Cant seem to keep macro algae alive

[disaster999]

I cant seem to keep any macro algae alive. I have a separate custom made 30L, 8gal, tank with a 50W LED grow light. Water is fed from the output of my chiller and the flow isnt too high, around 100L/h maybe. Ive tried to keep chaeto, grape algae, red macro algae, feather caulerpa and they dont seem to grow much but rather slowly die over time. Ive kept some bigger grape algae before and they do grow but after a few trimmings they just died. I dont think my tank has very little nutrients, my current parameters are:

Calc: 410ppm
Alk: 7.7
Mg: 1290ppm
No3: 5ppm
Po4: 0.06

Is my light too strong? Do I need to turn it down?

 

[MossyFroggyLove]

50w for an 8gal seems too high. For me at least. I have a total of 50w light in my 20gal. But i do know that chaeto needs highlight and i keep mine directly under my 30w light. But feather caulerpa should be pretty easy. But mine grows at medium to low light. So i dont know. Might be too much light.

 

[courtneykeeps]

I can only go on the information that you've given. Based on that I'm willing to bet that you're running out of nutrients. Those nitrate and phosphate levels are right on the edge and could be dipping too low and causing the macroalgae to go sexual.

 

[MossyFroggyLove]

I am not sure if nitrates might be the problem. I mean my macroalgae was doing fine even when my tank had untraceable nitrates for a whole 3 weeks. Though my po4 stayed high. So, i do think low nutrients is the issue too because i usually see really good macroalgae growth when nutrients are a little high.

 

[disaster999]

I was talking to my LFS and they said based on my tanks parameters it should is able to keep macros alive. My friend who has similar levels as my tank has no problem growing his algae.

Maybe I do have low nutrients level, I try to feed daily but sometimes I get home too late to be able to feed.

 

[Subsea]

I was talking to my LFS and they said based on my tanks parameters it should is able to keep macros alive. My friend who has similar levels as my tank has no problem growing his algae.

Maybe I do have low nutrients level, I try to feed daily but sometimes I get home too late to be able to feed.

In my macro tanks, I dose ammonia to keep up with nitrogen demand.

I think your lights are too intense and you are nitrogen limited with respect to fast growing macro algae.
Also, what temperature does your 6G AIO maintain if it is on the discharge of your chiller?

 

[sjfishguy]

With the chiller water flowing in, Ever check the temp of the water in there?

 

[CHSUB]

Please don’t think 5 ppm no3 is the problem. My tank grows macros easily and not on purpose, came in on live rock and harvested occasionally. Also have 7 mangroves, hobby testing shows 0 no3. This belief that readable no3 is required has become silly with the “new” hobbyist….
Wouldn’t think to much light is possible but mine grow with high flow. So might be opposite of your thinking on flow, try adding a small powerhead.

Just to confirm this is 0 no3…

 

[Mr. Mojo Rising]

Is there any flow in the tank?
I've been growing red macro algae in a 10 gallon for the past 2 years. I use a 100 watt plant grow light, I feed the one damsel twice a day and I do water changes once a month. I have 2 small powerheads in the 10 gallon. Do you have any flow in your tank?
I have no idea what I'm doing actually but the macro algae grows like crazy.

Maybe if you post a tank picture folks might have more suggestions for you.