My Planted Tank is Going Down the Tubes. Help!

My plant/fish/equipment specs and pictures are included at the bottom of this post for your reference.

I have a fish tank that was fishless cycled correctly and have had plants and fish in it for the last 6 weeks. This is my first planted tank. I have tried to go "low tech" with the appropriate plants. Water Parameters for the last 4 weeks have been pretty consistent at pH 7.5-7.6, Ammonia 0-0.3, Nitrite 0, Nitrate 0, with a 5 gallon water change once per week. I am running my Finnex 24/7 light in the 24 hour day cycle simulation mode.

The fish all seem super healthy. I have two problems: the plant growth appears to have slowed quite a bit and algae has started taking over.

The plants all seemed fine within the first approximately two weeks. The Bacopa and Pennywort were both growing pretty fast and needed trimmings once a week and the wisteria quickly lost most of its leaves and grew them back (apparently normal as it adapts to the new water conditions). The Bacopa and Wisteria have pretty much stopped growing completely; the pennywort still grows, just slower and it has some poor looking leaves that get trimmed.

I have been dosing fertilizers at the following rate:

Flourish Comprehensive 1.5 mL once a week (bottle recommends 2.5 mL weekly)
Flourish Excel 1.5 mL every 3 days (bottle recommends 5 mL twice weekly)
Flourish Potassium 1 mL once a week (bottle recommends 2.9 mL every other day) (because the pennywort was getting multiple leaves with a lot of little dots)

As shown in the following pictures, within the last 3 or so weeks the algae has really taken off. The biggest problem is this short hairlike algae creating a fuzzy look that covers a lot of my plant leaves and stems, driftwood, and the background. It is by far thickest within the top 5-6 inches of the tank. I also have this really long single strand type of algae that grows up to like 5+ inches long before I manually pull it out. Those single strands are also relatively strong.

I have a couple theories that may be causing or contributing to the problem, but I would defer to more experienced input.

1. Nitrates are 0 so I am worried my plants are missing nitrogen.
2. Since algae is much worse at the top 6-inches, there might be too strong of light.
3. Fish stocking is too low for the tank.
4. My water filter is not quite powerful enough. The box says it is good for 20-50 gallons and I have a 29 gallon tank. There doesn't seem to be very much of a current on the left side of the tank (the java moss barely moves on that side).

How do you recommend I get my plants growing and the algae reduced?

Thanks









Plants
Java Moss
Brazilian Pennywort
Bacopa caroliniana
Java Fern
Water Wisteria
Anubias Nana

Fish
6 X-ray Tetra
7 Neon Tetra
3 Peppered Cory
1 Amano Shrimp

29 Gallon Rectangular Tank (18-inches high)
Finnex 24/7 Light
Gravel Substrate (finer grain than average gravel) @ 2-3.5-inches deep
Aquaclear 50 (HOB) Filter (no carbon)
pH 7.6
Hard Water (I don't know the numbers, but it is hard for sure)

 

HI and welcome to Fishlore.

"I have a fish tank that was fishless cycled correctly and have had plants and fish in it for the last 6 weeks. This is my first planted tank. I have tried to go "low tech" with the appropriate plants. Water Parameters for the last 4 weeks have been pretty consistent at pH 7.5-7.6, ammonia 0-0.3, 0, 0, with a 5 gallon water change once per week. I am running my Finnex 24/7 light in the 24 hour day cycle simulation mode."

According to your own water parameters, your tank is NOT cycled. You should have 0ppm Ammonia, 0ppm Nitrite and between 1-20ppm Nitrate. Either it never finished cycling or it crashed after you believed it was cycled.

Please read up on the nitrogen cycle and fishless tank cycling.

I won't even touch on the rest at this time, I'll leave that to someone else.

 

Were you at one point getting a nitrate reading, and were you testing during the cycle to make sure you had ammonia spike, which fell as nitrites spiked, which fell as nitrates spiked? I only ask becase the previous answer suggests you didn't cycle the tank properly and that may not be the case. In tanks planted heavily enough, and once the plans "establish" themselves they begin to feed on the nitrogen from the nitrate ion and it is very possible to see very little to no nitrates in a heavily planted tank. Java moss is a known "nitrate sponge," I might add. With a small enough stocking there may be just enough nitrates being produced to provide a nitrogen source for the plants, but does not leave enough to build up a testable amount. Also, make sure you're using a liquid kit and you read the directions for the nitrate test specifically. It's not like the ammonia tests where one adds the drops of both containers and mix, there's more to it than that and if not done correctly, one will not get a proper and true reading and in most cases will always seem like it reads 0-5ppm. I learned this the hard way. There is not enough information to know whether the tank is cycled or if you have enough plants to cover the minimal bioload, that's my reason for covering both bases.

As far dosing with fertilizers goes, especially with excel and flourish, dose them how the bottle says to. From what you've stated, you're cutting the recommended dose and I would not recommend that. I was having issues with hair algae showing up as well as brown algae in my heavily planted 13 gallon. (although my nerites were doing a good job of keeping the brown spot algae at bay) I now dose the following: 1mL potassium, 1mL phosphorus every Sunday. I dose 2mL Excel daily, and 1mL Iron every other day. (Note that the bottle says to dose daily or every other day, not twice a week as you've suggested.) I originally dosed excel at 1mL and the others were 1-2mL two to three times a week. A few weeks into that is when I noticed the algae showing up, and noticed I was by technicality under-dosing excel by .3mL. I increased to 2mL excel daily, and everything but Iron once a week at a smaller dose. There is almost zero algae in the tank a few weeks later, and my plant growth has exploded. I listed my regiment as anecdotal evidence to support why a proper regiment is paramount in keeping algae at bay and plants happy. Some will suggest not to overdose whatsoever on excel as if one extra drop is going to kill all the livestock. If one slightly overdoses on excel it begins to act as an algecide and dose wonders at warding off excess algae. Notice, however, that I did not quite double up on excel, as I would technically need 2.6mL daily to do so. One can kill livestock by overdosing on excel because it begins to rob the tank of oxygen, that's also why one should dose immediately when the lights come on or just a little before. Take care not to overdose too much. It allows the plants to use it most effectively and while they're photosynthesizing, they in turn produce oxygen that is added to the water column. Flourish I would recommend you dose the normal amount that the bottle suggests, and start at just once a week. Too many nutrients will absolutely cause algae problem, and at least from my experience, its easier to dose it minimally and if need be you can increase to twice a week later on down the road. I should also note that one normally will not see an immediate response with plants, they take time to show changes, especially slow growing plants such as various types of anubias.

The 24/7 is a great light but I've read time and time again from people who use the 24/7 setting having issues with too much light and therefore getting algae problems. If possible, put the light on a timer. Run it for 6-8 hours a day only, so I advise you have it come on when you are at home the most, so you can still see into the tank and enjoy your hard work. I personally don't have that fixture so I'm not sure if it comes with its own timer like some other LED bars do. If not, a wall plug-in timer isn't too expensive.

In short, it sounds like you are blasting the tank with too much light and utilizing an improper dosing regiment. Balancing light with nutrients is key to keeping algae at bay while keeping the plants lush and happy. I know my response was lengthy, but hopefully I've covered everything.

 

My understanding would be immediately that you are providing too much light and not enough fertilizer for the tank. Under similar situations I've seen suggested an immediate reduction in light perhaps @6 hours or a siesta style of 4 on 4 off 4 on then off for the night. With easier plants like you have I'd go ahead and up the comprehensive and the excel atleast to normal doses.
As reference I do 9ml comprehensive a week and liquid co2 daily before lights come on. Currently in my 36 bowfront with wisteria, swords, hairgrass, and pogostemon helferi. Just this last week I'm only starting to see green spot algae on the glass but only up top closest to the light.

 

I would suggest a black out for at least 3 days to kill the algae and to start all over again. I personally use the Seachem fertilizer line and use all of the products. I also follow their dosage chart with the exception that I dose according to my tank, but I never go over the recommended dose, the EI method.
'I believe the reason you have the hair algae in only certain places is because your light is not penetrating the lower part of the tank. The algae will take advantage of the extra nutrients and where the light is best for it to grow.
I am not familiar with the finnex 24 hour cycle but I think you are leaving your lights on way too long, 7-8 hours is sufficient even in a non CO2 tank(low tech).
I had a big algae problem at one time and it was due to over fertilizing and too much light. I took a couple of thick towels and covere the entire tank for 3 days and did not dose any fertilizer's or feed my fish in the tank. After the 3rd day you will see a big difference in the algae population. If you still have an algae problem after 3 days it may take another 1-3 days. It all depends on your tank.
once you get rid of your algae problem I would read up on the EI dosage method. Your tank will tell you what it needs and what it doesn't. It's just a matter of time. I am still trying to perfect my tank.

Good Luck!

 

I got to the part in your post where you mentioned running the 24/7 mode (promise to finish reading) but I'm like %80 sure that's a huge part of your issue, if not the only issue.

I have the same light, and here's my experience. Every color variation of the 24/7 mode has a PAR value. So during the night when the moonlight are on you're lights still trying to grow plants. In fact, it's trying to grow plants every moment a light is on just at varying low levels of intensity all night and all day... Well that's an issue because plants need rest because they can't readily photosynthesis all day, and even at night under very low PAR. Algae quickly jumps on the low levels of light the plants aren't using and now you have an algae farm. This has happened every time I've used the 24/7 mode.

My suggestion is to get an actual timer, set it for 6-8 hours, and turn RGB all the way to 10 clicks up, then turn your white light value down to 7. Keep turning your white light (highest PAR value) down every couple of weeks if algae isn't disappearing.

If I'm right a month from now you'll have a drastic improvement and all it will cost is $6 for a timer and some time.

You just have to forget all about the 24:7 setting even though it's beautiful. It's the worst aspect of this light, while the best is by far the ability to tune the intensity of the light, making it incredibly easy to correct most algae issues once you're familiar with it.

 

HI and welcome to Fishlore.

"I have a fish tank that was fishless cycled correctly and have had plants and fish in it for the last 6 weeks. This is my first planted tank. I have tried to go "low tech" with the appropriate plants. Water Parameters for the last 4 weeks have been pretty consistent at pH 7.5-7.6, ammonia 0-0.3, 0, 0, with a 5 gallon water change once per week. I am running my Finnex 24/7 light in the 24 hour day cycle simulation mode."

According to your own water parameters, your tank is NOT cycled. You should have 0ppm Ammonia, 0ppm Nitrite and between 1-20ppm Nitrate. Either it never finished cycling or it crashed after you believed it was cycled.

Please read up on the nitrogen cycle and fishless tank cycling.

I won't even touch on the rest at this time, I'll leave that to someone else.

I'm guessing my tank was cycled correctly. I cycled it over about a 6 week period. I got it to the point it could convert 3.5 ppm Ammonia to nitrates in about 24 hours (with 0 ammonia and 0 nitrites).

Ammonia and nitrite have always read 0 ppm except for one 0.3 ppm ammonia reading about 2 week after having fish. I'm guessing that it was user error or some fluke as it was back to 0 ppm half a week later in the next test. I'm guessing the nitrates are being consumed by the plants and that is why they are reading zero?

 

Snip

The nitrates were getting into the low 100's ppm during the fishless cycle, so I'm guessing the plants are now consuming it all as you suggest.

Thanks for the heads up on nitrate testing issues (fyI I am used the API liquid kit), I am doing all the bottle shaking that kit recommends for the nitrate test. I'll be extra careful doing the nitrate tests in the future; but I was definitely getting readings during the fishless cycle.

I didn't realize that java moss is a nitrate sponge and I do have a somewhat decent amount.

I will amend my fertilizer dosing schedule. I thought since I had a "low tech" tank with "low tech" plants I wouldn't have to really fertilize/excel much if at all. So I just figured that giving the plants a little extra couldn't hurt (which is why I used the reduced dosing).

I will reduce the light schedule, it is a shame because the 24/7 mode is beautiful...

Any thoughts on the filter being under powered even though the manufacturer says it should be more than adequate?

Thanks for your help

 

Snip

That starting intensity and duration you suggested sounds very reasonable. I'll give it a go. Any thoughts on doing a somewhat unusual lights on period of 3 hours in the morning (so I can feed/look at them before work). Then off for 8 hours. Then on for 5 hours in the evening (when I get home from work) Then off for 8 more hours overnight?

I'll say it again, that is shame the 24/7 mode can't be adjusted for intensity. It is awesome...

 

I wouldn't worry about AquaClear's being underpowered, they're actually a pretty darn good filter. If you're worried about not enough flow, you can always add a powerhead.