Understanding algae, nutrients, and coral growth

[slogan315]

Been doing lots of research, and I need help understanding lots of these “facts” I’ve read.

understanding my perspective:
My tank has:
- higher alk ~10.5
- low nutrients: n/p, <1/<0.1
- GHA is growing

I feel like my LPS aren’t doing great, and thought it might be the combination of high alk and low nutrients. So my research focus has been on increasing nutrients.

Questions:
That brings up the question, how to you increase nutrients without fueling more GHA? The answer seems to be CUC. Okay so does a reduced amount of GHA mean it uses the nutrients slower, giving my corals time to use it for tissue growth? That then gets my head spinning on the purpose of a refugium if my nutrients are too low. (Not going for an ULNS here). I get that a refugium uses a macro algae to outcompete the nuisance algae for nutrients. If your time your refugium photo period to leave some nutrients in the water, won’t nuisance algae use it all?

struggling to understand how nutrients say in the water without causing an algae bloom…

 

[thatmanMIKEson]

Good questions, do you have a little more background of the system, its not exactly a one answer fits all systems. Every healthy system should have algae IMO

The blanket, one size fits all answer is to do manual removal and increase cuc, allowing coraline algae to cover all surfaces, which will out compete the nuisance algae.

 

[slogan315]

Good questions, do you have a little more background of the system, its not exactly a one answer fits all systems. Every healthy system should have algae IMO

The blanket, one size fits all answer is to do manual removal and increase cuc, allowing coraline algae to cover all surfaces, which will out compete the nuisance algae.

Yes the system is a 60g cube with basic sump (socks and skimmer). The rock has been cycled for 2-3 years. I bought it as a used system about a month ago. Sand was tossed and now BB, but everything else was used. I rescaped a few weeks ago which exposed some of the previously shaded rock. Symptoms have been GHA and some burning/bleaching on growing tips of LPS. I light acclimated really conservatively so I don’t thing it’s that.

corals that came with the system are doing great. Newer corals I got from wwc are doing fine, but not great.

 

[slogan315]

But my questions are more theoretical about learning nutrients and the role they play, more than trying to fix my problem.

 

[thatmanMIKEson]

But my questions are more theoretical about learning nutrients and the role they play, more than trying to fix my problem.

Lots of info out there for that then, enjoy the researching!

 

[ReefGeezer]

It is really too bad that algae issues aren't just nitrate and phosphate related. That would make it soooo easy to control. In reality, algae (and all the other algae like pests) cease to become a problem when two things happen: 1) The substrate develops a coating of biofilms i.e. coralline algae, bacterial colonies, and corals that compete with the algae for space; and 2) Organisms in the tank develop that compete for the algae for nutrients i.e. bacteria, sponges, corals, clams, macroalgae, and etc.. @thatmanMIKEson had a good suggestion to do manual removal until these things catch up in your tank.

Your burned tips might could be alk related. The higher alk can encourage skeletal growth that can't be matched by the coral's flesh due to low available nutrients. That's usually more of an SPS problem though. If you can just let if fall to <8.0 you wouldn't need to increase nutrients much... Switching to a lower alk salt might be required. If your tests are accurate a little extra feeding would probably raise nutrients enough.

 

[slogan315]

It is really too bad that algae issues aren't just nitrate and phosphate related. That would make it soooo easy to control. In reality, algae (and all the other algae like pests) cease to become a problem when two things happen: 1) The substrate develops a coating of biofilms i.e. coralline algae, bacterial colonies, and corals that compete with the algae for space; and 2) Organisms in the tank develop that compete for the algae for nutrients i.e. bacteria, sponges, corals, clams, macroalgae, and etc.. @thatmanMIKEson had a good suggestion to do manual removal until these things catch up in your tank.

Your burned tips might could be alk related. The higher alk can encourage skeletal growth that can't be matched by the coral's flesh due to low available nutrients. That's usually more of an SPS problem though. If you can just let if fall to <8.0 you wouldn't need to increase nutrients much... Switching to a lower alk salt might be required. If your tests are accurate a little extra feeding would probably raise nutrients enough.

Thanks for the response. This makes a lot of sense. So in a more mature tank with a mature coating of coralline and bacteria colonies, it deters algae. And refugiums / water changes can help export excess no3/po4. I actually just noticed where coralline has spread from a frag plug, and it has removed the nuisance algae from that spot. Hoping this continues!

despite the nuisance algae growth, I’ve been trying to feed more to promote nutrient levels rising. Hoping this starts to improve as well. I like the alk range I’m in of 10-10.5 long term and would prefer to just raise nutrients. We’ll see how it goes! May be a justification for adding another fish…

 

[ReefGeezer]

Thanks for the response. This makes a lot of sense. So in a more mature tank with a mature coating of coralline and bacteria colonies, it deters algae. And refugiums / water changes can help export excess no3/po4. I actually just noticed where coralline has spread from a frag plug, and it has removed the nuisance algae from that spot. Hoping this continues!

despite the nuisance algae growth, I’ve been trying to feed more to promote nutrient levels rising. Hoping this starts to improve as well. I like the alk range I’m in of 10-10.5 long term and would prefer to just raise nutrients. We’ll see how it goes! May be a justification for adding another fish…

Any excuse to add a fish is good!

 

[I never finish anythi]

Phosphate @ 0.1 ain't that low .

Not saying that's the problem, but when my tank had phosphate that high I had algae.

I got a sea hare , lowered my po4 to 0.03 and the algae has now gone.

 

[I never finish anythi]

Phosphate @ 0.1 ain't that low .

Not saying that's the problem, but when my tank had phosphate that high I had algae.

I got a sea hare , lowered my po4 to 0.03 and the algae has now gone.

Nitrate between 5 / 10

 

[slogan315]

Phosphate @ 0.1 ain't that low .

Not saying that's the problem, but when my tank had phosphate that high I had algae.

I got a sea hare , lowered my po4 to 0.03 and the algae has now gone.

Yea I say <1 po4, but it has been swinging from 0.1-0.02. Yesterday it was at 0.03

 

[I never finish anythi]

Yea I say <1 po4, but it has been swinging from 0.1-0.02. Yesterday it was at 0.03

I might have missed it , but what do you test with ??

 

[slogan315]

I might have missed it , but what do you test with ??

Hanna

 

[Randy Holmes-Farley Verified Community Expert]

Algae problems are often not best solved (or prevented) by chemistry, and in reality, if phosphate is 0.1 or 1 ppm likely makes little to no difference to algae because they can get all they want at 0.1 ppm. In others words, its not a limiting nutrient to growth at that level.

 

[slogan315]

Algae problems are often not best solved (or prevented) by chemistry, and in reality, if phosphate is 0.1 or 1 ppm likely makes little to no difference to algae because they can get all they want at 0.1 ppm. In others words, it’s not a limiting nutrient to growth at that level.

Hey Randy, if I were to start dosing nitrates until I get more livestock, is it important to slowly raise the levels for the safety of the livestock? Or is it fine to try and get to 5-10ppm as quick as your system will let you?

 

[Randy Holmes-Farley Verified Community Expert]

Hey Randy, if I were to start dosing nitrates until I get more livestock, is it important to slowly raise the levels for the safety of the livestock? Or is it fine to try and get to 5-10ppm as quick as your system will let you?

I do not think an instant boost is any concern.