• You are viewing the forum as a Guest, please login (you can use your Facebook, Twitter, Google or Microsoft account to login) or register using this link: Log in or Sign Up

Would a sudden drop in lighting trigger diatoms in an established tank?

A

Ajm200

Member
Joined
19 Feb 2010
Messages
531
Location
London
Hi, My tank has been running for years and I'm suddenly seeing diatoms on plant leaves this week. Not a serious outbreak but noticeable. I know it will resolve itself as it has in the past when I've moved stuff about or added too many fish at once. I'm just curious about the possible cause this time.

Only changes have been:

A new FX6 filter to replace an EFX 600 that was leaking. All biomedia was moved across to temporary filters immediately then placed into the FX6 within 24 hours. Only the sponges were binned. The filter is one of 3 on the tank. The others are packed with biomedia and have not been touched during this time. They were cleaned 2 and 3 months ago. The filters are normally cleaned one at a time on a 3 month cycle so nothing unusual there. I've seen no ammonia in the tank since the change. I was doing daily checks at first.

The other change was a lighting unit dying just before Christmas. This reduced the light during the middle 4 hours of the lighting period by 2 x 54w HO T5s. The tank is now running on 2 x 54w for 8 hours.

Tank is 5x2x2
I've added no fish or plants.
Water changes happen weekly
Ferts and liquid co2 are added daily at lights on and measured carefully.
The substrate hadn't been disturbed

What do you think?
 
Last edited:
For further info.

The plants are
swords (regularly eaten by a catfish so not big as they are trimmed of damaged leaves weekly)
A variety of crypts
A variety of Anubias on wood

The fish are
10 angelfish (about 3.5 inches so not full grown)
Two rainbow fish (full grown)
3 kribensis
5 cories
10 neon tetra (the ones I and the angelfish can't catch.)
A bristle nose catfish (with a taste for sword plants)

Not a lot for a 500l tank
I can't see anything rotting in the tank and the fish are fed sparingly
 
When these things happen, you have to ask your self what has changed. Filter exchange sounds like the most obvious cause even though you were careful, but don't dwell on it, just give it time.
 
Can't blame silicates for this one. Perhaps this anecdote shoes our lack of understanding of Algae.
 
You must log in or register to reply here.
Back
Top