# Green Slime



## hotsauce1183 (Jun 26, 2016)

For some months now I have been struggling with a fast growing green slime in my 30 gallon freshwater tank. I have gone to several local fish stores but I get as many answers and suggested solutions as there are stores. One store says its cyano-bacteria and the next says its algae whicle the third says its something else. I am really hoping the experts on this forum can help.

I have stored some pictures of the problem areas at: 
https://drive.google.com/folderview?id=0B130iRB0lTRrOWlsQnNTR21TaW8
In the photos, the silver dots on the rear glass of the aquarium are bubbles being generated by this slime. Oxygen bubbles?

This slime is easy to vacuum off, i.e. its hold on plants, gravel, and aquarium sidewalls is not very strong. But I can vacuum the whole tank clean and in a few weeks its is back heavier than ever. My chemistry is mostly normal with nitrates usually running in the 40-50 range and nitrites are 0-.5 at most. I have tired Dr. Tim's Re-Fresh treatments without any noticeable affects. This tank is filtered with a large Eheim external canister filter and I keep the temp around 76 F. I have done drastic water changes using both tap water and RO from the local water store. When I use RO I always supplement with Dr. Tim's bacteria and mineral liquid. My lighting consists of both a new Aqueon Floramax 17 watt T8 and a new T2 13 watt.


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## DJRansome (Oct 29, 2005)

Cyanobacteria. Let your nitrates climb up to minimum of 10ppm. What is your GPH? Some find increased flow helps. For me I get it when the fast-growing plants eat all the nitrates and then start to die off for lack of fertilizer. They leak liquid that the cyanobacteria likes. Solution? Fertilize. Or switch to slow growing plants.

You can get rid of it by dosing Erthyromycin as directed for a week. But that can harm your beneficial bacteria and if you don't remove the root cause it will come back.

Why are you using RO water? You may want to stop adding bacteria...when in doubt eliminate chemicals.


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## hotsauce1183 (Jun 26, 2016)

Thanks you DJransome for the quick and efficient reply. I do not eactly know the GPM of the Eheim. It is the second largest of the line which I always thought should be overkill for a 30 gallon tank.

I took your advice and deposited a Flourish Tab at the base of each major plant in the tank. Time will tell if this helps but I am optimistic with your advice.

As for RO, that is what my local water store supplies. They only have an RO plant and they reintroduce a "mineral package" for flavor and balance. As for the Dr. Tim's bacterial additives I would be inclined to agree. I cant really say I have ever observed any direct [positive] result from using them. Logically speaking, they shouldnt be necessary in a healthy tank. On the other hand my tank is arguably not healthy or it wouldnt be suffering from such a profound CyanoB problem.

Tanks again for the advice. I will report later on the results of increasing the plant fertilizer.


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## DJRansome (Oct 29, 2005)

You can Google GPH and the model of your tank to get the specs.

The tabs will help the root feeders...do you have plants that gather nutrients from the water? Letting nitrate creep up or adding it will help.


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## hotsauce1183 (Jun 26, 2016)

Well, its been a week and the addition of the fertilizer tabs still hasnt resulted in any improvement. The CyanoB is still running rampant. The external canister filter is an Eheim 2234. It is suppossed to manage tanks up to 60 Gallons (mine is 30) and has a 145 GPH pump. I havent taken this one apart for any type of cleaning in at least 3 months and I usually only open it up and rinse the media about twice a year. Even then I only rinse the media in water taken from the aquarium. This is mostly because our local water has a lot of chlorine in it so I avoid using tap water.

I also have a smaller 75GPH circulation pump inside the tank.


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## DJRansome (Oct 29, 2005)

Try removing the plants. What is your nitrate?


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## hotsauce1183 (Jun 26, 2016)

Thanks DJRansome
Chemistry, using API test strips AND liquid chem test kits, is:
GH = 30-60
KH = 0-40
PH = 6.0-6.5
NO2= 0-.5
NO3=80-160
The test strips and the wet chem test kits both agree with each other. That has not always been the case for me in the past. Probably due to the age of the strips and kits. An NO3 reading of around 100 is a recent thing. Obviously I need to get that down but first I need to understand why it is so high. This tank is currently underpopulated and gets very lightly fed twice a day with very little or no food flakes getting to the bottom of the tank.


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## Aaron S (Apr 4, 2015)

How often do you vacuum the gravel and how do you vacuum the gravel?


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## hotsauce1183 (Jun 26, 2016)

Aaron S said:


> How often do you vacuum the gravel and how do you vacuum the gravel?


I built a water polishing system from a pond pump and a large household canister filter back when I had several larger tanks. I use that at least once a month but with my 30 gallon the polishing system isn't as effective because it is so heavily planted.


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## Aaron S (Apr 4, 2015)

The reason I ask is because you may have poo stuck deep in the gravel which is decaying. I would try to get a really deep clean going for it when you do your water changes to get the nitrates down.


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## hotsauce1183 (Jun 26, 2016)

Thanks - yah, i am thinking of just removing all of the years old plants, doing a really deep cleaning, and then getting all new plants.

One additional question I would have for the experts is how often do you recommend replacing the filter media in the eheim?


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## DJRansome (Oct 29, 2005)

I replace the fine filter pad with every cleaning and the rest of the media...never so far in 10 years. I understand the sponges will eventually deteriorate so maybe every 10 years for those. The sintered glass...looks fine to me.


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## Aaron S (Apr 4, 2015)

What media do you have in it? When I was running a canister filter, I had 300micron media down half the filter followed by 1/6th of the space with gradations of filter media from 300 to 100micron then a compartment with bio media in pantyhose so it wouldn't get scuzzy if anything passed by all my filter floss, then a carbon bed (which I do not use in my HOB's anymore). You never change the bio media. I would clean and/or replace the filter floss monthly. The monthly cleaning included dumping all the water out of the canister itself and cleaning out any solids in the bottom.

If you think your nitrates are raising faster than it should then you have poo/food stuck somewhere and decomposing. In the filter or in the gravel are really the only two places this can occur.


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## hotsauce1183 (Jun 26, 2016)

The one thing that doesn't make sense to me is why the plants aren't using up the fish poo stuck in the gravel as fertilizer. Isn't that the way it is supposed to work?


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## DJRansome (Oct 29, 2005)

They will not use all. Also maybe they are not healthy enough. Finally, some plants feed through the leaves more than others and some are slow growers (when I added fertilizer...I had fast growing plants...valisneria. And I added nitrate to the water.).


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## hotsauce1183 (Jun 26, 2016)

I have been avoiding liquid fertilizer as I wasn't sure how it would affect the canister or even if the canister wouldn't just filter it out of the water.


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## DJRansome (Oct 29, 2005)

I added the pure and separate chemicals...nitrate and phosphate, so I could get the ratio I wanted. It's nitrate just like the fish make though. So maybe your plants are slow growers (my nitrate went to zero, then the cyanobacteria started).

I like your idea of removing plants and substrate and freshening up the tank.


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## elenor (Jan 17, 2017)

Cyanobacteria is often referred as the blue/green algae. Its prior cause of occurrence in freshwater lakes is improper lighting, the presence of nutrients and lack of O2 environment. Cyanobacteria could be completely removed by a series of processes such as changing the lighting, removing the algae with gravel cleaner, aerate the tank so that it is availed with plenty of O2. Also take care to maintain an environment that won't allow the reappearance of the bacteria.


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