[The Coffee]

Ok so I've had my 55g planted tank for about 18 months now. One of the first plants I put in when I got the tank was Vallisneria Spiralis, or Italian Vallisneria. It did really well and took over a large part of my background. I've even had to remove some of the daughter plants and plant them in my other tank.

Over the past month or so, I've noticed that a lot of the leaves have been turning yellow and dying off. 95% of the leaves that are dying are ones where the tops have been eaten off by fish or accidentally damaged by me when I cleaned the tank. This seems to be worse in older plants.

The new growth looks good and the other plants are doing well but I'm worried about the older leaves dying off on a large scale on the vals, especially on older plants. I'm having to remove dozens of them every day. This became especially bad after I did a blackout to get rid of some BGA.

So my question is, is it normal for leaves that have been cut or damaged at the top to die off like this on vals or is there something wrong?

Here's some info on my tank:

55g with 2x54W T5 HO 6400k lighting
DIY co2 giving ~20-25ppm
PH= 6.8, KH=5, GH=5, Nitrate= ~10-20ppm, Phosphate= ~1-1.5ppm
Dosing: Flourish Comprehensive Weekly, Equilibrium w/ wc weekly, Flourish Excel daily (since starting tank so I doubt this is affecting vals since it hasn't caused any melt in the past),

 

[DayOlder]

Flourish Excel daily (since starting tank so I doubt this is affecting vals since it hasn't caused any melt in the past),

By any chance did you increase your excel dosing when you were trying to get rid of your BGA? When I was doing daily dosing of excel my vals did not seem to mind but when I tripled my dose for BBA it melted all my vals. I don't even have any left in my tank anymore. That may have just been a coincidence but I don't think so.

 

[Raymond S.]

I had a 30L tank once long ago and being 16" tall it wasn't a very good tank for regular vals. I had no idea that they got 60" tall of course at that time. Well as each leaf would get close to the top I started cutting it off close to the surface. Each of those leaves would die. After almost a dozen had died I finally realized it was no coincidence and just pulled them out of the tank.
Looks like it may be common to most vals. It took less than a week/w the regular vals.
But the large numbers seems to say it's triggered by something different going on.

 

[The Coffee]

By any chance did you increase your excel dosing when you were trying to get rid of your BGA? When I was doing daily dosing of excel my vals did not seem to mind but when I tripled my dose for BBA it melted all my vals. I don't even have any left in my tank anymore. That may have just been a coincidence but I don't think so.

No I didn't increase the dosage. If anything, I'm using less than normal. I tried a spot trestment for the BGA but it didn't really help so I went with the blackout, which did help a lot.

 

[Zapins]

Pics are needed.

 

[The Coffee]

Interesting. Well it makes sense that it could simply be old leaves that have been cut or damaged are being killed off by the vals so they can make new leaves. Most of the ones that are turning yellow are like this. Just seems a bit weird that it would happen on such a large scale. Maybe the blackout triggered them to speed up growth and kill old leaves?

Anyway, here's some pics. I removed most of the bad leaves, but there is one or two left that can be seen pretty clearly.

 

[The Coffee]

Pics are needed.

See above.