lake_tuna

I did huge trim recently and saw that older leaves have black marks/spots all over them. What nutrients are missing?

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DutchMuch

Cant see to clearly in the pic, but if your plants where growing fairly thick, then that to me would be your issue is that you just weren't getting enough light down to the bottom layer of leaves.

hoppycalif

That looks like algae to me. What are your tank dimensions, what light fixture are you using, and do you use CO2 (how do you diffuse it into the water.)

Seattle_Aquarist

Hi lake_tuna,

What ferts are you dosing?
How much?
How often?

Do you know your PH, dKH, or dGH?

Tell us about your lighting

Please share!

lake_tuna

T5HO 2 WPG over 20gL
CO2 injected
Dirt tank
No ferts added
Ph around 8 (don't know other params)

I just got Flourish and been dosing this for a few days to see if this issue goes away. I've noticed my rotalas aren't growing that much, also.

hoppycalif

A 20 gallon long tank is about 12 inches high, and 30 inches long. You probably have a 2 bulb Coralife T5NO light, which would be giving you about 80 PAR at the substrate. That is high light. So, you need to be dosing both macro nutrients, NPK, and micro nutrients. Flourish works as a micro nutrient fertilizer, but does not provide enough macro nutrients to be effective. Your dirt substrate does provide NPK, but not in adequate amounts to meet the plant needs with that much light. You also need to provide CO2 to get good plant growth without having major algae problems.

lake_tuna

Yeah, I have 2 24" (30" fixture though) T5HO bulbs. So, this falls under highlight for this tank/height, you think? I would've thought it would be medium at most.

I am dosing CO2 with a paintball system, with the CO2 indicator showing the optimal level. I have very little algae and have been so for a while. I am seeing decent growth on glosso and pearlweed, but the rotalas aren't growing all that much.

I did hear about how Flourish is really insufficient, but wanted to give this a try before I get the individual nutrient products.. Which seachem products do you recommend?

DutchMuch

I recommend NilocG products. Just sayin'

hoppycalif

I agree, but if you like paying for plain water with a tiny bit of chemicals in it, you can get Seachem's "Flourish Nitrogen", "Flourish Phosphorus", and "Flourish Potassium". That is an expensive way to fertilize!

I misread my data on PAR for various lights: The 2 bulb Coralife T5NO light should give you about 40 PAR, and the T5HO version should give you about 60 PAR. The first is low medium light, and the second is between high medium and high light. In both cases you do need to provide some nutrients, and some CO2 - fairly high CO2 for 60 PAR, around 30+ ppm. It is hard to measure ppm of CO2 in an aquarium. I use a drop checker, but I also use distilled water in it with baking soda enough to get at KH that makes the drop checker solution turn yellow when I have 20-30 ppm. I use DIY CO2, so I don't need to worry about going too high in CO2. When you do have to be concerned about too much CO2 you need a KH that makes the color turn yellow if you have too much.