Diatoms or what?

[Joshua Douch]

Hey im new here.
I have some shellies (multies) and basically my problems go like this:

(Basically I had cyanobacteria and then that went now I have a weird brown 'algae' that won't go away)

1) Cyanobacteria appeared
2) I asked advice on another forum, and proceeded with a 7 day black out
3) Cyanobacteria appeared to be gone
4) It reappears, still green, but along with another brown looking 'algae'
5) I bought a bottled product as I could not get erythromycin.
6) I moved tank out of sunlight and I do the bottled product treatment as advised.
7) There is no longer a green 'algae' and the algae on the glass does not come off in a film/slime anymore.
8 ) Brown 'algae' seems to stick to the glass like small brown dots(in some places it turns the glass brown) and turns the substrate brown ALTHOUGH the algae isn't visually physically growing on the substrate.

It is a 20G with 2 fish and 15 fry
Nitrates currently in between 40 and 80 as I have high nitrates in my tap water... I am contacting my water company to see if they can do anything about it
Nitrites 0

I have since altered my light time to 6 hours
I have added live plants

Is this really diatoms or just cyanobacteria undercover?
Any other advice? Its a pain!

 

[Byron]

Cyanobacteria is caused by organics in the presence of light. Blackouts temporarily deal with it, but if the organics aspect is not rectified, and if light is again introduced, it will likely return. Erythromycin or similar antibiotics are sometimes suggested, but this is very dangerous; you should absolutely never use antibiotics in an aquarium except when it is essential to deal with a specific fish bacterial disease. Think of it being similar to humans taking antibiotics unnecessarily or for too long, they stop working. Dealing with organics and light is the method.

Nitrates are often indicative of organics, so your source water is an issue. But keeping natural nitrate within the aquarium as low as possible, and controlling the light, should help. Sunlight striking an aquarium is always a problem, so fixing that was good.

As for the brown, this is a type of algae. If it comes off surfaces readily and easily with your fingertips, it is diatoms. If it does not easily come off without scraping, it is probably a form of brush algae. Again, light and nutrients/organics cause algae. Live plants should help as they will use much of the light and nutrients. Reducing the intensity of the light may be helpful, depending what it is; duration is a factor, but if the light is too intense for the balance, duration will not have much effect. Both are part of the balance.

Byron.

 

[Joshua Douch]

Thanks for the info. It is annoying to find that many different websites have different information e.g. that diatoms is caused by light and that it isn't, glad to finally have an answer.
I bought the cheapest LED light that I possibly could when I set up this aquarium which is why I think it is the main issue. Would you advise that I get a different light? If so what type? LED or fluorescent? Are there lights that can sit on top of a lid? I currently am using a transparent polycarbonate lid with the LED light stuck underneath in the water, probably not the best idea even if it does claim it is waterproof!

Another reason I believe the light is an issue is because I have another tank with random fish in it that has a proper light that came with the tank, this has been using the same quality water but has never had extreme algae issues like this.

 

[Byron]

Thanks for the info. It is annoying to find that many different websites have different information e.g. that diatoms is caused by light and that it isn't, glad to finally have an answer.
I bought the cheapest LED light that I possibly could when I set up this aquarium which is why I think it is the main issue. Would you advise that I get a different light? If so what type? LED or fluorescent? Are there lights that can sit on top of a lid? I currently am using a transparent polycarbonate lid with the LED light stuck underneath in the water, probably not the best idea even if it does claim it is waterproof!

Another reason I believe the light is an issue is because I have another tank with random fish in it that has a proper light that came with the tank, this has been using the same quality water but has never had extreme algae issues like this.

My forays into LED lighting have all been failures, so I stick with T8 fluorescent because I understand it and have things balanced. If you have live plants, then lighting is the most important factor. Without adequate light for the plant species, meaning intensity, it cannot photosynthesize. Different plants have differing light requirements, so not everything will grow under every light. Without live plants, the lighting is more whatever appeals to you, though lighting does affect fish more than many realize.

There are many LED lighting fixtures, some good with plants but many not, and the intensity is often one reason. But there is also the spectrum; much LED is on the blue side of white, lacking sufficient red which is the most important colour for photosynthesis. If things are fine in your other tank, then replacing the lighting in this one may be advisable. LED fixtures and fluorescent will usually sit across the tank frame, so you can have a cover glass between the light and the water. A cover glass unit plus a lighting fixture is sometimes less expensive than a combo hood.

 

[Joshua Douch]

Thanks. How does "T5 Aquarium 24" Fish Tank Overhead Lighting Two Tube System 60cm" sound? Again, it is the cheapest I can find (40GBP) it comes with 1 x 10000k and 1x Actinic. What exactly is the difference between these two?

So would you think that the light overall could be causing the diatoms to not go away? If it isn't going to make much difference I may hold off of it for a bit.

Thanks.

 

[Byron]

Thanks. How does "T5 Aquarium 24" Fish Tank Overhead Lighting Two Tube System 60cm" sound? Again, it is the cheapest I can find (40GBP) it comes with 1 x 10000k and 1x Actinic. What exactly is the difference between these two?

So would you think that the light overall could be causing the diatoms to not go away? If it isn't going to make much difference I may hold off of it for a bit.

Thanks.

Two big problems with that lighting unit. First, it is T5, and this is brighter light than T8 in the same length and type of tube. For example, a T5 24-inch Life-Glo emits approximately 1.5 times as much light intensity as the same tube in T8. Over a 20g, one T8 24-inch tube would be adequate; two would inevitably be too much (I have this over my 3-foot 40g and 33g tanks). Two T5 would be even worse.

The other issue is the type of tubes. Actinic is very blue light, suited to marine tanks with corals, but not freshwater plant tanks. The 10,000K is also very blue. The "K" is Kelvin, the colour temperature of light expressed as degrees Kelvin. The lower the K number, the "warmer" the light, meaning more red and less blue; the higher the K, the more blue and less red. Midday sun is somewhere in the 6000K range. I have experimented with T8 tubes over the last 8 years, and find the best light for plants and true colour rendition are those in the 5000K to 7000K range. If I have just one tube over the tank, it will always be a 6500K Daylight. If I have two tubes, I like to mix a 6500K and a 5000K which warms it a tad. Remember what I said about red driving photosynthesis...the lack of almost all red in the Actinic and 10,000K light would not be beneficial for plants. It would also give a very cold white, and the "warm" colours on the fish like reds and yellows would be almost non-existent.

T8 fixtures are getting very hard to find these days, because first T5 and then LED have become so popular. T5 works over marine tanks when you need more intense light for corals, and in fact that is what drove the industry to move to T5 from T8; you can increase the intensity with fewer tubes. LED I know little about as I mentioned previously, but there are some good units available, though usually quite expensive. I have tried I think 5 different units, and all went back to the store. I couldn't even begin to match my T8 lighting in either intensity or spectrum.

 

[Joshua Douch]

Thanks! I did try searching what type of colour they were and did read that T5 was more powerful.

I shall keep searching. Thanks again!

 

[Joshua Douch]

I don't seem to be coming across any T8 overhead hood options...
If you were to say LED, what would I specifically be looking for in order for it to be sufficient?

 

[Byron]

I don't seem to be coming across any T8 overhead hood options...
If you were to say LED, what would I specifically be looking for in order for it to be sufficient?

My old T8 fixtures have been giving out over the past couple of years, they are old (bought in 1995, 1996, 1998) and not having any luck finding new ones I have taken to buying shop lights at Home Depot and using the housing for these. So I know how scarce T8 is these days, in aquarium lighting.

There are some other members who have found good LED light for planted tanks, I will leave it to them to offer suggestions. My five attempts failed, and now that I have replaced/repaired all my T8 fixtures, I'm good for what years I have left--unless they stop making T8 tubes of course.