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Re: Thread algae

Hi George and everybody,

regarding:

>> > - light on for 4 hours
>> > - light off for 2-4 hours (2 hrs. seems to be too little..)
>> > - light on for 6-8 hours
>> >Total:10-12 hours of light within a period of 12-16 hours.
>> 
>> Has anybody tried this strategy against thread algae?
>
>It didn't seem to affect any of our algae but we found it an effective
>cure for Rotola macrandra and other high light plants, i.e., we lost
>some very robust groves of these plants by messing with the light
>cycle.  
>
>George Booth in Snowy Colorado

I have my sort of Dupla style tank set up since May now
and it's really a very pretty sight. Most plants grow
well and the fish are doing great, especially the
discus are doing very well now after some starting
trouble caused by flagellate infested frozen
bloodworms. But that's another story.
The tank went through different stages of various
algae, mainly green types. They all went away or are
under excellent control by the SAEs and ancistrus.
However, there is a persistent problem with thread
algae (the green, spider web like, hairy stuff which
makes long, well, 'threads') and now I'm out of ideas
for fighting them. To keep the tank looking nicely, I
have to harvest them every other day or every third
day. They have killed just about all the fragile plants
like Rotala wallichii or Limnophilia. I have
pracitcally zero other algae than the thread algae.
Haven't cleaned the front glass in months (this has
been different when the tank started).
Here are some of the tank's data:

150x60x60 cm, 540 liters (140 gal), w/d filter, no
peat, buffers or funny stuff. Plain substrate (about 3
mm) with some laterita balls (Amtra) added later.
Substrate heating cables 'Dennerle style' (50 W). The
water turnover is high, but I've directed and spread
the outflow in such a way as to minimize current. There
is no visible current now.

2x150W MH (HQI) lights. I don't know which kind of
bulbs, but they are of slightly different light colour.
I have reduced the daily light cycle to 8 h Mon-Fri and
10 H Sat and Sun. I'd hate to go lower than that. It's
kind of suprising to me that the plants are still doing
well anyway. But I have to admit I don't have any real
high light plants, except for maybe Ludwigia glandulosa
(which is growing very well, but noticeably better when
the stem reaches near the surface). Most of my plants
would be considered 'moderate light plants'. The tank
is rather densly planted with an even mixture between
fast and slow growing species.

Water temp is 28.0 to 28.3 Celcius (82-83 F), pH CO2
regulated at 7.3, GH 15, KH 10, NH3/4=n.d (not
detectable), NO2=n.d, NO3<12.5 mg/l, PO4=n.d, Fe barely
detectable (<0.05 mg/l). Water changes 150 l (25% if
you add the volume of the w/d filter) every week. Trace
elements from Dupla at less than the recommended dose:
2 tablets (meant for 50 l each) at every water change
and 7 drops of the daily stuff. I am trying to stay on
the low side with the iron, since George reported
increased thread algae growth with higher iron levels.

The fish load of the tank is light to moderate. The
discus are still young and come from local breeders, so
they're used to the hard water, but I have tried peat
anyway. But it takes A LOT of peat with such a tank and
a KH of 10 to get any effect, so I gave up on it.

So, anybody got any ideas? I think I'm kind of on the
low side with light and trace elements. One thing I can
think of would be the use of a RO unit to significantly
lower hardness and alkalinity and bring down the pH
below 7.0. Cost isn't really the factor why I haven't
tried this, it's more of a problem with storing a lot
of water in our relatively small apartement and with
significantly increasing the work load of the weekly
water changes.

Sorry for the long post, but instead of many
questions/answers going back and forth I thought I'd
provide as much info as possible.

Happy new year from Munich, 

Michael





 _________________________________________________________
|                       |                                 |
|Michael Irlbeck        |  u7211aa at sunmail_lrz-muenchen.de|
|Anaesthesiology        |                                 |
|University of Munich   |                  CIS:100277,343 |
|_______________________|_________________________________|