Lighting - how long should it be on ?

I have had conflicting advice on how long I should be running my light on my 90l. I understood too long meant algae so ran it only for an hour a day. Still had a lot of algae but not unmanageable.

I was told it wasn't enough and to run the light for 'at least' 10hrs which I did . Inevitable thick brown algae was the result (I had also started light feeding the plants - following advice from same source). I've been carefully removing the algae as best I can, cleaning plant leaves, decorations and glass but I have now been advised I've run the light too long.

What's best in terms of lighting for a 90l, very lightly planted minnow tank?

 

I had a lot of problems with algae but once I limited my light to 7 hrs, all algae problems cleared up.

 

I do 8 hours of light on my planted tanks. I have everything timed. I find consistency is key. So a timer would be a good start. $20 at a hardware store. If you have a routine that's the same each day it'll help your plant growth greatly.

How Old is your tank? Diatoms sounds like what you might have going on. It could possibly be silicates in your water. they feed off of it especially in newer systems. the algea could also be caused by higher nitrates and or insufficient water changes to remove excess nutrients, waste etc. What are your parameters if you have a test kit?

What type of light do you have? I've found on smaller tanks (you said you have a 90l) super high light isn't needed if you don't have tons of plants.

Outside of normal maintenance, there are good products that help with plant growth and algea issues. I personally use aquarium co-op's easy green, easy iron and easy carbon. The carbon in particular helps greatly to fight back algea. If you're not in the United states, any liquid carbon should get the job done.

 

The brown algae will be the result of 1 hours than 10 hours. Brown algae means a shortage of light instead of too long amd as mentioned often a problem in new set ups. 10 hrs normally will be great and needed for plants ro grow and use the ferts available.

Not many places in the world where there is one hour of light (and flourishing tropical plants)

 

I usually do a once weekly water change of about 10-20%. After parameters are fairly stable ( ammonia/nitrites-0. Nitrates-10. PH-8). The light is the big standard one that came with the tank which has been running now for about a year. We've had a few ups and downs over the months and I lost a lot of fish. I also don't seem able keep snails going in the tank which would have been my choice of defence