[conceptdos]

Hi all, I'm new to this planted tank hobby and happy to be here. I have a 29 gallon and a Nicrew Classic LED Plus with the below listed plants stocked.

My questions are:

1. This Nicrew light is listed PAR 75 @ 12inches. Is this enough light for the plants listed below? From my research, it seems I may need something strong, but I'm not sure.

2. Does PAR 75 refer to when it's at 100% strength?
a. If so does the dimming % directly correlate with PAR (i.e. PAR 37.5 @ 50%, etc)?

3. I just set the tank up and am planning on having one hour ramp up to 40% light strength, 5 hours @ 40%, then 1 hour ramp down to dark. How long should I run this schedule for before reassessing plant needs, algae growth, etc, and adjusting accordingly?


Plants:
Moneywort
Limnophila hippuridoides
Ludwigia Ruby sp. dark red
Rotala indica
Hornwort (submersed- tried to float it but it kept sinking which I think means it's adjusting)
Dwarf Hygrophila
Crypt Lutea
Anubias (forget which kind)


Thank you for the insights!

 

[jeffkrol]

Generally speaking dimming correlates with par
Lights are tested by manuf. at 100%
Unless they show a par map it is the sweet spot dead center so really max par for that height in a smallish area.

 

[Deanna]

If I recall correctly, that light is probably going to deliver, at most, about 50 PAR at the substrate, in a 29-gal, which is considered medium light. I wouldn’t expect algae problems as a result of too much light, but the Limnophila, Ludwigia Ruby and Rotala Indica may struggle a bit in terms of getting the full coloring that you see advertised. The Limnophila may be the most problematic.

I think that I would start by trying full light for four hours and ramping at your pleasure. Then reassess in two weeks. IME, dimmers deliver no more than about 90-95% of rated full power when set to 100%. I don’t know if this is the case with your setup.

Since you don’t seem to be adding CO2, you would probably benefit by adding Seachem’s Excel to supplement carbon. Also, make sure that your fertilizer dosing keeps up with the plant needs.

 

[conceptdos]

Thanks @jeffkrol .

Appreciate it, @Deanna . Would it make life easier if I just got a different light? I see that Nicrew’s Sky LED Plus has a considerable higher PAR rating, and am open to osuggestions.

That’s correct that I’m not injecting CO2 at this time. I have some Excel that I’ll use.

Lastly, what are biggest signs to look for that would indicate fertilizer dosing (i.e. what’s suggested on the bottle) isn’t keeping up with plant needs?

Thanks again.

 

[Deanna]

Would it make life easier if I just got a different light? I see that Nicrew’s Sky LED Plus has a considerable higher PAR rating, and am open to osuggestions.

No. Without pressurized CO2, 50 PAR, at the substrate, is about as far as you should go. Any more light and you will risk burning out your plants and creating algae.

Lastly, what are biggest signs to look for that would indicate fertilizer dosing (i.e. what’s suggested on the bottle) isn’t keeping up with plant needs?

Best to follow manufacturer guidelines. You m ight also take a look at this nutrient dosing calculator: RotalaButterfly

Consider starting with the "EI Low Light/Weekly" setting.

 

[conceptdos]

Thanks much @Deanna

Hi @Deanna , Once I've gone for 2 weeks or so with the 100% light for 4hrs/day, what are the signs that I'll want to increase the amount of time the light is on? Just slow growth?

 

[Deanna]

I would say that, if you have no negatives, increase by a half-hour each week or so until you see either a negative change or no improvement. The sweet spot for the plant health / algae minimization trade-off is probalbly in the area of six hours a day, but we also have to consider your viewing pleasure. We sometimes push a little harder (I used to do it with low-tech) in order to get more viewing time and accepted the negatives (Excel helped).

 

[conceptdos]

ok thanks @Deanna . Last question--- would you expect it to have any effect if I left the light on for several hours per day at 5% or less? The tank is in my basement and, unless I'm in the room working, it'll likely be dark. It would seem odd to have the tank (with fish) in a dark room for so many hours per day.

My plan would be to put the light @ 100% for 4 hours and increase as fit. Ramp up / ramp down on either end.
Set to 5% or less for 6-8hrs/day.
Lights off over night.

I could also just leave a room light on if the LED will still affect things at < 5%.

Thanks.

 

[Deanna]

No, I would not expect any problems. Photosynthesis will still occur, but at very low levels.

The issue with light is when there is too much of it. Plants don't know that they should stop working when they run out of food. Carbon is their favorite meal and, mainly, they get that from CO2 (Excel can supply some of the carbon, but not much). As light increases, so does their 'metabolism'. If there is not enough carbon, they starve, in a sense (we can give them all the other 'food' - fertilizers - fairly easily). When they begin to starve, they start dying and start giving off ammonia (food for algae). So, we end-up with faltering plants and thriving algae. Add sufficient carbon, via pressurized CO2, and we can increase both the intensity and duration of light. It becomes a balancing act between too much light and too little carbon, and each tank will be different.

 

[conceptdos]

Makes a lot of sense. Thank you again for your thorough explanations!

 

[jeffkrol]

50O ft candles is roughly 70 "PAR".
Most aquatics are considered low light plants.
Below the blue line is the point where nutrient use exceeds nutrient creation so to speak.
(CO2 out exceeds CO2 in).

 

[conceptdos]

Though the colors look fine, the Ludwigia is already losing some leafs and parts of the stem are breaking off. Could this potentially be to not enough light? I have it directly under the light but I read this may be due to not enough light.

The rotala indica is not losing leafs but does look kind of pale green / white-ish.

For ferts im using API root tabs and Aquarium Co-Op Easy Green.

 

[Deanna]

These are the plants that, as previously indicated, could be a problem without enough light. First, make sure that you are adding enough nitrogen/nitrate and iron.

 

[conceptdos]

thanks @Deanna. ok, will do.