Identify Algae + cause + solution?`


Plant Guru Team
Lifetime Member
Sep 23, 2007
South Florida
Hey all,

I have a species of algae that I would like to identify, understand the cause(s) of, and establish any remedies/solutions.

I have only had this algae since I started with my 3X150w MH setup. I first had 14k bulbs and NO EI, but have since switched to EI and 6500k bulbs. Never had it with 240 watts of flourescent.......

It only grows on the driftwood, pic attached, and every now and then a larger piece of gravel.

Actually builds some nice shapes on wood as it grows. I pinch off with my fingers once a month to keep it 'trimmed'. I get a huge clump by the time I am done. Grows very thick, and is tough to totally remove.

It looks nice, fish like to eat it, and browse for amano shrimp larvae (there are tons of them in there), and it doesn't bother me, but I would like to understand it better.

I want to cover some of my wood with Riccia and want to ensure it will not get covered/crowded out by this algae.

I am on the following dosing sched:

+ 3.0 tsp KN03 3x a week (N)
+ 1.0 tsp KH2P04 3x a week (P)
+ 50 ml Trace 3x a week
60-75% weekly water change with Prime

Sunday - water change Main Fert
Monday - Trace
Tuesday - Main Fert
Wednesday - Trace
Thursday - Main Fert
Friday - Trace
Saturday - Rest & Enjoy!

180 gallon tank with trickle filter and sump. Flourite substrate. Tank is well established at over 5 years.

Thanks in advance for all of your help.


Tom Barr

Staff member
Jan 23, 2005
It's actually a pretty desirable algae, and type of Caldophora I believe from the pic.
Few critters will eat it, and it's much like the Algae Clado balls.

Have you had any Clado balls in the past?
They will form on larger gravel pieces.

You can do a good sized water change and spot treat with Excel.
Scrub with a brush etc, VACUUM WELL, etc.

I like this alga and leave it if I have it.
It tends to be slow growing but only becomes a pest when you have it go sexual and the spores land all over.

Regarding the ferts:
Try 1.5 tsp in stead of 3 per dose if I read that right for KNO3.
3/4 for PO4
50-70mls of TMG 3x a week
GH etc?
Might add some Mg, say 2 tsp after water change.

Tom Barr


Plant Guru Team
Lifetime Member
Sep 23, 2007
South Florida
Hi Tom,

Thanks for the quick reply!

I have never had Clado balls before. Only had this algae when I switched to MH lighting......

My Anomalochromis thomasi and Laetacara dorsigeri dwarfs like to eat it, as well as my Bosemani rainbows. I have definitely seen them eat plenty of it as well as forage in it......surprised that you have not had the same experience?? SAE and corys love to browse as well as the dwarfs....

As stated I like it as well and will keep some as it is attractive, but wanted to replace some of it, as the wood is very nice, but you can't tell the shape any more as it is covered by this...... It also pearls which adds to the attraction.......

Yes, you read that right, 3 tsp of Kno3 as it is a 180 gallon.

I had gotten the following from the EI thread:

100 - 125 Gallon Aquarium
+/- 1 1/2 tsp KN03 3x a week N Nitrogen
+/- ½ tsp KH2P04 3x a week P Phosphorous
+/- ½ tsp (30ml) Trace 3x a week
50% weekly water change

So I had adjusted my dosing accordingly for the larger tank and 25 gallon sump.....

I do use TMG and like it a lot.

I will dose as you suggest, but will say that I have had surface scum the last several weeks, which I understand is a fert deficiency?

Yet you advise to go lower than my current dosing? Sorry, but could you explain that a little? Seems to be at odds IMO, but do not know much about this.

Other measurements:

2 Boyu Type I drop checkers show green color @ 4-5 kh reference solution = 30-40 ppm. All plants pearl including those at the bottom, so feel it is distributing well.

Ph is 6.6 according to SMS meter and matched to DC color solution chart

GH 140-160 MG/l CaC03
KH 90-100 mg/L

I do not add anything else to the tap water.

Not sure what the MG reading you want is????

Tank is doing VERY well other than surface scum (very recent as stated) and the algae on the wood.

Recently removed about 20% of biomass as the H. difformis and Bacopa Carolinia was taking over and thought it would help with any nute deficiency as the tank would need less, but no diff yet...........

I have been averaging about 75% WC weekly for at least the last 6 weeks.

I will try scrubbing a piece and look into the Excel......

Thanks again for all of the help.