Corals decline every day at the same time, please help me figure out why!

[Jelpin16]

Hello everyone I am at a bit of a loss on this one.

My tank is a 75 gallon aquarium mixed reef with sps, lps, and softies. For a long time I was battling against tin in my tank but was recently able to remove it and the corals looked amazing.

About a week ago I noticed reduced PE and tested my nitrates to find them at 0.0. I turned off my skimmer for a day to see if that helped and when I got home that night everything looked terrible. I also mixed new 2 part around this time. All sps polyps were retracted, zoas closed and lps mad. I did a 20 gallon water change and things were better the next day. I thought it was lack of oxygen. I also began feeding more and dosing small amount of neo nitro to get nitrates up slowly

I then started to notice this would occur at relatively the same time 7-7:30pm every day. Sometimes I would see white filaments hanging from the one colony thicker than zoanthelae.

I had recently mixed up a new batch of brs soda ash 2 part so I drained the dos lines emptied the resovoir and started a new batch in case there was a contaminent but still the problem remains.

Parameters are as follows
Po4-.05
Nitrate-2.5
Alk-8.6
Calcium-450
Magnesium-1400
Ph at time of PE loss-8.2

These values are confimed via trident, hanna checkers, and salifert tests.

There is no dosing of either 2 part from 5 until 10pm.
Lighting is hydra 32 and t5 from 11-11 with the t5s turning off at 5. Everything looks better by 11 the next day and continues to look good until the decline. Pictured is a acro colony before and after the switch happens. Recent icp tests shows everything where it needs to be aside from low iodine. Is it possible the whole brs soda ash batch is bad and there is just a 2 hour delay before everything is affected? It is also dosed overnight and 4-8 am but does not seem to have the same effects.



Thank you for reading this long post, any help would be greatly appreciated!

 

[blaxsun]

Could it be due to the T5s turning off at 5pm?

 

[Jelpin16]

Could it be due to the T5s turning off at 5pm?

I had considered this, I have slowly been increasing led intensity to reach 250-300 in the upper portions of the tank when t5s are on. When the t5s turn off it is closer to 150, would this trigger it? I thought PE would be high if they were thinking it was night?

Thanks for the reply

 

[damsels are not mean]

Sounds like they are going to sleep

 

[Jelpin16]

Sounds like they are going to sleep

Im going to extend t5 time by an hour and hopefully will se an hour delay in polyp recession.

 

[bruno3047]

Im going to extend t5 time by an hour and hopefully will se an hour delay in polyp recession.

I think you’re missing the point. The corals are being controlled by their internal clock. Not by what time you decide to turn your lights on and off. Forcing them to stay awake when they don’t want to is just stressing them out.

 

[Harold999]

Miss salinity in your parameters, and doublecheck with something else you normally check it with.

 

[Jelpin16]

The lights turning off still seems unusual as with the leds being turned up the switch with no t5s would be the same drop as it was before just the overall par being higher throught the day.

But maybe this difference in high is causing the trigger.

Thank you for your thoughts

 

[Jelpin16]

I think you’re missing the point. The corals are being controlled by their internal clock. Not by what time you decide to turn your lights on and off. Forcing them to stay awake when they don’t want to is just stressing them out.

This change has been observed in the last week and has not occured over the last year and a half the tank has been set up. The lighting schedule has not changed in this time aside from higher par, why would they be showing this change now?

 

[Jelpin16]

Miss salinity in your parameters, and doublecheck with something else you normally check it with.

Forgot that one, salinity is 1.025 but I will recalibrate again to double check

 

[bruno3047]

.

 

[bruno3047]

You have to consider that the higher par is going to result in increased photosynthetic activity and an increase in oxygen production inside the coral. This could be stressful.

 

[bruno3047]

This change has been observed in the last week and has not occured over the last year and a half the tank has been set up. The lighting schedule has not changed in this time aside from higher par, why would they be showing this change now?

That’s what you have to figure out. But I think the point you brought up about the light intensity might have something to do with it. I had a similar situation in my tank. I used to like to watch the night critters under the blue moon lights so I started keeping them on until midnight. My corals didn’t like this at all and they let me know about it by not opening fully during the day. So I switched back to moon lights off at 10:30 and everything is fine again.

 

[reefiniteasy]

My lps begin closing up 3 hours before lights out. My frogspawn and bubble coral shrink and go to sleep. Every day at 6pm on the dot.

 

[Dkmoo]

It takes energy for corals to expand their polyps. When corals "got enough of what they need" they will retract and rest. Thats why you can't look at PE alone and decide if you have too much vs too little light bc both can happen depending on other factor. High PE can result from both high par and low par - it all depends on if the coral thinks its more energy efficient to open vs close

In your case what I suspect happens is that back when you had lower overall par output, your corals needed to stay open longer to get all it needs. Now that ur peak par is higher for longer period, the corals got all it needs so they dont need to open as long when the tank goes dark.

The rest of your params look in line so I wouldn't worry about it until I see real evidence of something wrong, like receding tissues. Trying to fiddle with lighting sch or make other "corrections" just introduces more instability and do more harm than good.