View Full Version : RE: LED Lights - Plants doing well for years and past few months are pale and stunted

06-07-2013, 11:49 PM
Have 90 gallon tank that has been using LED lights (TMC Aquaray Aquabeam Natural Daylight - Models 500 and 600 that are supposed to be in the 6500K natural daylight spectrum) for the past few years. I had the lights such that I wasn't having to do CO2 injection by cycling the lights on/off which helped minimize algae growth and the plants were all doing fine. Usually would have to prune the plants every other week as they would be hitting the top of the tank. Now it has been a few months since the last pruning and not looking so great. Algae is not an issue except for some algae growing on the glass, so I would presume I have enough ferts to allow the plants to grow.

The plants are stunted, very pale green rather than dark green. Although with algae growth I still thought ferts might be the problem, so I picked up a few boxes of flourish tabs and put in the gravel. It's been about 3 weeks with the tabs in place and plants still are not doing so great. Only plants that are seeming to be okay are some moss for my cherry red shrimp. The moss is doing very well in 4 or 5 places in the tank.

I did have 3 large adult discus prior to when the problems started and two passed away and now only have 1 discus left (both were old, the one 1 that is left was a juvenline from auction 2 years ago). Could the fish load not be sufficient to give the plants what they need? I have checked most water parameters and most look normal, or is there one in particular I need to investigate more?

Is there an easy way to check the PAR / Spectrum of the LEDs?


06-08-2013, 05:53 PM
Are you feeding a lot less? That would lead to lower nitrate, and possibly phosphate. You wouldn't necessarily see a change in the levels if the plants were eating all that was available.
The next possibility is that you've cut back on water changes as thus the plant's supply of trace elements (potassium, iron, etc) isn't getting replenished like it used to. This could show up in levels. The third possibility would be that the tank has finally run out of something it had at the beginning, maybe in the substrate. So root tabs make sense here. The fourth thing is that the lights are losing intensity with time, I think LEDs do this less than fluorescents, being more likely to just die, So testing is a good idea though I don't know where you can borrow a meter.

One plant talk we had said to potassium is the first thing to look at. Or try a really huge water change (add new water slowly) to "reset" levels, test and then dose what is still missing.