Help save my tank--20gal planted med-high light - The Planted Tank Forum
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post #1 of 4 (permalink) Old 02-22-2014, 02:59 PM Thread Starter
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Help save my tank--20gal planted med-high light

Hey everyone--thanks for reading!

I'm a beginner aquascape hobbyist, and I've been working on this 20gal since fall semester. Needless to say, running a high-tech tank while in school is tough--I had a professor watch my tank over winter break, and even though I had written out instructions for dosing ferts and had set the lights to timers, when I got it back I lost a couple fish and almost all my plants--basically planted tank armageddon

Before armageddon I had:
  • dwarf hairgrass
  • dwarf baby tears
  • red rubin
  • ludwigia
  • narrow leaf chain swords
And they all did pretty well (except the hairgrass).

Post armageddon, my narrow leaf chain swords and red rubin survived and are growing fine, though the ludwigia isn't doing so well.
Also in the tank are two nerites snails, 7 harlequin rasboras, and one albino bristlenose pleco.

I've planted some low-light plants--as soon as the semester is over I'm going to transition to a low-tech, non-CO2 tank to save on electricity and because I'll probably be moving around a lot.

Current plants include
  • narrow leaf chain swords
  • red rubin
  • java fern
  • water wisteria
  • crypts
  • ludwigia

20gal tall
Flourite substrate
up to 72W lighting--currently running 48W X 6hrs with 2hrs 72W "noon" lighting in the middle (fixture has 3X24W T5 HO bulbs, so I run a combination of 2 and 3 bulbs at a time)
more on lighting--that adds up to 21.6WpG/day (a bit less than the 24WpG/day suggested by Green Leaf Aquariums)
DIY CO2 out of a 2L sprite bottle

Water Params (tested just before posting this)
pH 7.4-7.6
Ammonia 0
Nitrites 0
Nitrates ~30ppm (is this high?)
Temp 76F (I recently broke the thermometer, but it's consistently around there with the heater I have)

2mL macros daily (solution mixed from Green Leaf Aquarium's macro pack)
1mL seachem flourish comprehensive three days a week

The bottom line is that I'm fighting an uphill battle with algae--some mean velvet/dark green algae.
What should I do to get rid of it? Get some ottos? Lower lights or ferts or both? I really respect all the experts on this forum, so I'm open to all advice and learning
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post #2 of 4 (permalink) Old 02-22-2014, 03:35 PM
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I think a hint to what is "off" would be to figure out what caused the "armageddon". Were the plants doing well before? Was algae forming? From the plants you have listed I don't think you need as much light and equipment and CO2, but I'm sure it doesn't hurt, just more to balance. Algae is a sign one of the three pillars, light, carbon or other nutrients is off. I would think you just have too much light. For example, I have a dirt low tech tank and my Wisteria has exploded with almost half the light intensity.

In short there are a few more necessary details. How long since you restated the tank? Algae is pretty normal for new or establishing tanks. Also, how are the plants growing? If the java ferns and swords are growing faster than about one leaf per week you are probably in the high light area as they usually grow pretty slow. They are capable of growing in the 1-2watts per gallon range for example. How is the Wisteria growing? If all is well it should basically be uncontrollable. If it is struggling you know something besides light is lacking, probably not CO2 if you have a system so maybe you need to look at how you are fertilizing. There are a lot of factors, but I have a feeling the algae is due to an over abundance of nutrients particularly your nitrates.
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post #3 of 4 (permalink) Old 02-22-2014, 04:36 PM Thread Starter
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Fishumms, thanks for the reply!

I reset the tank about 4 weeks ago. I'd say the java ferns and swords are growing at a good, steady rate like you said. Crypts and wisteria are doing pretty well too--the tops of the wisteria have really wide leaves and are lush and sprouting new growth happily, though the lower leaves are struggling against algae.

This tank has been tricky to balance since day one. As per your advice, I'll reduce lighting and ferts and see how that goes for a couple weeks. I think that makes sense because I my tank is only lightly-planted, especially without any large background plants.

Couple of follow up questions:

1. I'll try dosing 1mL macro daily and 1mL micro twice weekly, and bring down the light to 48W X 6hrs, without the "noon" lighting of 72W--does that sound about right, and will that lower the nitrates?

2. (a) What would be the best way to manually remove algae--light gravel vac? or just brushing it off with a sponge? (b) how often, if at all, should I be doing water changes and/or gravel vacuuming?

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post #4 of 4 (permalink) Old 02-23-2014, 02:11 PM
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I'd say at this point you will just have to "try and see". Sometimes tanks take awhile to figure out. If the plants are doing well I'm going to guess they are getting too much light. At a certain point the plants tap out either they used up the CO2 for the day, or all the nutrients but also, after about 8 hours most plants get "tired". It is this timeframe algae uses to it's advantage. It needs less light/ nutrients/ C02 than the plants. If you go to low tech I would suggest a 5 hour on 4 hour off 5 hour on and then "night" arrangement for the lights. It allows the plants a moment to rebuild CO2 in the water so they use up nutrients more efficiently for the whole second 5 hours. Also, I would suggest looking at Diana Walstad's book. I think I spelt that right.

Right now I have a 55 gallon with hair algae problems. It is low tech, no fertz, or C02. Half the lights come on for an hour, then all the lights for 2 hours, then half lights for 2 hours, then off for 4 hours, then the process repeats itself. This just seems to be how this tank needs to be. The lights are simple shop lights with 5000K 24W CFLs.

As a practical answer to your tank, I would personally try to bring down the light intensity. Clean the algae, choose an alteration and see if it comes back. Since your situation plants aren't struggling but algae is forming I think you have room and time and probably aren't as far off as you think.

As I read it your plants do well with only a 6 hour photo period, but there is algae. This to me points to the light being too bright, but I would also lower the fertz as well since the plants are not showing a sign of deficiency. Another help is fast growing plants. Anacharis or other stem plants. If you want to brave it, duck weed would probably help as well.

Algae afflicts us all, and even in long established tanks it can occur for whatever reason at any time. Good luck.
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20 gallon tall, algae help

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