know it's not a risk, but it's still gross looking. So I guess I'll stick with the filter until I find a better way. 

I'm working on the GH. I added quite a bit of cuttle bone in the soil when I started and didn't want to mess with the GH too much until I saw the effect of that. I've decided it did very little, so I've added a good deal of crushed cuttle bone. I know there are faster ways but I've used this method to add calcium and magnesium for snails for several years and I know it doesn't mess with my pH. If that doesn't give me the results I want I'll go a little with something new. 

If my pH starts to rise I'll have to adjust it down  It's on the upper limit of a few of my fish as it is. So, peat is the most stable method right? Anyone have a good source for the stuff? Can I just use what they sell for orchids?? lol I have some live peat moss, it's a shame I can't just plant it in there.


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## Red_Rose (Mar 18, 2007)

I've tried to lower the pH in a tank before and needless to say, I've since decided that just leaving it be is the best thing to do but then again, the fish that I have are quite hardy and don't mind a more alkaline pH. Of course, with our tap water, it's pretty much pointless to try to soften it because it's almost like liquid rock! lol

Since your KH is lower, you could try using peat to lower the pH if needed but I'd be worried about pH fluctuations which can make fish sick.

Do you mind me asking what type of fish you have that don't like a higher pH?


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## Valley (Feb 28, 2007)

I don't mind you asking at all... But I'll have to get back to you. It was one of those things where I saw the info, made a mental note about it, but forgot which fish it was about. I've got, and prefer mostly South American fish. Tetras mostly and am drooling over some Apistos. They're mostly soft water fish so I only want to raise the GH/KH enough to make the plants happy but not enough to make the fish sad. But like I said, I can't recall exactly which fish I was pushing pH limits on. I'll get back to you.


Sorry, I know that was a ramble, but I'm at work and it's been a crazy crazy day.


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## bartoli (May 8, 2006)

Valley said:


> That film has been driving me nuts! It's good to know it's not a risk, but it's still gross looking. So I guess I'll stick with the filter until I find a better way.


My way of dealing with surface film is to attach an Eheim surface suction extractor to a Marineland maxi-jet submersible utility pump 400. The pump is controlled by a timer. It turns on twice a day for 30 minutes at a time. That works pretty well - as long as I do not let the water level drops too much due to evaporation.

Note that even though the Tom Aquatics Aquarium Surface Skimmer is much less expensive than Eheim, it does not work with a timer. When the pump was off, the surface skimmer's 360-degree intake float dropped its level as well. However, when the pump was back on again, the intake float failed to rise to the required level unless I manually played with the flow control valve again.


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## Diana K (Dec 20, 2007)

Your GH and KH are fine for plants. If they want to use up the calcium or magnesium you will see the GH dropping, then you could add something to fix the problem. 
If the plants start using the KH as a source of carbon, then you will see it, and, likely, the pH drop. Then you could do something about it. As long as the readings are stable then the plants are taking what they need, and the fish food is replacing the Ca and Mg. 

Keep the filter going to keep the surface scum away. The gentle motion of the surface is good to encourage gas exchange and the water movement in the tank circulates the things the plants need.


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## Valley (Feb 28, 2007)

bartoli, thank you, I'll look into those. Do they cause much surface movement? What happens if the water drops too low? I'm bad about putting off things that aren't imperative. 

 Thanks Diana. The snails were actually complaining (shells looking rough) about a lack of calcium, and I was aiming for gh7 to start with... So I added more than I thought the snails would use right away. If I'm fine where I am, I suppose I'll just take care of the snails from now on. That is easy enough. My concern with the filter is loss of co2. If I'm getting rid of too much co2 how will I know? I don't know that I trust the test I have. The current filter is way undersized for this tank but still makes a lot of "splash" even when the output is under the water. I might try an even smaller one. Maybe a 10g filter instead of a 30g. It's not like I need actual filtration...


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## bartoli (May 8, 2006)

Valley said:


> Do they cause much surface movement?


I guess your concern is about CO2 lost. Bear in mind that a surface skimmer has to generate a lot of bursting bubbles in order to remove surface film. In the process, some CO2 will be lost. I don't know how to quantify the CO2 lost. But I placed the surface skimmer on a timer to keep the CO2 lost to the minimum.



Valley said:


> What happens if the water drops too low?


When the water level drops too low, the skimmer ends up sucking in the water right below the surface film and not the film itself. Thus, the surface film remains.


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## dwalstad (Apr 14, 2006)

Diana K said:


> Your GH and KH are fine for plants. If they want to use up the calcium or magnesium you will see the GH dropping, then you could add something to fix the problem.
> If the plants start using the KH as a source of carbon, then you will see it, and, likely, the pH drop. Then you could do something about it. As long as the readings are stable then the plants are taking what they need, and the fish food is replacing the Ca and Mg.
> QUOTE]
> 
> ...


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