Re: Aquatic Plants Digest V2 #84

>From: hermel at ibm_de
>Date: Thu, 18 Jul 1996 14:09:34 +0200 (DFT)
>Subject: Algae fighting
>Hi folks,
>I wonder if anybody can give me a tip on how to fight algae.
>I read a lot on the net already but nothing seems to work.

>Water is ph-controlled with a ph-meter and CO2-injection, ph is always 6.95.
>CO2 is about 20 mg/l. My hobby is to test the water parameters, here we go:
>nitrite <0.1 mg/l
>ammonia 0
>nitrate 15-20 mg/l
>O2 8 mg/l (temperature is 26-27C, should be close to 80 Fahrenheit)
>KH 5
>GH 9
>Some green thread algae are starting to grow (the type that looks like a
>short green fur) and some black brush algae (short and long), also green spot
>algae. The thread algae grow more in the regions closer to the light.
>My understanding was always that that algae come from high nitrate and
>phospate values, so I bought a phospate test kit yesterday, it's only
>0.1 mg/l. Maybe the nitrate is too high? I use a lot of reverse osmosis
>water and only some tab water for my water changes (30 liter every second
>because the tab water already contains 15 mg/l nitrate and I feed as little
>as possible.
>Is the nitrate the problem? Can I use a filter or something to discard
>the nitrate?

Your tank seems pretty healthy to me. Some algae of the types you describe
is to be expected in normal aquaria.

Nitrate & phosphate testing is tricky. It is difficult to determine
absoulte numbers. The best way I have found to monitor both N&P is to do
regular tests, (using the same kit brand) record the results, and compare
over time. Don't attempt to follow any recommendation for max nitrate
levels unless you are sure that the "method" (ion or nitrate-nitrogen) you
are using is the same as the recommendation.

The "thread" alga you describe have always decreased for me if I: 1. use a
phosphate remover resin, 2. increase the plant mass in the tank, and 3.
re-arranged the plants so that none are very close to the lights. I would
also not use any plant tabs except for laterite balls. Duplaplant is OK.

In general, use laterite near the roots for bog plants (ie. swords) and
liquid for aquatic plants (ie. hygrophilla).

Green spot algae is a "normal" situation. I reccommend Otocinclus Affinus
catfish in quantity (ie 6 individuals).

-Bill Brady Maryland USA