What nutrient excess causes this gray algae?

[CGGorman]

Strange branching filamenteous algae is in both my tanks, but is getting pretty serious in my 70. Only seems to grow on the Malaysian wood. The snails and Otos don't touch it.

Any idea what nutrient/mineral might be causing it?

Is it even algae?

 

[ringfinger]

My guess would be Staghorn algae. Can't seem to find much information on treatment.

 

[BlazerFRS]

Can it be mechanically removed?

 

[Simpte]

Deffinitely staghorn. The presence of this algae usually indicates a shortage of macro nutrients (and sometimes carbon dioxide). Because of this, it can be useful as an early warning that the plants are being underfertilized (APC). Manual removal and increasing macros will usually get rid of this algae.

 

[CGGorman]

Yeah, it comes off fairly easily with a brush, but it come right back in the same spots.

I'm running pressurized CO2 and keep it at about 20ppm with a pH controller. I'll check my nitrates and phosphates tonight. I received all the ferts Greg Watson offers about two weeks ago, but I wasn't sure where to start with the Macros, so I've been working on only the traces (CSM+B) for the last week. I've been dosing the recommended amount daily, waiting for the iron to become measurable.

Any advice on how to proceed?

 

[malkore]

How to proceed:

first, we need water parameters, mainly NO3 and PO4, since those nutrient imbalances cause 99% of algae blooms. You want a 10:1 nitrate to phosphate ratio to keep them balanced. For potassium, just dose 10ppm 2x a week, assuming weekly 50% waterchanges are being performed.

second, why are you running CO2 so low? I'd run it a little higher...25ppm as a bare minimum if your tank has 2.5wpg or more. I run my 75 gallon at 35-40ppm.

third, you may be overdosing iron. iron test kits suck...period. They typically cannot read accurately below 0.05ppm, and we only need 0.03ppm max. Some attribute thread algae to iron overdosing...but the final decision is still out on that...and besides, you have what appears to be staghorn algae, not thread.

 

[CGGorman]

What I was reading over at The Krib indicated I should be shooting for 1-1.5 ppm Iron...

Regardless, the staghorn has been present since the tank cycled...before I started dosing.

I have some baseline measurements, but don't know them off the top of my head. Besides, they are about two weeks old now. I know the last time I measured, both the chelated and free iron were zero. Nitrites and Ammonia were zero. I think Nitrates were about 20 ppm. I don't remember Phosphates, but it was low to nothing.

Actually, just knowing that 10:1 ratio is tremendously helpful!

When I say "how do I proceed", it's more of a methodology thing than details.

 

[malkore]

Ok. definitely retest the water. Its not uncommon for things to radically change, espeically if you had a deficiency in something like Potassium the last time you tested, it could cause NO3 and PO4 not be used, since the K was missing. Then you dose some K, and the plants soak up all the NO3 in 48 hours.

Learning how your tank likes to use the macros NPK will eventually allow you to just estimate what is needed. Just test more often for now, dose to keep thinks around 10:1, and don't worry so much about iron levels. If you dose some iron a couple times a week..you have enough. Its a trace nutrient. 1.0ppm is way too much iron. I think at 3ppm iron you start making live bearers sterile...not good.

 

[CGGorman]

Considering my Livebearer population has doubled in the month I've had them, I'm completely OK with a bit of sterilization!

10-4 on the NPK and Fe. Will take measurements and post them.

-------------------------------
Edit; 9 pm...

Test results:

Temp = 76 F
pH = 6.7
kH = 60 ppm CaCO2
gH = 160 ppm CaCO2
Phosphates = .8 ppm
Free iron = 0 ppm
Chel. iron = 0 ppm
NitrAte = 7 ppm
NitrIte = 0 ppm
Ammonia = 0 ppm

I added 1 tsp. of Sodium Bicarb. to raise the kH another 20 ppm. Nitrate/Phosphate is right around 10:1, but are they high enough?

Should I add potassium, I assume?

What say, all?

 

[Wizzard~Of~Ozz]

Yes, you need potassium, there is no test kit for it so as mentioned dose to 10PPM every week.

Your nitrate could use a bit of a boost, unless you are reading into "bringing out the reds" the PO4 is great, you don't want it to get too high and you can extend your NO3 to 16PPM without worrying about falling outside the "safe ratio".. (it's 10-20:1 ratio of NO3O4)

 

[CGGorman]

OK. I dosed enough Potassium Sulfate to increase the tank by 5 ppm.

I've got the sypmtom sheet from The Krib on nutrient deficiencies, so I'll keep an eye out for those.

How long should I wait to see results before deciding on another dose (of K or other)?


Thanks, all!

 

[czcz]

What I was reading over at The Krib indicated I should be shooting for 1-1.5 ppm Iron...

Are you sure this was not .1-.15ppm iron? It is a fairly modern concept to dose to .2ppm, and even today some will raise their eyebrows at a .3ppm dose. Greg Watson and Tom Barr have talked about dosing to 1.0ppm, but to me this is still risky. Since Fe level is used as a proxy for all other elements in CSM+B, you should address your dosing here.

As has been said, do not care about a non-reading on your Fe test. The standard trace mix is 1TBL Plantex in 500mL, 5mL/20gal dose. IIRC this is a dose of .2ppm. If you want to dose for target ppm (say .3ppm), the formulas are in the fertilization sticky as a reply. Post the volume of this tank here if you want to see the calcs instead.

How long should I wait to see results before deciding on another dose (of K or other)?

Assuming high light and perference to dose to measurement, best to test daily or every other day until you can predict N and P uptake. Most under high light end up dosing macros and traces 3-4 times a week on alternating days. You could add your K and bump up KH once a week at water change if you wanted. HTH

 

[malkore]

its 10ppm of K, two times per week. you'll see some suggestions of a target of 20ppm, but IME 10ppm after a water change, and another 10ppm 3 days after will maintain good K levels.

I would agree, nudge that nitrate up to 10-15ppm, and phosphate 1-1.5ppm

And yeah, the CO2 is a nudge under 20ppm, so increase that. I've accidentally run my CO2 at 100ppm for several days,a nd the only reason I found out I had high levels was from testing. The fish were fine...the plants loved it. I think you'll find 30ppm helps combat algae blooms...heck between adding more K, and bumping CO2 that algae may disappear in a couple weeks from that alone.

 

[CGGorman]

K.. Thanks!

The tank is 70 gallons with about 3" of substrate.

I'll dose another 10 ppm of K tonight and keep watching for calcium problems.

I'm keeping close tabs on kH to get my CO2 up w/o dropping pH any further.

 

[czcz]

Let's call your 70gal 60gals of water after displacement of substrate and stuff. Let's assume 1TBL of CSM+B to be 13.6grams per MatPat from SWOAPE/AGA's trials. (I only have and weighed CSM+B+Extra Fe.) Let's assume you want a somewhat rich mix, so you do not have to dose a lot of solution to reach your target ppm, and that you have a spare 500mL opaque bottle to store the mix. Let's make your target dose .2ppm Fe to be safe.

Mix (variables are in italics so you can mess with this for another mix if wanted):
mg CSM+B * (.0653mg Fe/mg CSM+B)/mL water = mg Fe/mL trace mix

3TBL CSM+B = 40800mg CSM+B

40800mg CSM+B * (.0653mg Fe/mg CSM+B)/500mL = 5.33mg Fe/mL trace mix

Dosing:
(target ppm * tank gal * 3.77L/gal)/(mg Fe/mL trace mix) = mL dose to reach target ppm

(.2ppm Fe * 60gal * 3.77L/gal)/(5.33mg Fe/mL trace mix) = 8.49mL dose

So, 3TBL of CSM+B in 500mL solution, with 8.5mL dose adds .2ppm Fe into your tank. Let's pretend you want to make your life easier by dosing an even 10mL from this trace mix: you would be dosing .24 ppm Fe.

(mL dose * mg Fe/mL trace mix)/(tank gal * 3.77L/gal) = Fe ppm

(10mL * 5.33mg Fe/mL trace mix)/(60gal * 3.77L/gal) = .236ppm Fe

Make sense?