Black spots

Lachlan

I just started my plants a few weeks ago, and they started great, but now they're all getting some black (or possibly very dark brown) spots on their leaves. Here is some info:

Plants:
Jungle Val, Amazon/Argentinian Sword, Aquatic Fern, Green Myrio
pH: ~7.5
KH: 12 dH
GH: 3 dH
Temp 78-82
NO3: 10ppm
Filters: two penguin 330's with activated carbon in the baskets
Substrate: Eco complete
Additives: Flourish 1x per week, Excel 4x per week

Jay

Hey Lachlan,

Light? type and watts per gallon

How long are they on.

Flourish Comprehensive could be increased to every other day
Excel needs to be dosed daily
You have a little NO3 but I see no mention of K or PO4
Your GH is a little low and could use a boost

The plants are telling you they are in trouble.

Regards,
Jay

Lachlan

Light is 265W CF. half are 10K and half are actinic. Not my first choice but I got a good deal on them. All are on 10 hrs/day; actinics are on an additional 1 hr on either end, mostly for mood lighting. I have no idea how to measure my potassium, I've never seen a potassium test. I don't add any but I get K+ from my water softener. I don't add phosphorous either, so its whatever they're getting from fish waste. There's probably about 20 fish in a 90-gal aquarium, including two fecarific plecos. NO3 measurement is post-water change, so there seems to be plenty of that. There's a little green algae growing on the glass directly below the lights. What's a good GH?

gregpape23

I'm not really a plant person but I think a good GH s like 6-12.