[trenac]

First you need to test your water parameters...PH, KH, N03, P04

Next you need to up your lighting period to 10 hours a day.

How many gallons is your tank?... It looks big in the pic and with 144 watts of light you may need more wattage.

You say your plants are not growing well, it is more than likely a lack of N03. Also you need to dose micros & macros at least once a week or more.

You can try putting a root tab under the swords, but with the look of things you have a bad deficiancy and maybe lack of light.

The most important thing is test your water parameters and post them so we can help you better.

 

[trenac]

Is your bulbs florescent plant bulbs (5500k-10000k)?

If your plants are growing slow then you are most than likely lacking nitrates, make sure to test your N03 reading.

 

[trenac]

Did you ever test your water parameters?... If the signs are showing on all your plants and not just on the swords then it is most than likely not the Pleco but a deficiency. I keep Plecos with swords with no damage done. Low nitrates will cause your plants to grow slow.

Yeh, there are other plants with simular sort of problem. I noticed all my plants seem to grow slower then usual. The tank is 48 X 18 X 18 inch about 55 gallons. The fluros are pretty new, so no problems there... i think i probaly have a lack of nuterients in the water... shall test the water and return with results.