Hey guys, I went out of town Fri-Mon. When I left, my tank looked perfect. Everything was growing nicely, and all plants were deep green. While I was away, I asked my son to dose the tank and left him instructions. He's very responsible, so I know he dosed correctly. When I returned Monday morning, the dwarf hairgrass in the center of my tank was brown and some of the other hairgrass around the corners and front of the tank didn't look as vibrant. I was shocked that things could go south so quickly. About a week before I left, I added CO2. Everything seemed to be doing great with the CO2. The only thing different I did the day before leaving was install a ceramic disk nano diffuser that finally arrived. Before that, I was getting by with a piece of bamboo as an emergency diffuser. The nano ceramic disc may diffuse slightly more CO2 into the water, but I am still running it at the same 1 BPS.
I have a theory about what happened. Please let me know your thoughts. I did a water change just before leaving to reset the fertz in the water. When I did the water change, I turned down the filter flow to low to create less disturbance as the water level fell during the water change. I forgot to turn the flow back up before leaving. Do you think the lack of flow could have caused the die-off? Could it also be that the fertz that were added were concentrated toward the center, and with very little flow, they covered that area and burned the grass?
Here is everything I can think of to tell you:
Tank 6.6 Gallons (Petco)
Light: 1 T8 (medium to medium-high light in center due to shallow tank and substrate height). On 8 hrs per day with a mid-day siesta of a few hours
Fertilization: NPK even days, Flourish odd days, Osmocote under substrate
CO2: Pressurized, 1 BPS, on before lights-on, off before lights-off.
Water Params: Ammonia: 0 to .25 PPM, Nitrite: .5 PPM, Nitrate: 20 PPM, pH 6.6 while CO2 on, GH 30, KH 40, source is excellent well water
Substrate: Seachem Flourite supplemented with Osmocote underneath
No fauna.
Normally have mild surface agitation from HOB filter flow. This was greatly reduced while away due to lowering flow rate.
I also have some anubias nana 'petite' that appear to be yellowing at the tips.
Microswords and crypts appear to be unaffected. Look healthy.
Baby tears (not dwarf) appear to be basking in the CO2 glow. The tops are 50% larger than the bottoms. Look healthy.
Corrective measures up to this point:
50% water change
Dose NPK (1.2mL of each (Pfertz)
Cut dead and dying DHG down to substrate and remove trimmings.
Is there anything else I should do? Please help!