Cheato Shrinking under red light

[sen5241b]

Why has my  chaetomorpha shrunk from a basketball size clump to almost nothing? I have a regular plant grow bulb and a red light grow bulb ("ABI 25W Deep Red 660nm LED Light Bulb Bloom Booster for Flowering, Fruiting, and Grow Spectrum Enhancement",   https://www.amazon.com/gp/product/B071Z12H67/ref=ppx_yo_dt_b_asin_title_o05__o00_s00?ie=UTF8&th=1)   I guess the obvious answer is low phosphates. Is the red light thing nonsense? Maybe phosphates are low because of the cheato but then shouldn't it have grown bigger? More light? Add another fish?

Edited February 19, 2019 by sen5241b
typo

[mogurnda]

If you want to make your pot plants produce buds, then use the red "bloom" light.  Apologies if this violates forum policy, but that is truly what the bloom setting is for.  Macroalgae do not produce flowers, and will want a balance of red and blue, and it does not hurt to have some of the middle of the spectrum as well.  I do not expect that the red is hurting your algae, but it is not likely to be helping.

 

I have had Chaetomorpha growing well in near-zero phosphate, and have more trouble with it if the PO4 gets too high.  

 

Mine waxes and wanes for unknown reasons, so it may be something like that, or it could have become too dense and had poor circulation on the interior of the clump.

[YHSublime]

If you want to make your pot plants produce buds, then use the red "bloom" light.  Apologies if this violates forum policy, but that is truly what the bloom setting is for.  Macroalgae do not produce flowers, and will want a balance of red and blue, and it does not hurt to have some of the middle of the spectrum as well.  I do not expect that the red is hurting your algae, but it is not likely to be helping.
 
I have had Chaetomorpha growing well in near-zero phosphate, and have more trouble with it if the PO4 gets too high.  
 
Mine waxes and wanes for unknown reasons, so it may be something like that, or it could have become too dense and had poor circulation on the interior of the clump.

I’ve never been able to grow macro until I added a red light, with I think only 2 blue LEDs out of 12? Now it’s seemingly doing well. Dragons breath is doing well under my regular reef tank light though, as well as under my red fuge light. Just my observations!


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[sen5241b]

I've had the red light for about year and it did not make any dramatic difference.

[madweazl]

Any idea what your iron levels are?

[DFR]

What are your nutrient levels, and what other forms of filtration do you have?  Also do you have any signs of other algae that is growing under your light?