unhealthy plants with pics...please help

[jaguarr]

Could someone please tell me why my plants have brown spots, dots on their leaves?

In the first photo, you can see that the newly grown leaves are light green (healthy), but the old ones are covered with brown spots.

In the second picture, you can see the plants (dont know its name) are pink on the top (healthy), but the leaves below have either fallen off or about to.

Is this because of a lack of iron, potassium, CO2?

A little bit about my tank...
- 29 gallon
- one 65w Power Compact in the back, one 40w regular flourescent in the front (the light that comes with 55gallon tank), 10hr/day
- DIY CO2, 2 liter, air stone at the end to decrease the bubble size, then are taken in by the power head and distributed throughout the tank
- water condition: 7.4pH, 77 degree F.
- 25% water change every week or twice a week if I have time
- fertilizers I use are shown below. I added 20mL of the "leaf zone" once a week and placed the tabs once every two weeks at where the rooted plants are (half a tablet to one, depending on the plant size)

 

[mattrox]

It looks like brown algae. I am not an expert on algae, but do you knoe your nitrate concentration? What about Phosphate?

How long have the plants been in the tank. Old growth will get algae on them first as they have been exposed to the water for longer than new leaves.

 

[jaguarr]

nitrate 0
phosphate 2 ppm or above
plants have been in tank for more than a month.
I just added some phosphate remover (synthetic ferric oxide hydroxide)

anything else I should monitor, change?

 

[mattrox]

You should have some nitrate.

 

[frog girl]

I think a lot of folks dose with KNO3 when they have a nitrate deficiency. You may need to blend you own fertilizer to get your algae under control. Or you can just live with a bit of hair algae (I haven't gotten to custom blending yet with all the outside spring work so I too have a bit of hair algae).

At http://www.thekrib.com/Plants/Fertilizer/pmdd-tim.html

there is a plethora of information about balancing your nutrients to get an algae free tank. It has a recipe for making your own fertilizer too. Apparently phosphates with no nitrates = algae. If you don't have time for all this now you might try acquiring a hair algae eater until you can allocate the time to brew some stuff up. I think its rosey barbs that I have read are good at it (double check though) & of course the SAE etc.

HTH

 

[Jchillin]

Those brown spots are indeed diatoms. This is caused by excessive nutrients in the tank. These nutrients NO3, food waste and light (the same ones that your plants will utilize) allow the diatoms to flourish as well.

Since you have @ 3.6wpg and are dosing CO2, you are going to have to try a balancing act to find the correct balance.

In the meantime, frog girl has made an excellent recommendation. I would also trim the light hours for awhile.

 

[jaguarr]

thank you guys very much for the comments

 

[travis simonson]

Damage to older leaves can also occur due to K (potassium) deficiency. I had the same problem with my Cryptocorynes until I started dosing 10-20 ppm of K per week. Symptoms of K deficiency include pinhole damage and glassiness of older leaves, especially on slow growing plants. Have you noticed streaming (i.e. a column of bubbles shooting to the surface) from your older leaves? If so, it is likely you've got pinhole damage due to K deficiency. Check out www.gregwatson.com for potassium sulfate at very affordable prices. Even if it doesn't solve your problems, it can't hurt