Algae bloom

[michaelwgroves]

I have a 1000L planted tank, CO injection, feed plants daily, 12 hours of light, nothing changed in last year.
However, I've been struggling with the amount of time I have to spend every week pruning plants, so I decided to stop feeding. This helped a lot with maintenance. I then decide to remove some old very well established plants as they were blocking light to substrate.
I thought I would then restart feeding at 50%.
Within 3 days the tank has an algae bloom. I stopped plant feeding, reduced light, and started 20% water changes 2-3 times a week. After 3 weeks there is no improvement. I've now decided to feed plants as per previous doses and lights back to 12 hours. in a hope with vigorous plant growth will see off algae. I also guessed it might be phosphates, so bought every phosphate filter you can buy for my Fluval FX5. Then bought tester, but apparently I have no phosphates, 0 nitrates and 0 nitrite. Stocking levels are low

I'm on day 4 of phosphates filters and normal lights/plant feeding, but no difference. It's dual aspect tank, and I can't see through it. I also use polishing pad for max filtration.

I'm lost for idea's, any thoughts?

Thanks,

 

[Colin_T]

Pictures of the tank and algae so we know what type it is?

If you are concerned about phosphates in the tank, just do a massive (90%) water change to dilute any nutrients in the tank and fertilise after that.

You probably won't get any ammonia, nitrite or nitrate in a heavily planted tank with fast growing plants due to the plants sucking up the ammonia. If there's no ammonia there won't be any nitrite or nitrate.

 

[Rusty_Shackleford]

Is it green water ie, single celled free floating algae you're having an issue with, or algae on plants, glass etc?

 

[michaelwgroves]

It’s free floating particles, glass is clean.

 

[Rusty_Shackleford]

It’s free floating particles, glass is clean.
View attachment 372248

OK this is an easy one. Get yourself a UV clarifier/sterilizer. It will clear that tank in 7-10 days tops.
I went through the same thing myself earlier this spring. My cause was getting new lights and having the lights too bright. I tried everything, I stopped using fertilizer, blacked out the tank for a week, 50% water changes every other day. What worked was the UV.
Now you still need to find the cause of why. In your case it may be that you stopped fertilizing which made your plants weaker. Plants like things very consistent. I find when you change in a plants routine like light or fertilizing there is some sort of reaction in response to those conditions.

Edit: Check this out. Feel free to look at the whole thread.
Post in thread 'Aquatop SP7-UV Submersible UV Filter' https://www.fishforums.net/threads/aquatop-sp7-uv-submersible-uv-filter.496924/post-4366008