Re:Red algae and green water

>David Whittaker wrote, Mon, 7 Aug 1995 07:57:32 -0400:
>>I believe that it was Paul Kombholtz who recently said.....
>>>I have noticed that red algae (which normally looks dark green) turns
>>>bright red when exposed to hot water. Take a sample and boil it if you
>>>want to be sure of what you're dealing with. You can also use tap water
>>>as long as it gets reasonably hot.
>>Well, I boiled an anubias blade with a bit of red algae attached to
>>it for a couple of minutes. The algae was dark green both before and
>>after the treatment. It was about 4 mm in length and appeared similar
>>to what The Optimum Aquarium labels red algae on page 123, item #2.
>>What gives? Any comments?
>>My apologies to Paul if the attribution is incorrect.
>It wasn't me who said that.  I think it was Glen Osterhout in Aquatic Plants
>digext VI, # 166.  I've been harping that y'all should not tolerate red algae
>or any other kind of hair algae, and that you can get rid of it forever with
>5% bleach.

Steven Hicks wrote, Mon, 7 Aug 1995 11:36:32 -0400 (EDT)

>>I'm trying to be patient, but I am having a horrible time with green water in
>>my 2-3 month old planted tank.  Details are listed at the bottom of this
>>message, but basically after I added two Vitalites (I already had two Tritons)
>>I got great plant growth, along with algae.
>>At first it was just green algae on the glass, which was no problem as I
>>have 3 SAE's to keep it under control.  Next over a 2-3 day period my
>>water turned green as my nitrates dropped from 3.0ppm to unmeasurable.
>>Assuming that excess light and nitrates were the problem, I removed one
>>Vitalite, lowered 'daylight' time from 11 hours to 9, and began doing
>>25% water changes every couple of days.
>>Then I had a minor disaster.  One of my timers broke (unknown to me) just
>>before I went away for a couple of days.  One Triton/Vitalite combo was on
>>for about 36 hours solid.  When I returned my tank was almost opaque green.
>>I did a 50% water change and things look a bit better.  Should I just continue
>>with the water changes and reduced light, or will it require something more
>>to get rid of the green water?  One thing I'm concerned about is that when
>>I do a water change, the tap water treated with de-clorinator tests positive
>>for ammonia.  Assuming my bio-filter just converts the ammonia into nitrates,
>>am I ADDING food for the green water 'algae' by doing water changes?
>>More details on my tank below:

----details snipped---

>>I have three very active and growing 3" SAE's (no other fish) which I do not
>>feed.  All my plants are growing and producing O2 bubbles. Thanks for any help
>>you can give.
I have always wondered why more people trying to grow plants with fish
havn't had persistant green water problems.  I thought that perhaps they
had filtration systems that removed the algae. I don't use mechanical
filters, and most of my tanks don't have fish so that I can use Daphnia to
keep the water clear.  I do have a 55 gallon with both plants and fish lit
by two ordinary 48 inch fluorescent tubes.  That is not much light by
today's standerds, but it is more than enough to support green water.  I
had a persistant green water problem with this tank, and I finally got rid
of it by taking all the fish out, indroducing Daphnia, and, after the water
had been clear for about a month and the plants had grown a lot more,
returning the fish.  The tank has stayed clear now for several years.  I
have only three swordtails and one platy in this tank and it is crowded
with plants. I think that the high ratio of plants to fish is important in
preventing the return of the green water.

I am not surprised by your observation that nitrates have dropped to zero.
Green water algae soak up nutrients like crazy.  I have never gotten a
reading with measurable nitrates when I have had green water.  It is a
common misconception that green water is a sign of overly high nutrients.
Actually a tank with green water is more likely to be very low in

Good luck, and keep us all informed.

Paul Krombholz