# algae+some stunted plants



## Frank Drebin (Sep 1, 2005)

Hi, I have a 72 liters tank. It's an old setup (almost 3 years) and I'm fighting against cianos.

Tank setup:
72 liters
Aquaclear 200 filter
CO2 (something between 20 and 30 ppm)
4x20w normal fluorescent (80 watts total) from 11am to 11pm

fertilization: 
Saturday: 70% water change + 1/4 teaspoon CaNO3 + 1/2 teaspoon KHCO3 (raise KH to ~ 2o) + 1 ml Seachem Flourish + 1 teaspoon magnesium sulfate
Sunday: 1/16 teaspoon KH2PO4
Monday: 1/4 teaspoon CaNO3 + 1/4 teaspoon K2SO4
Tuesday: 1/16 teaspoon KH2PO4

All the plants (and cianos  ) are growing well, except the higrophila polysperma and lilaeopsis brasiliensis.
They are both stunted under heavy light. 
Last week I did a 3 day blackout (without CO2), and they grow a bit during it. I also found out that when they are shaded they grow (very slowly, but grow).

Higros' stems seems to "break" easily.

Any ideas?


Thanks.


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## Laith (Sep 4, 2004)

I would say that the first thing you need to make sure of is that your CO2 is at a minimum of 30mg/l during the photoperiod. If you can only measure in a range of between 20 and 30mg/l then I'd suggest getting a better pH test.

The next problem I see is that you are only dosing 0.05mg/l of Fe (from the Flourish) once a week. I would increase this to at least 0.1mg/l every other day to start with.

You don't need to dose so much KH2PO4. You are dosing about 8mg/l of Phosphate with each dose.

You are also at 4.4wpg of light for 12 hours a day. Maybe try running just 3x 20w (giving you around 3.3wpg) for 10 hours a day? 4.4wpg is a lot of light...

I think the combination of the above is what is giving you some problems. Another thing that I've found helps in an established tank is to deep vacuum the substrate about once every year or so.


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## Laith (Sep 4, 2004)

Forgot: Welcome to APC!


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## hir0 (Nov 11, 2005)

you could try cutting your K2HSO4 in half (1/32 tsp) and dose that sun, tues, thurs. that's about what i dose for my 76L. also, I dose 1/8 tsp K2SO4 on the same schedule. Other than that, the only thing I'm not seeing as far as ferts go is Nitrates. I go with 1/4 tsp KNO3 3x a week. Not sure if my schedule is all that great, but my plants seem to like it.


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