06-16-2020, 06:22 PM
Join Date: Mar 2007
Location: Southern Ontario, Canada
| | Can an older tank recover from algae?
My 20g is around 10 years old. Up until two years ago, my tank was doing very well. The Crypts took over and turned the tank into a jungle and aside from diatoms at startup and some green slime on the glass top, I never had any problems with algae.
Some info about the tank before and after the algae. I used fluorescent tube lighting(one 6,500 and one 8,000 kelvin 17 watt bulbs) and the filter was a HOB called Marina by Hagen. The filter was just for circulation and the flow could be adjusted to a strong current to a trickle.
Ammonia and nitrite were/are at zero
Nitrate has always been 5-10ppm
Phosphates stay fixed at 2ppm
My water is hard and the pH is between 7-8
I always feed my fish twice a day with a bit extra for snails and plants
Lights are on for 11 hours a day
Two years ago, that started to change when I switched the noisy, messy HOB that produced a very mild current with a powerhead and my last 8,000K bulb blew. I can't seem to find any 24" T8's in 8,000K so I got a 10,000K instead. That's when I started to notice a green dusting on some of the gravel(I'm assuming it's GDA) and my crypts started to move away from the powerhead and thinned out a lot.
There was just a tiny bit of algae so I wasn't too concerned. Early this year is when I started to get diatoms again and the light green dust is on the glass now but not as much as the gravel. My crypts also started showing what looked like an iron and potassium deficiency and they weren't growing very well in general and I can't remember the last time I had a new runner from it. I have since treated the deficiencies and there is a lot more new, dark green growth on my crypts but the algae remains. Over a month ago, I removed the powerhead and am now using an air decoration for circulation. I also now have a bit of frogbit from when I bought a few RCS a few weeks ago.
Is it possible for my tank to recover from this? I don't know why I would be getting diatoms now and I haven't come across any actual causes for GDA. Could it have been from the change in the lighting? Aside from all of this, everyone in the tank seems to be happy. I wouldn't really care so much if it was just diatoms I was dealing with but the GDA is something I want gone.
Last edited by Red_Rose; 06-16-2020 at 06:26 PM..