Unknown defficiency and black algae trouble

[fishb0ne]

Here are some details:
Tank - 10 gallons
Substrate - Eco complete
Lighting: 10w, 8 hours a day from 9:30 AM to 5:30 PM. The tank is next to a window [not in front] and there is a curtain in between so direct light is at a minimum, if any
Plants - java fern, java moss and a bunch of crypts, some pennywort, etc
Water changes: rather large, about 40% weekly

Water parameters:
Ammonia: 0
Nitrites: 0
Nitrates: always below 20ppt
pH: 8.4
KH and GH not sure, haven't tested in a while, but I have hard water
Phosphates: on the high side, I've had it spike to 2.0, for now it is a 1.0 or below. I am trying to get them under control

Dosing:
Flourish - .8-1ml at water change
Flourish Trace - mid-week, 1ml
Flourish Excel - 4ml at water change, then 1ml every other day
Flourish Potassium - 1ml twice a week

Defficiencies:
Well, for the most part the Java is fine but my crypts, although since I've started dosing the plants exploded, ONE of the nutrients above is borderline inadequate. Sometimes I'll get holes in the plants which I haven't had in a while but right now old leaves are curling up around the sides. The young ones come out nice, strong and flat but older leaves wither by curling.

I think my micronutrients are fine as the plants are constantly shootin' up a bunch of leaves, but I can't seem to manage to KEEP them healthy. What do you suggest I change or do?

In addition to all this, I have a rather bad case of black algae that looks like, well, black rust. How do I get rid of this, I've read that it's pretty resistand. Someone mentioned dosing with Maracyn?!?

Here are some pics
Picasa Web Albums - fishbone - 10 Gallon Fre...
Picasa Web Albums - fishbone - 10 Gallon Fre...
Picasa Web Albums - fishbone - 10 Gallon Fre...

 

[Purrbox]

Sounds like a Potassium deficiency. I'd try upping your Potassium dosing. Make sure that you're dosing at least 10-20ppm per week.

Does the algae brush off easily? Is it slimy? More details please.

 

[neilanh]

Not sure about the algae, as I don't think I've ever seen that one.

The holes in the leaves is a very strong symptom of a potassium deficiency. The nice thing about K is that it's hard to overdose it and cause any damage, so you can up your dosage without too much fear of adverse sideeffects.

 

[fishb0ne]

I admit I've been light on potassium dosing, I haven't been following directions which say 2-3 times per week. I will dose 3 times then instead of 2.

The black algae stuff is ... interesting. I've read it can be due to low nitrates and possibly low oxygen. The only thing I can tell you is that this stuff has started propagating more once I started dosing Flourish Excel daily instead of every other day. I will go back to every other day, at least for now. It is just like brown algae, like rust, but black. It first showed up on the stems of my pathetic-looking brazillian pennywort, I thought it was some sort of necrosis and left it alone, hoping it would bounce back up. Then it started propagating. It's not fillamentous or slimy and it's very hard to scrape off, almost to the point of damaging the actual leaves. I think I'll have to prune the affected leaves.

 

[neilanh]

I agree, get the affected leaves out of the tank.

That's interesting the more excel you put in the worse it gets. I was gonna say to up your dosage for a bit and see what happens, but I guess maybe that's not the right answer.

 

[travis simonson]

Yikes, that looks like a vicious case of the same algae I've gotten in my hard water planted ARLC tank. It only affects certain plants, and it appears as a black surface algae on leaves and stems that does resemble rust. I suspect it may have something to do with the high amount of carbonates present in hard water because I've never run into it in my soft water planted tanks.

I think it is a variant of black brush algae because it seems to grow best in areas of low circulation where O2 levels may be lower than the rest of the tank and CO2 levels may fluctuate a bit. I've had good luck spot dosing it with Excel. I use a pipette and just squirt some directly onto the affected leaves. Double dosing with Excel for a week also seems to keep it in check or drive it back.

But here's the Catch-22: dosing with Excel in a heavily planted tank can lead to low (possibly dangerously low) nighttime O2 levels, which in turn, can boost the growth of more black algae. I've tested this a couple of times in my tank. I dosed Excel at regular levels in the morning. After lights out at night I tested O2 levels every hour (yes, I stayed up all night just to test my water) with a LaMotte O2 test kit. At lights-out my O2 levels were near 7.5 ppm (equivalent to about 90% O2 saturation at 80 degrees F). Over the course of the night O2 steadily dropped, reaching a low point of 2.5 ppm just before lights-on, well below acceptable (or safe) levels. My fish were gasping at the surface in the morning (which was what led me to test the water in the first place) due to the low O2.

Heres my theory: Plants take up CO2 and give off O2 during daytime photosynthesis, where light energy is stored as sugars in the plant tissues; at night the cycle reverses and the oxidative process releases the energy stored during photosynthesis by converting the sugars to CO2 and water, using environmental O2 in the process. In a heavily planted tank, this process can consume a great deal of the available O2. When photosynthetic sugar production is supercharged with Excel's organic carbon source, even more O2 is consumed at night when the carbon in the glucose bonds with O2 to form CO2. I suspect that Excel may drive the uptake of O2 during the oxidative process to the point where, in an environment containing a fixed amount of O2 like an aquarium, levels become so depleted that they can have serious negative effects on the lifeforms in the tank.

I have only a layman's understanding of the carbon cycle and my interpretation may be entirely incorrect. However, if my theory holds true, it can explain some of the problems I have had when using Excel. Heavily depleted O2 levels occurring as a result of the spiking of the oxidative process by Excel's abundance of available carbon lead to: 1] respiratory distress and possibly death due to asphyxiation in fish and invertebrates; 2] low and/or fluctuating O2 levels which contribute to conditions favorable to the formation of black algae. Observation #2 illustrates the Catch-22: using Excel to treat black algae may actually contribute to the formation of more black algae because of its negative effect on nighttime O2 levels in heavily planted tanks.

Repeated experience has shown me that there are two courses of action to avoid this problem: 1] discontinuing the use of Excel which prevents the dangerous drop in nighttime O2 levels after 48-72 hours have passed and the Excel has left the system; 2] beginning lights-out aeration of the tank to counteract the O2 depletion caused by Excel. Option 2 has worked wonders for me. When my lights go out, my airstones turn on and run until an hour before lights-on in the morning, providing the tank with a ready supply of O2 and counteracting the O2 depletion caused by Excel's effect on the carbon cycle. Since I've started this regimen I have not had any problems with gasping fish and my black rust algae woes have almost completely disappeared.

Wow, it sure took me a long time just to tell you to try running an airstone at night

 

[jsoong]

Travis: Why don't you leave the airstone on 24/7? If you are not injecting CO2, there is no advantage in having low surface turbulance .... you are not off gassing injected CO2, and having lots of flow in the tank will equilibrate the tank's gases to atmosphere, making for much more stable O2 & CO2 levels, and less dead spots.

back to the original post - that sounds like the BBA that I had been battling for the last 2 years & finally getting it under control. I have tried tearing down the tank & bleaching everything, adding KNO3, increasing flow, dosing Excel, changing lights, duration .... all to no avail.

What finally got this beast under control was: Dosing Excel at doubled the initial (loading) dose for 3 days straight to kill off the bulk of the BBA. Then add a LOT of fast growing plants (hygros & hornwort) to fill up at least half the tank space. After a large water change (to reset everything), I changed my dosing regime to: pwc every 2 weeks (20%) - much less than what I had been doing, substrate ferts only, and Excel at maintanance dose ONLY after a pwc (rather than daily). So far I am BBA free for 6 months (fingers crossed). I don't know if my regime even make sense or not, but it is working for me.

 

[travis simonson]

Travis: Why don't you leave the airstone on 24/7? If you are not injecting CO2 . . .

Ah, but I am injecting CO2. My tank is awash in a sea of carbon Although I use Excel in combination with CO2 mainly for its algicidal benefits.